Instructables

Light Electric Vehicle: One-Passenger @ 15mph, 210# Curb Weight

I designed and built this fun and successful light electric vehicle several years ago. I'm just now posting it on "Instructables" and will add more steps, detailing the construction, in the next few weeks.

Use the link to my webspace, for the details, for the time being:

www.home.earthlink.net/~hcf-305userforum

I decided to build an electric vehicle from off-the-shelf components, using existing technology. The goal was to define auto transportation, down to the basic motor vehicle errand: One passenger plus a sizeable payload, to and from destinations of up to 5-10 miles away, rapidly, all at an affordable price.

And electric mobility scooters, unlike most electric automobiles, seemed to already be on the right track -they just needed to run faster. And, after checking the mobility scooters on the market, the HCF-305 seemed uniquely suited for the project. It actually ran so fast that it got the manufacturer in trouble and the medical mobility vendors quickly unloaded their HCF-305 inventories. And I knew that this vehicle would be perfect for the task.

I began to modify the HCF-305, by first installing an ultralight aircraft seat and harness for comfort, stability, and protection, and then building up the body around it.

This homemade vehicle is classified as a "Light Electric Vehicle": A new breed of efficient, lean-and-mean machines that weigh little more than the passenger(s). The Light Electric Vehicle is powered transportation distilled to its essence.

The issue with most electric vehicles these days is that they often weigh in at 2,500 pounds or more. And such a vehicle has the daunting obstacle of simply transporting itself, which is, at best, a losing battle.

Another uncomfortable truth is that full size electric vehicles put a strain on the local electric power grid: Most communities do not have the electric power infrastructure, specifically, neighborhood power lines and transformers, to properly charge more than one or two full size electric vehicles per neighborhood.

Now, I have 3,000 miles (360 charge cycles) logged on this vehicle. Everywhere I drive this odd duck people approach me, wanting to buy one. I politely tell them that I would starve if I made these things for a living.

This project is not unlike my radio control model aircraft: It's a true labor of love -that requires a considerable amount of research and tinkering to keep everything running smoothly. But the casual bystander only sees a cute, reliable vehicle that quickly and effortlessly runs errands all over town. And it would be a quite a stretch to assume that this vehicle is anywhere near ready for the mass market.

Like many members in my local Electric Automobile Association, I see my electric vehicle as a toy and a joy, and certainly not yet a viable substitute for an internal combustion engine vehicle.

But we try.
 
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Step 1: Unorthodox Treatment for High Rate Sealed Lead Acid Batteries:

*** Here are the details as to how I built a successful lead-acid battery pack for my light electric vehicle. But due to the outstanding success of my Lithium-Iron Phosphate battery pack, I am no longer an advocate of lead-acid batteries for electric vehicles. See the details in the Lithium-Iron Phosphate battery section of this Instructable. 

After quickly burning out two OEM 24 Volt 40 Amp battery packs, after only 50 miles each, I've installed and had excellent results with a different replacement set of batteries for my light electric vehicle:

Four - 12Volt, 21Amp PowerSonic PSH-12180NB-FR batteries, producing a 24 Volt, 42 Amp battery pack.

But, upon receiving the delivery of the batteries, I promptly pried off the sealed plastic panel, which covers the six soft rubber valve caps to the cells, and added almost 1-1/2 fluid ounces (44.4 milliliters) of standard battery electrolyte solution (an over-the-counter product of 35% sulfuric acid and 65% water) to each cell, for a total of 9 fluid ounces (266 milliliters) per battery. The electrolyte level just needs to cover the lead plates, and no more. Standard lead acid batteries require topping off with an electrolyte level of almost 1/2" over the lead plates, but your sla agm batteries are far better off with less.

To inject the electrolyte into the cells, I prefer to use a small, el-cheapo battery electrolyte bulb tester, with the colored plastic balls removed. The pointed tip of the bulb tester is inserted into the small cell opening, and the electrolyte is quickly squirted into the cell so that the solution doesn't have a chance to flood onto the outside-top of the battery. The battery cell is then inspected with a small led flashlight, to see if the lead plates are just covered by the electrolyte, but no more. A darkened room, or shed, is best for this. A thin, plastic drinking straw (chemically inert) comes in handy, in case a bubble in the cell hole is blocking your view, to poke it and pop the bubble.

Breaking open and "topping off" a perfectly good set of new batteries and voiding the warranty may sound shocking and radical to most people. But, after thoroughly reading up on the subject, I came to the conclusion that my judgement is correct -and the advice of the battery specialists is either wrong or non-existent. You see, sealed acid batteries are, by their very nature, "starved electrolyte", due to the simple fact that the fiberglass mats between the lead plates are only 95% saturated, in order to make them spill proof. As such, water depletion of the "sealed" system is a constant concern. Performance can only take a back seat when a battery is designed this way.

Another benefit of flooding a sealed lead acid battery is to provide an inherent ability to dissipate heat. That is, typical flooded deep cycle batteries may normally become warm to the touch, either from heavy use, or from quick charging, but if a sealed lead acid battery ever becomes hot (or even warm) to the touch, the internal lead/glass mat cells, more than likely, have dried up and burned out, due to the complete inability of the empty spaces in the cells to dissipate intense heat away from the lead plates.  Another symptom of a sealed lead acid battery that is burned out (aka: thermal runaway) is that it also vents off a sick vinegar smell.

And if the new high-rate sealed lead acid batteries were truly reliable, then why haven't the golf cart manufacturers installed them, making their vehicles lighter and more responsive? I feel that those relatively expensive, compact, and high-performance sealed lead acid batteries must be flooded (electrolyte added), to enjoy their maximum potential.

The electrolyte added, the six soft rubber cell caps were replaced onto the battery cells, and any spilled electrolyte from the top of the battery cleaned up with a paper towel.  I then punctured each of the six soft rubber cell caps, in the middle, with a standard push pin, to eliminate the internal vacuum that happens as the batteries cool back down to ambient temperature, causing the electrolyte in the glass mats to deplete to less than 95% saturation (*** Warning:  At one time, with an earlier battery pack, I placed the battery cell caps on a wooden board and punctured each one, in the middle, with a heated, red-hot straightened end of a paper clip, for even better ventilation of the cells, but the possibility of an electrical spark causing a battery explosion is greatly increased by the larger diameter vent holes and I no longer do it this way).  The now-flooded batteries, simply, do not have to be completely "sealed". The plastic cover was then fitted back into place, over the cell caps, and taped shut, lengthwise, leaving the ends uncovered, to allow for venting of the battery.

Working with battery electrolyte solution does require certain precautions (some say it's dangerous -but so is using a table saw, or driving a car):
- Only use standard battery electrolyte solution (an over-the-counter product of 35% sulfuric acid and 65% water). Never use pure sulfuric acid. It is extremely dangerous, as well as ineffective. And "topping off" with water will only weaken your sla/agm batteries, as they are not at all like typical flooded batteries.
- Make sure that there is someone nearby, within shouting distance, just in case electrolyte gets in the eyes, to help flush your eyes with water, or better yet, special emergency eye-flush solution. Or, if heavy electrolyte contact, a trip to the emergency room of a local hospital (but still do a first aid flush, as time is critical).
- Wear eye protection and wear old, worn out clothes. Small droplets of electrolyte have the insidious habit of producing large holes in your favorite yard work clothes, appearing a week or two after exposure. Cellulose products are surprisingly vulnerable to electrolyte solution (blue jeans, canvas shirt, wooden floors).
- Snug fitting latex (or nitrile) gloves should be worn. I only wear them sometimes. But any case, afterwards, hands should be scrubbed down with baking soda, and face, hands, and arms washed with soap and water.

The four - 12Volt, 21Amp PowerSonic PSH-12180NB-FR batteries were then wired, in pairs, in series, and then parallel wired, to produce a 24 Volt, 42 Amp battery pack.

But further reading on the subject indicates that the batteries may function better if first wired parallel, as 2 - 12 Volt groups, and then wired in series, to produce a 24 Volt battery pack. The reason for this is that a weak battery will not degrade the over-all battery pack as much, in this type of arrangement.

A 7/8" thick pad of Insulite, a closed-cell foam, resistant to battery electrolyte solution, was positioned under the battery pack to absorb road shock, as the shock absorbers on the vehicle were adjusted to maximum stiffness, to create a more efficient ride and maximize the range of the vehicle.

These high rate PowerSonic batteries were actually developed for emergency power backup systems, for computer networks, etc.. Although tried and proven in electric wheel chairs that cruise at 3-4mph, these batteries have not been extensively tested on higher performance powered vehicles. But they are formulated for high-drain usage -without damage. Also, being agm (absorbed glass mat) batteries, they have a strong tolerance of the shock and vibrations of an electric vehicle environment.

The caution here is that the HCF-305 is unique in that the OEM electronic controller allows the 600 watt motor to run the vehicle at 14 mph. This is a world of difference, from running, say, a 600 watt motor in a vehicle that will max out at 4 mph. In short, a set of sla batteries that have successfully run a wheel chair for years can quickly burn out when connected to a high performance electronic controller (as in the HCF-305) that runs a vehicle at 14 mph.

The original OEM battery pack (2 - 24V 20A batteries) for the HCF-305, at 24 Volts / 40 Ampere-hours capacity, is just not durable enough to power the vehicle at a 14mph cruising speed. It should have been designed with a 24 Volts / 70 Ampere-hours capacity sealed lead acid/absorbed glass mat battery pack + a 24 Volt / 70 Amp electronic controller, for this type of load. The OEM battery pack was designed to cruise at about 8mph, with , maybe, occasional 14mph speeds for racing against other mobility scooters out of the stoplight.

But this limitation can be worked around. Read on.

And another warning: Don't be tempted to build a custom 24 Volt battery pack that exceeds 40-42 amps. Doing so will quickly burn out the electronic controller. And substituting a higher capacity electronic controller will create a loss of many of the special functions that are unique to the HCF-305's performance and convenience. In short, a high performance, off-brand electronic controller will simply run the motor -and nothing else.

Measuring the same height, the same length, and half the width of the standard issue HCF-305 batteries, the pack of four PowerSonic replacement batteries fit snugly into the HCF-305 battery compartment. Be sure to fashion a means to tightly secure each and every battery into position. The HCF-305 has minimal sized shock absorbers and any bumping and movement of the batteries WILL cause the battery cables to come untightened and loose. And the amperage running in the battery cables is strong enough to melt steel.

Although the new batteries arrived pre-charged, it is imperative that the modified "topped off" set of batteries were given a full, overnight charge, using the standard HCF-305 charger. After charging, each battery will test at 13.5-14 Volts -yet another advantage of adding standard electrolyte to the sla batteries, adding extra "pep" to the performance, without overloading the HCF-305 electronic controller.

It makes no sense to enhance the battery pack performance on the HCF-305, if full power is restricted from reaching the electronic controller, and the motor. Specifically, the OEM 12AWG wiring harness needs to be replaced with a custom, more robust 10AWG automotive wiring harness.

The problem with the OEM 12AWG wiring is that it is really not adequate for fast discharge characteristics of running the HCF-305 at full cruising speed. The OEM 600 watt motor is also wired with the same 12AWG wiring, indicating that the motor manufacturer probably never intended that their motor be run that hard.

Also, the cross-section of the OEM 12AWG wire has no less than 65 fine copper wires, that are extremely vulnerable to trace amounts of battery electrolyte wicking deep into the wiring (acid wicked in and damaged 10-1/2" / 27cm of wire on my HCF-305!). Whereas standard 10AWG automotive wiring is much heavier, capable of handling 60% more current and, more importantly, the cross-section a typical 10AWG automotive wire has about 19 coarse copper wires that are far less likely to absorb battery electrolyte, and if that happens, is somewhat less susceptable to acid corrosion eating through the wiring, blocking the high flow of current.

Once fabricated, the lugged contacts, on the new red and black 10AWG battery pack cables, need to be carefully "tinned" with an electrical rosin core solder, to make the battery wiring more efficient. The battery pack cables have battery contacts that are originally crimped on, which can sometimes restrict large amounts of current to freely pass through, causing a "hot spot". Lead-based solder, with a much lower melting point (374 degrees Fahrenheit) than lead-free solder (430 degrees Fahrenheit) will freely melt into the copper braids of the wiring, with a 75 watt soldering gun, for a clean, heavy flow of DC current. Lead-free solder will probably require a butane pencil torch, to overcome the heat-sink nature of the heavy copper wire and quickly melt the solder well into the connector and wire.

But, if you choose to add electrolyte to your sla batteries (and you should), "tinning" is a required step. The reason is that there will always be trace amounts of electrolyte that somehow make it outside of the battery (from riding the vehicle over rough surfaces, etc.), and make contact with the battery terminals and battery connections. And once on the connections, an even miniscule amount of electrolyte can quickly wick into the braided copper wiring, to do its mischief and impede in the proper flow of DC current. "Tinning", while not preventing this corrosion, will effectively ensure a clean, heavy flow of DC current through the wiring at all times.

Initially, I simply cut off the OEM wiring connectors and replaced them with heavy duty 12-10 AWG ring terminals, for a #8-#10 stud, crimped onto the battery pack cables and "tinned" with liberal amount of solder. And then applied and worked in liberal amounts of special battery terminal grease, which also has special inhibitors to neutralize battery electrolyte.

The battery terminals and wiring connectors must be clean at all times. The powdery deposits that sometimes form on the terminals are result of battery acid corrosion. The battery pack can usually be charged through corroded contacts. But the high rate of battery discharge, required for driving the vehicle, will create "hot spots" where corrosion is present, greatly diminishing performance of the vehicle.

To remove corrosion from the battery terminals, I've found that a good spray of "Windex" window cleaner (substitute brands don't work as well), with its alkaline composition, quickly dissolves most corrosion and also wicks into the wiring harness to further dissolve any hidden corrosion. Saturating an old toothbrush with Windex works well in removing acid corrosion from the more stubborn areas.

"CRC" brand Battery Cleaner with Acid Indicator is also a quick and excellent aerosol product that has a thorough foaming action, with a yellow colored foam that turns pink, upon contact with acid. A second application, in the pink areas, leaves a thoroughly clean set of battery terminals and connectors. The instructions on the can recommend flushing with water, but I simply wipe clean with a paper towel, leaving some foam residue to neutralize any acid that might reappear.

If this doesn't completely remove all corrosion, take a small brass bristle brush (the size of a tooth brush) and carefully remove the remainder of the corrosion from the battery terminals and connectors. Any stubborn areas can be removed with a small, sharp knife. Medium-coarse steel (soap-free) can also be used ensure a solid electrical connection. Wipe dry and allow everything to air dry completely. To prevent corrosive deposits from forming again, coat the terminals and wiring connectors with a liberal application of dielectric grease -or even better: A silicone dielectric terminal grease.

The new battery pack also needs to be gradually "broken in". That is, run your HCF-305 no more that 2 miles on the first test run. Then completely recharge the battery pack. Run your HCF-305 no more than 4 miles on the second run, and recharge. 7 miles on the third run, 9 miles on the fourth run, 11 miles on the fifth run, and 14 miles on the sixth run. Your battery pack is now ready for hard use.

The HCF-305 should now have a maximum range of 15.5 miles on a smooth surface in open country, or 9.5 miles in neighborhood stop-and-go traffic, at 15 miles per hour.

The first test run on the HCF-305, the vehicle was driven at full speed, for about 8-1/2 miles (but don't do what I did -see above), before the heat sensor in the motor caused the circuit breaker button to fully extend out, turning off the power to the vehicle. Following the instructions of the HCF-305 Operator's Manual, the vehicle (actually, the motor) was allowed to cool off for about 20 minutes, before the circuit breaker button was pushed back into the flush (reset) position, and the HCF-305 was turned on and driven home, about a mile away, with power to spare.

Before the second test run, a digital speedometer/odometer was installed to provide greater accuracy. A digital odometer is especially useful when operating a Light Electric Vehicle, as it provides a clear, precise display of the remaining mileage on your vehicle.

* Here are the results with the PowerSonic battery pack (on a smooth, paved surface, and with the modified bicycle trailer in tow):

Maximum speed: 15mph (24.2kph)

* Maximum Range (on a smooth surface, in open country):

15.5miles (24.9 kilometers) @ 15mph (24.2kph)

31 miles (49.9 kilometers) @ 9.2mph (14.8kph)

46.5 miles (74.8 kilometers) @ 4.6mph (7.4kph)


* Maximum Range (in neighborhood stop-and-go traffic):

10 miles (15.3 kilometers) @ 15mph (24.2kph)

20.5 miles (30.6 kilometers) @ 9.2mph (14.8kph)

31 miles (45.9 kilometers) @ 4.6mph (7.4kph)

* It's important to note here that the above are MAXIMUM ranges. That is, I ran my electric vehicle, at full cruising speed, until the electronic controller shut it down, and then carefully noted the miles. This is not recommended, if you want your battery pack to enjoy a satisfactory lifespan. Doing so (driving your vehicle hard, until it just crawls back home) is commonly known as "batterycide".

* Running the above mileages, per charge, your battery pack will last about 1,000 miles / 120 charge cycles. But simply running your vehicle at 2/3 the above mileages, maximum (but still cruising at 15mph), will double the lifespan of the battery pack, to 2,000 miles / 240 charge cycles, which I've found to be a better trade-off.

* It's also important to note that the average annual temperature of where I live and drive my electric vehicle is 58.6 degrees Fahrenheit (= 14.8 degrees Centigrade).  If your average annual temperature is higher, then expect your battery pack to have a somewhat shorter lifespan.  If your average annual temperature is lower, then expect your battery pack to have a somewhat longer lifespan.

The above mileage is at an ambient operating temperature of 70 degrees Fahrenheit. Driving in cold weather can reduce range, and driving in warm weather can increase range as follows:

100 degrees Fahrenheit: 128% range With dual LED headlights on: 115% range

90 degrees Fahrenheit: 119% range With dual LED headlights on: 107% range

80 degrees Fahrenheit: 109% range With dual LED headlights on: 98% range

70 degrees Fahrenheit: 100% range With dual LED headlights on: 90% range

60 degrees Fahrenheit: 87% range With dual LED headlights on: 78% range

50 degrees Fahrenheit: 74% range With dual LED headlights on: 67% range

40 degrees Fahrenheit: 61% range With dual LED headlights on: 55% range

30 degrees Fahrenheit: 47% range With dual LED headlights on: 42% range

* Increase above ranges 75% if PowerCheq electronic balancing modules are installed in the battery pack (see PowerCheq page in this Instructable).

One possible complication, though, is the HCF-305 motor overload sensor. While this valuable feature will prevent the motor from overheating and burning out, the sensor-activated circuit breaker, after about 4-1/4 miles of hard riding (at 15 mph) will kick in at the darndest times, such as when speeding through a busy intersection, etc.. At full speed (15 mph), the heat sensor, inside the aluminum end plate of the motor, signals the electronic controller, which makes the decision to shut down the power, at 126 degrees Fahrenheit, causing the HCF-305 to come to a complete stop. A short wait, of a few minutes, is all it takes for the motor to cool off, and the vehicle's circuit breaker can be reset.

Or, a better option: Accelerate to full cruising speed, then back off on the throttle until there is a noticeable drop in speed, then increase the throttle ever so slightly back to full cruising speed. You'll cruise like a pro. And, more importantly, you'll be able to cruise at a sustained cruising speed of about 15 mph, and the electronic controller will now allow the motor to operate at up to temperatures of 145-150 degrees Fahrenheit, without overheating the motor.

The replacement PowerSonic battery pack requires a full 8 hours to charge, before the amber charging led turns green. But a full overnight charge (12-14 hours) is highly recommended. After a full charge, each 12 Volt battery will test at 13.5-14 Volts.

Note that sealed lead acid batteries have a slightly different electrolyte, which influences the terminal voltage. If you have installed a set of PowerSonic batteries -and chosen not to break them open and add electrolyte, a full charge voltage should read about 12.8 to 14 Volts.

ALWAYS recharge your lead acid battery pack after a good run (4-1/2 to 7-1/2 miles, or more). Failure to do so can cause deterioration of the lead plates.

Also, like Ni-Cad batteries, I've read that lead acid batteries can also develop a memory. This means that after a short test run around the block, for example, the battery pack should not be recharged before storing the vehicle away. Recharging the battery pack, as such, may adversely affect the next cycle, reducing the range. I don't really worry myself with this possibility, but posted it as a precaution.

So far, the results from the new battery pack have been dramatic. Costing about $ 260.00 American dollars, which included shipping (but the price is going up in 2009), I feel that these batteries will provide a compact, yet powerful and reliable high-rate discharge system to power the HCF-305's 600 watt motor.

My HCF-305 is now being run on as many errands around town as possible, to find out how tough these improvised batteries really are. Occasional checks of the battery electrolyte levels required only a light "topping-off" of one cell, of one battery only, with electrolyte (with these batteries, don't ever use distilled water for topping off). The batteries in the battery pack were also occasionally rotated, from front to rear, to distribute wear (if any) evenly on the batteries.

I've been asked:  How does one know when the electric vehicle battery pack has reached the end of its lifespan?  The answer is that the performance of the vehicle simply, and quickly, degrades to half the range, after a year or two of service.  Lead acid battery packs, in electric vehicles, are usually replaced when the capacity drops to 80% (80% capacity = 1/2 the range of a new battery pack) or less.  To fully understand the usefulness of an old battery that is now at 80% capacity:  Mark out the "21 Amp Hour" rating on the outside of the battery and write in "16 Amp Hour" and treat the battery accordingly.  But my "discarded" 12VDC sealed lead acid batteries (but flooded) are more than welcome, joining up with the old battery pack of my wind generator  -or sun tracking solar panel, where they will continue to enjoy years of satisfactory service.   

The purist may choose to charge their custom battery pack, using four 12 Volt chargers, one for each battery, to ensure a "balanced battery pack". But this is unnecessary with the HCF-305, since the batteries were ordered from the supplier, specified as a matched set. Also, the HCF-305 electronic controller never allows the battery pack to discharge below 40 percent, so a possible weak battery in the pack becomes less of an issue. And periodic rotation (done every time the battery electrolyte level is checked) of the battery arrangement in the pack tends to balance out possible system stress on any one battery. The four 12 Volt battery pack arrangement is also defined a "low voltage traction pack", which is not as maintenance-critical as the newer, higher voltage, multiple battery packs in the newer electric cars on the market. A "balanced battery pack" is essential for a lithium-polymer powered radio controlled model airplane, but not for a pack of four lead acid batteries, carefully protected by the HCF-305 electronic controller.

But I am building a lightweight 12 Volt fast charger, which will be permanently mounted on the vehicle, to take advantage of the locally proposed electric vehicle infrastructure, to double the operating range of the vehicle. And it will require four 12 Volt chargers, in order to carefully control the fast-charge process.

The new battery pack will soon be wired with a fuse, on each battery, so that a short-circuited battery won't destroy the entire pack. The OEM battery pack wiring harness, oddly, is not fused. Also, the series-parallel arrangement pushes the limits of what an amateur should really attempt on these sort of projects, so stay posted for specific wiring details, complete with photos.

Powering your HCF-305 / Light Electric Vehicle with other types of batteries:

The HCF-305 comes equipped with small, compact sla-agm (sealed lead acid - absorbed glass mat) deep cycle batteries. The problem is that, while deep cycle, the standard issue WP20-24E batteries are not designed as "High-Rate" batteries, in that they are not designed to survive the heavy discharge demands of a 600 watt motor.

But with the new breed of high-rate sealed lead acid batteries, there's really no better class of battery for the task. Sealed lead acid batteries first appeared in the 1970's, and have slowly improved and evolved into today's SLA's, which have twice the capacity, for their size, than those of the 1970's and 80's. SLA/AGM's are now a better choice than lithium-ion batteries. Even if not used, an electric vehicle, equipped with sla-agm batteries, will lose only about 8% of its battery charge, per month. And even that tapers off to only about 20%-30%, total, over a 6 month period. But breaking open and flooding the battery pack with electrolyte will cause the batteries to behave like typical flooded lead acid batteries, and battery pack will self-discharge almost 1% per day.

Traditional flooded lead acid - deep cycle golf cart batteries are just too large and cumbersome.

Traditional flooded lead acid automotive batteries are not designed to survive the deep cycle applications required by electric powered vehicles. Using standard automotive batteries, in the HCF-305, will do permanent damage with each cycle, destroying them after about 25 run/charge cycles.

Deep cycle "marine" lead acid batteries (both flooded and absorbed gass mat) are not suitable for powering electric vehicles. Marine batteries have an internal design that is somewhere between that of a deep cycle golf cart lead acid battery and a traditional flooded lead acid automotive battery. The problem is that the initial performance will seem spectacularly successful -until the battery pack finally dies after about 50 run/charge cycles. But, one real advantage of using marine batteries, is that the harbor masters, in many marinas, will freely give you their surplus used marine batteries. The batteries will work, but are just tired, and not up to full capacity. Not a bad deal for someone on the cheap.

Sealed lead acid - gel batteries are now making their way into electric powered "fun" vehicles. Sealed lead acid absorbed glass mat batteries are sometimes mislabeled "gelcells" -which they're not, but creates to the confusion. But, like most compact sla-agm batteries, compact gel batteries cannot survive the rigors of 500 watt and 1,000 watt motors. And, more importantly, having an electrolyte in a gel state, they cannot be tampered with and effectively serviced by the handyman. Sla - gel batteries are, essentially, disposable batteries.

And don't be tempted to install a pair (or a four-pack) of readily available Fisher-Price Power Wheels 12 Volt, 9.5Ah batteries (wired in series) -or a pair Peg Perego 12 Volt, 12Ah batteries. Although a reliable, long-running power source for childrens' toy cars, these types were designed to handle only dual 20watt motors, geared down to run at 3 or 4 mph. Running these through a 600watt HCF-305 motor will quickly destroy them.

So, if one wants to power their light electric vehicle with lead-acid batteries, it appears that compact sealed lead acid absorbed glass mat batteries, with after-market electrolyte added, are the best bet for powering the vehicle. With a 1:4 weight ratio (battery pack : total vehicle), this is approaches what a good electric vehicle should be.

Nickel metal-hydride battery packs (made of multiple 1.2 Volt cells) are still too problematic for mobility scooter applications. So are nickel-cadmiums. And an electric vehicle, equipped with NiMH, or Ni-Cad batteries, if not used, will lose almost 10% of its battery charge, per day!

Lithium-ion batteries are sometimes used in cost-is-no object projects, to appear high-tech and gain instant credibility. But in fact, the only "advantage" is that it would cost about an extra $ 1,000 American dollars to outfit your HCF-305 with a set of lithium-ion batteries, and they would still be the same size, same weight, and same 40 Amp capacity. But one little-known characteristic of Lithium-Ion batteries is that they just can't tolerate a fast discharge rate -especially the demands generated by an electric vehicle.

Also, the OEM electronic controller on the HCF-305 would need to be replaced with a custom unit, since the lithium-ion battery pack voltage drops dramatically during normal discharge, and the OEM electronic controller, sensing a low voltage, would shut down the vehicle prematurely, with less range than the standard lead acid battery pack would produce.

The same applies to the new lithium-polymer batteries -except that they do handle fast discharge rates quite well. False hopes have been generated by the fabulously successful lithium-polymer batteries now used in many high-performance radio-controlled model race cars and model aircraft. But the transition of lithium-polymer power into electric powered vehicles has just not been cost-effective. And, quite frankly, not even effective.

Fuel cell batteries, while promising, are too fragile, too expensive, and still under development for light electric vehicle applications. And even, if and when, they are developed and marketed, there is, at present, no infrastructure for readily fueling electric vehicles.

LiFePO4 (Lithium Iron Phosphate) battery technology just may change forever the light electric vehicle industry. The technology is here, and, if you shop around, the cost is now about 1.5 to 2 times the cost of an equivalent set of SLA batteries.

The development of truly new batteries for electric powered vehicles has been painfully slow and stubborn, with with real breakthroughs just now starting to happen. 

a couple of years ago, I upgraded my HCF-305 with a 25-Volt 40-Amp-Hour Lithium-Iron Phosphate battery pack, which has doubled the range -without overloading the electronic controller. The same size as my OEM battery pack, the new-fangled Lithium-Iron Phosphate battery pack, at 25 pounds, weighs only half as much as the lead-acid battery pack.

Another provocative -and fun, idea is investing in a 24 Volt, 450 Watt wind generator and 110W solar panel combo, a $ 1,500.00 package that also includes tower hardware and an electronic charging panel. http://www.home.earthlink.net/~hcf-305userforum

Step 2: PowerCheq Electronic Battery String Equalizers Increase the Mileage of the Battery Pack By 75 Percent!

PowerCheq is a real-time, electronic battery balancing system that equalizes and maintains batteries during charge, discharge, and while sitting idle.  By continuously equalizing individual batteries, within a string, batteries are properly maintained and kept at the same state of charge.  Operation during charging ensures that all batteries will receive a full and equal charge, thus preventing undercharging / overcharging.

An excellent demo as to how the device functions can be found at:

http://henot.longrine.fr/EV/PowerCheq.swf

As mentioned earlier, the four - 12Volt, 21Amp PowerSonic PSH-12180NB-FR batteries are wired, in pairs, in series, and then parallel wired, to produce a 24 Volt, 42 Amp battery pack.

But it is not well known that, in such a battery pack, the two batteries, attached to the final positive wire to the electronic controller, discharge much faster than the other two batteries, attached to the final negative wire to the electronic controller.

This creates a serious imbalance that not only leaves unused power, in the two negative-end batteries, but also reduces the lifespan of the over-all battery pack  -even with periodic battery rotation.

My initial plan was to wire in a cumbersome, heavy-duty electric switch, with eight wires from the batteries entering one side, and two wires exiting the other side, to the electronic controller.  The switch would be used halfway through the vehicle run, for the return trip home.  The sequence of the battery pack would be completely rearranged (aka battery rotation) and, I figured, would increase the range of the vehicle by 25 percent and extend the overall life of the battery pack.

Yet, at the same time, I heard about the PowerCheq battery string equalizer, which seemed to be far more user-friendly  -and efficient.  But the reviews on the internet seemed less than enthusiastic.  And the manufacturer (PowerDesigners) had removed the device from their website (www.powerdesignersusa.com).

After reading about the low performance gains PowerCheq users reported, I feel that the issue is that the PowerCheq device, which was actually developed for electric wheelchairs and mobility scooters, was, in fact, purchased and installed in full size electric vehicles.  And, as could be expected, the performance gains were, at best, meager, due to sheer size of the batteries.  In short, a PowerCheq battery string equalizer will improve the performance of a 75 Amp-Hour battery, but common sense dictates that only so much power can be transferred through the thin 16awg-18awg PowerCheq wiring.

But things change when the PowerCheq is used with 21 ampere-hours (AH) batteries:  The revolutionary device functions at its best!

The PowerCheq module interconnects the two 12V batteries connected in each 24VDC series string, in the battery pack, creating a bi-directional energy transfer path between the batteries.  The module intelligently equalizes batteries during charge, discharge, and idle periods, keeping them properly maintained at the same state of charge  -critically important to battery life and range of the vehicle battery pack.

Only two PowerCheq devices were needed, as the simple parallel wiring of the battery pack naturally works to balance the two 24VDC battery strings.

Voltage checks, as well as amp-load tests, have been performed:  After charging, halfway through errands, and after returning home, and the battery pack is perfectly balanced at all times, with the LED indicator lights on the PowerCheq modules constantly blinking on and off, busily at work.

Each module, operating at 85 percent efficiency, transfers up to 2 Amps, while consuming only about 5mA current from the batteries.  After charging, the 6 watt float charge of the vehicle charger is raised to a 7 watt float charge, by the PowerCheq devices.


More information about the device can be found at:

www.evsource.com/tls_powercheq.php

www.broadenedhorizons.com/powercheq.htm#specifications


Here are the results (on a smooth, paved surface, and with the modified bicycle trailer in tow) with the modified PowerSonic battery pack (broken open and flooded with standard battery electrolyte solution) with two PowerCheq battery string equalizers installed:

Maximum speed: 15mph (22.5kph)

* Maximum Range (on a smooth surface, in open country):

27 miles (43.5 kilometers) @ 15mph (24.2kph)

54 miles (87 kilometers) @ 9.2mph (14.8kph) *This mileage has been calculated  -not road tested.

81 miles (130 kilometers) @ 4.6mph (7.4kph) *This mileage has been calculated  -not road tested.

* Maximum Range (in neighborhood stop-and-go traffic):

19.2 miles (26.7 kilometers) @ 15mph (24.2kph)

35.8 miles (53.5 kilometers) @ 9.2mph (14.8kph) *This mileage has been calculated  -not road tested.

54.2 miles (80.3 kilometers) @ 4.6mph (7.4kph) *This mileage has been calculated  -not road tested.

The above mileages are for an ambient operating temperature of 70 degrees Fahrenheit.

 The above results are preliminary, as the actual mileages were done under less than optimum operating temperatures (Fall season, ~53 degrees Fahrenheit) and then calculated to the projected 70 degrees Fahrenheit (normal operating temperature), and will be fine-tuned over the next few months.

* It's important to note here that the above are MAXIMUM ranges. That is, I ran my electric vehicle, at full cruising speed, until the electronic controller shut it down, and then carefully noted the miles. This is not recommended, if you want your battery pack to enjoy a satisfactory lifespan. Doing so (driving your vehicle hard, until it just crawls back home) is commonly known as "batterycide".

When the green led is flashing on the PowerCheq unit it simply means that the device is working hard at keeping the batteries in perfect balance, while charging, or while the vehicle is running.  Warning:  The flashing green led ceases to operate and the solid red led lights up when the batteries discharge below a minimum voltage.  At that point, the PowerCheq device ceases to balance the batteries and the vehicle should be either recharged on the spot, or pushed home.  Driving the vehicle further will cause permanent, long-term damage to the battery pack, shortening its lifespan.  

Running the above mileages, per charge, your battery pack will last about 1,000 miles / 120 charge cycles. But simply running your vehicle at 2/3 the above mileages, maximum, will double the lifespan of the battery pack, to 2,000 miles / 240 charge cycles, which I've found to be a better trade-off.

That said, here are my most recent notes, to achieve maximum range, as well as suitable performance:

Maximum Recommended Range At 15mph Cruising Speed:

   100 degrees Fahrenheit: 17.0 miles .... With dual LED headlights on: 15.3 miles

     90 degrees Fahrenheit: 15.8 miles .... With dual LED headlights on: 14.2 miles

     80 degrees Fahrenheit: 14.5 miles .... With dual LED headlights on: 13.0 miles

     70 degrees Fahrenheit: 13.3 miles .... With dual LED headlights on: 12.0 miles

     60 degrees Fahrenheit: 11.6 miles .... With dual LED headlights on: 10.4 miles

     50 degrees Fahrenheit: 9.8 miles ..... With dual LED headlights on: 8.9 miles

     40 degrees Fahrenheit: 8.1 miles ..... With dual LED headlights on: 7.3 miles

     30 degrees Fahrenheit: 6.3 miles ..... With dual LED headlights on: 5.6 miles

These revised mileages are not what I like, but are completely satisfactory for local errands.  Only time will tell if the lifespan of the battery pack is truly doubled.  There is another advantage in these reduced mileages in that the battery pack can truly be charged overnight (9 hours), with the modest OEM battery charger, and the vehicle will always be ready to run again the next morning. 

When I purchased the PowerCheq devices, I figured that the devices would increase the range of the vehicle by 25%.  But the tiny modules actually increased the range of the vehicle by 75% to 100%.  And the humbling thing about it all is that I have no clear idea as to why this happened, yet.

Anyway, the gold standard:  A full run, on a smooth surface, in open country (no stop-and-go) @ 70 degrees Fahrenheit, will be done as soon as proper weather permits.  But the final mileages are actually expected to be slightly better. 

I have to admit that I have been quite surprised with the above results and waited over a month, after numerous test runs, before reporting my results to the local Electric Auto Association.  And it's also been fun running errands into the next town.  It seems that the age of the practical light electric vehicle is at hand. 

PowerCheq Electronic Battery String Equalizers (12V Module: #401-PCHQ-12V-2A) can be purchased, for $ 58.99 each at:

www.evsource.com/tls_powercheq.php

Step 3: 24V 40AH LifePO4 Battery Pack!

Picture of 24V 40AH LifePO4 Battery Pack!
24 Volt LiFePO4 Battery Pack and Charger.jpg
24 Volt LiFePO4 BMS.JPG
24 Volt LiFePO4 Battery Pack and BMS - 2.JPG
24 Volt LiFePO4 Battery Charger.JPG
Off-the-shelf technology is changing so rapidly that as soon as I research, road test, and fine-tune a high-performance deep cycle lead acid battery pack  -it becomes obsolete!

Specifically, the development of affordable ($ 450 + shipping), drop-in-and-go Lithium Iron Phosphate (LiFePO4) battery packs, complete with its own battery management system and quick charger.  And this has all happened years before I thought it possible.

The reason why a LiFePO4 battery pack excites me is that it is a true high rate battery (can take a heavy discharge load) and it has a relatively flat discharge curve, so that existing electronic controllers, designed for deep cycle lead acid batteries, will work quite well with the new LiFePO4 battery pack, without having to be re-programmed.     

The technology is improving so rapidly, that I am reluctant to specify any brand names, as performance, quality, and prices are expected to improve in the next few years (months?).

But an excellent first stop is www.ebay.com

Search for "24Volt LiFePO4 Battery" to bring up the latest vendors.

I would buy and install a  LiFePO4 battery pack right now, except my deep cycle lead acid battery pack, with PowerCheq electronic battery balancers, is expected to last for two years.

Note:  The maximum discharge rate of these new LiFePO4 battery packs range from 2C to 10C, depending on brand name.  And I recommend the high rate 10C units.

The “C” rating is the maximum safe continuous discharge rate of a pack. If you see 10C on a battery pack, it means it can be discharged at 10 times that pack’s capacity. “Capacity” refers to the Amp-Hour rating of the battery, which will be listed as a number followed by Ah (40Ah, for example).

There’s the easy way to find your battery’s Maximum Discharge rate:  Just multiply the number from the “C” rating by the pack’s capacity.

Here’s an example, using a 24 volt – 40Ah - 10C battery pack:

40 Amps x 10 = 400 Amps Maximum Discharge Amperage

Divide by 2 = 200 Amps Rated (continuous) Discharging Amperage

This means that you can safely draw up to 200 Amps continuously from that 24 volt – 40Ah - 10C without doing damage to your battery pack, although I would still not want to put anywhere near that load on the battery pack.

 A 24 volt, 40Ah LiFePO4 battery pack will also provide more range than a 24 volt, 40Ah lead acid battery pack, because it can discharge far more in a typical discharge cycle, to levels that would damage a typical deep cycle lead acid battery pack.  So expect up to 50% more range.

LiFePO4 battery packs weigh only about half the weigh of equivalent sealed lead acid battery packs, and are about half the size of equivalent sealed lead acid battery packs.

LiFePO4 battery packs are not as affected by low temperatures, in contrast to a typical deep cycle lead acid battery pack, which provides only half the range, at 30 degrees Fahrenheit, than it provides at 70 degrees Fahrenheit. 

LiFePO4 battery packs have a useful life (down to 85% capacity = 69% range) of 1,000 charge cycles, in contrast to a deep cycle lead acid battery pack (with electronic battery management) that has a useful life (down to 80% capacity = 50% range) of 250 charge cycles.

This technology naturally implies that larger, affordable multi-passenger cars and utility trucks will be available to the general consumer, soon.

Stay posted. 

Step 4: Modifying the rake angle of the original HCF-305:

The rake angle of the original HCF-305's front wheels are backwards!

Look carefully at any bicycle, or motorcycle, and you'll notice that the front wheel slants well forward of the handlebars. A typical motorcycle, for example, has a positive rake angle of about 30 degrees. The rake angle of a well designed bicycle, or motorcycle, provides inherent stability, so that the rider can easily ride without any hands on the handlebars, yet continue in a straight line.

But with the HCF-305, the problem can be corrected. The engineer who designed the HCF-305 seems to have provided for a good, positive rake angle, but, somehow, down the line, the front wheel suspension was reversed (backwards). A quick examination underneath will reveal that the front wheels need to be removed, leaving the brakes in place on the wheels. Both wheels are held on with standard right-hand thread bolts, with 17mm heads. But be sure to unscrew the tiny lock-screw, on the steering arm, first. Then the entire front swing arm / headset bearings / steering arm joint, on each side, needs to be removed and switched left and right with each other (leave the shock absorbers in place on the frame). The steering arm, underneath the headset bearings, (also holds the wheel axle bolt), will need to be installed upside down this time.

But first, the original M10-1.5 pitch headset bolt needs to have an additional 11mm of thread cut into it to properly fit into the now upside down steering arm (a simple handyman project). The brakes (actually a drum, mounted permanently on the wheel hub, encircled by a removable steel compression band), are designed to primarily stop forward motion, so will have to remain on their original sides and orientation. After the adjustments, the front wheels will extend forward an inch or two, and the steering tie rods will now assume a more natural, horizontal position. My HCF-305 now glides over bumps and rough roads much more smoother. Changing the HCF-305's front wheel suspension to a proper rake angle will reduce stress on the steering headset bearings, so that they will now absorb bumps, at the angle they were designed to do, and pass the shock of the bumps directly to the shock absorbers, which will also now be in a better able to dissipate those impacts.

Modifying OEM 22" handlebar to a 29" Longhorn handlebar:
The HCF-305, being a "scooter", does NOT have pack and pinion steering. This means, that at full cruising speed, the HCF-305 experiences a slight loss of steering control, especially when riding over rough paved surfaces. I initially planned to install a hydraulic steering dampener in the undercarriage, but simplicity dictated that adding 4" extensions to each end of the handlebars should provide the proper leverage, a well as a natural steering dampener effect.

The steering system of the HCF-305 is well built, tight, and secure. But the turning radius is just too tight for comfortably running the vehicle at full cruising speed.

I machined down two 7/8" diameter hardwood dowels, 7-1/2" long: 4" @ 7/8" diameter + 3-1/2" @ 3/4" diameter. The inside of the handlebars were degreased and the wooden extensions were glued into place and then marine varnished.

But the above steps are not a cure-all. My HCF-305 now leans slightly out of the turn, and tends to slightly veer left and right, from a straight line, while driving, but the the over-all handling of the vehicle is definitely improved.

So feel free to alter the front-end suspension, but at your own risk.
jrjohnwood10 months ago
I have been following your battery upgrade and wish to ask how are they performing now? I am getting ready to order 4 very similar style of AGM SLA batteries to use on a front wheel 1000 watt bike motor, but since you have the ONLY post of adding extra electrolyte and bypass the pressure check valve by pin pricking the cell caps, I am concerned to their longevity. Would sure hate to crater a brand new set of batteries, you know. Just wondering is all, and congrats on a really nifty setup!
shastalore (author)  jrjohnwood1 month ago

jrjohnwood: I apologize for the delay, but your comment was buried in a secondary page of my instructable, and I just saw it. My 24VDC, 40 amp-hour flooded sealed lead-acid battery pack will function for about 150 charge cycles = about $ 0.15 per mile for battery pack expense. In comparison, my same 1-passenger electric vehicle cost about $ 0.25 per mile tire wear expense.

As for the longevity of the batteries: After being retired from my electric vehicle (at 80% capacity = 50% range) they still have years of use with my portable homemade wind generator and portable homemade sun tracking solar panel. I periodically do a 12 Volt Amp-Load test on each old battery and reference a chart to assign each battery a revised (and lower) Amp-Hour rating, just to always know the useful capacity of each battery.

As for running your 1,000 Watt motor with a 24 Volt, 40-42 Amp-Hour battery pack, it'll probably overload your battery pack, even if flooded and electronic balancing modules added to the batteries. You'll probably need a 24 Volt, 70 Amp-Hour battery pack. But you never stated the rated Voltage of your 1,000 Watt motor, so I'm just guessing.

shastalore (author)  jrjohnwood10 months ago
My flooded (and pin-pricked cell caps), and electronically balanced, AGM-SLA batteries worked exceptionally well, and I eventually retired them in favor of a LiFePO4 replacement battery pack.

But these retired, old lead-acid batteries are still more than welcome with my portable wind generator and portable solar panel applications, for years of use. That's the long-term advantage of flooding AGM-SLA batteries.

So don't worry that you would "crater" a brand new set of batteries. AGM-SLA batteries are already "electrolyte-starved," that is, the AGMs are 99% full of electrolyte, so simply filling the empty air spaces in the battery cells with standard electrolyte solution will not any damage what so ever.

Granted, I'm the ONLY post on the internet advocating breaking open and flooding AGM-SLA batteries (and voiding the warranty), but I'm also the only post on the internet in numerous, diverse applications, not hesitating to point out the flaws in many main-stream, but unexamined, beliefs, and providing my own detailed, tried-and-proven solutions.

But I really want to point out that I am no longer an advocate of lead-acid batteries, for electric vehicles. A LiFePO4 battery pack, that will fit snugly into your existing battery compartment, will weigh half as much as your present lead-acid battery pack, will provide 3 to 4 times the range of the lead-acid batteries, and will last at least 4 times longer than the OEM lead-acid battery pack, if not more.

I purchased my 24-Volt, 40-Amp-Hour LiFePO4 battery pack, from V-Power, on ebay, several years ago, and, amazingly, it shows absolutely no signs of decline. And am so satisfied with it that I no longer advocate lead-acid batteries for electric vehicles.

souixzan1 year ago
hi
i have a zap xebra under the flat bed zap has 7 12 volt batteries
that are wired in two series. in order for the charge
to be evenly distributed it used a powercheq pchq-12v-2a.
these little boxes with three wires + and - and ground
are bi-directional and equalize the charge so that none
are over or undercharged. this circuit has been broken
and the batteries now read: dead, overcharged, dead, overcharged, et al.
everything worked well before this cycle was broken.
now, all i really need is another of these little boxes (or similar component)
to re-complete the cycle. can u help? i cannot find these powercheq's anywhere
- the company who used to manufacture them stopped making them 4 years ago.
thanx so much for your time and consideration i am learning as i go and glad of it!
suzia aufderheide
ashland, oregon
shastalore (author)  souixzan10 months ago
Hello Suzia,
The PowerCheq modules were designed for electric wheelchairs, for 12-Volt 21-Amp-Hour maximum size batteries.
Unfortunately, many full-size electric vehicle owners have installed these PowerCheq modules on their 12-Volt 100-Amp-Hour batteries, and are frustrated to discover that there is very little difference in performance.
But a quick glance at the thin wires on the PowerCheq modules, compared to the heavy, gnarly 12-Volt battery cables, should make it obvious that those tiny modules can't possibly transfer or divert enough current to keep their battery pack balanced.
And I don't know of any tried and proven, high capacity electronic modules on the market to suggest for 100-Amp-Hour batteries.
But to install a new lead-acid battery pack will cost you about $1,500 to $2,500, depending on the brand and type, and that's not including labor. And that does not include essential electronic battery balancing modules between each battery.

What I do suggest is that you check out ebay, and search for LiFePO4 battery packs, although you will probably not find 72-Volt battery packs. But contact some of the highly rated vendors and approach them about the possibility of one of their staff engineers putting together a custom LiFePO4 replacement battery pack, complete with charger and electronic battery balancing module, for your Zap Xebra. The advantage here is that the Zap Xebra OEM electronic controller will not have to be reprogrammed for the LiFePO4 battery pack.
Their price for all this may shock you, until you revisit the true costs of a lead-acid battery pack.

A LiFePO4 battery pack, that will fit snugly into your Zap Xebra battery compartments, will weigh half as much as your OEM lead-acid battery pack, will provide 3 to 4 times the range of the OEM lead-acid batteries, and will last at least 4 times longer than the OEM lead-acid battery pack, if not more.

I purchased my 24-Volt, 40-Amp-Hour LiFePO4 battery pack, from V-Power, on ebay, several years ago, and am so satisfied with it that I no longer advocate lead-acid batteries for electric vehicles.
quote "And another warning: Don't be tempted to build a custom 24 Volt battery pack that exceeds 40-42 amps. Doing so will quickly burn out the electronic controller"
why will this burn out the controller? i thought it would just add range as the controller will only draw the amps it needs as if this were true then replacing a 2c lifepo4 battery with a 10c battery would this not cause the same damage?
shastalore (author)  oldskoolhead1 year ago
Electronic controllers are rated, and chosen, on a number of factors, such as to the maximum Amp-Hr battery pack they are designed handle.

And the OEM HCF-305 electronic controller is not exactly a heavyweight in this arena. To further illustrate, you may have noticed that kids electric scooters have much smaller controllers, while electric motorcycles have much larger controllers -designed to handle much larger battery packs and loads (motors).

A few HCF-305 owners have emailed me to complain that their high performance mobility scooter no longer works. And after reviewing their list of symptoms, a custom, oversize battery pack is often the culprit (such as a 80 Amp-Hour pack). And these unique OEM controllers need to be especially valued, since they are becoming more difficult to replace, as they handle numerous automatic functions throughout the vehicle, besides the basic speed controller functions of the 24V electric motor.

The electronic controller mentioned in this article is not re-programmable, although one HCF-305 owner is attempting to do just that, but I haven't heard anymore from him in over two years. The main barrier to this is that the internal circuit board of the OEM device is injected, at the factory, with a super-tough glue that resists any attempts to chemically dissolve it, and open the circuit board for tampering.
Thanks for the great write up and advice clearly you did your homework and it paid off!
FrozenIce2 years ago
way too many words on one page...
agreed
epierce2 years ago
Thanks for the info Shastalore! My solar charged trike has done 1000 miles in 10 months but has had to be charged old school style lately.
12 volt lead acid batteries don't top out at 12.6 volts, or even all that close really. They actually top out at 13.8-14.2 volts(when newer of course)This extra voltage used to be called "float voltage"(not sure if they have a new name fir it now or not) But to get rid of that
'float charge" just run the lights for a few seconds-1 minute. then you will be back to "normal full charge.

Also heat affects batteries very little nowadays, unless you have a battery installed in a hot or cold climate and then move to the opposite climate. Batteries like gasoline are designed for the normal outside temperature they are expected to run at.(example)batteries made for use in very hot vlimstes have fewer plates that are thicker, this allows the lead to withstand the extreme heat better but reduces the cca's. Batteries made for extremely cold climates have thinner but more plates increases the cca's but causing no problem with lead deformation due to cooler temps. You wanna see a battery die in a real hurry? Buy one from a desert location and then move to a place like new york, or vice versa.

I found a good explanation of the effects of temps on battery life on the net and will repost it here.

"Battery capacity (how many amp-hours it can hold) is reduced as temperature goes down, and increased as temperature goes up.
...
Even though battery capacity at high temperatures is higher, battery life is shortened. Battery capacity is reduced by 50% at -22 degrees F - but battery LIFE increases by about 60%. Battery life is reduced at higher temperatures - for every 15 degrees F over 77, battery life is cut in half"

Now this is usually not a real problem since the effects on batters are not a one shot deal. In other words if your battery spends 6 months a year at -22F you gain a 60% increase in battery life.But if you spend the other 6 months of the year around 100 degrees you will lose about 60% of battery life, however it will average out and the battery will last about the same as if it was at 77 Degrees all year long.
lobo0x74 years ago
wow shastalore! i am amazed of your deeep knwoledge on batteries. good work, thanks for sharing i am trying to put together some sort of e-vehicle and you are the number one in my list of batterie gurus... can i make you a couple of questions? one is: does it matters to mix diferents sizes (amps) of batteries as far as de volts are the same? and diferents voltajes? the second one is a bit more general: wich configurationn will you recomend for a ultralight e-motorcicle (or a heavy bike) in order to have the better range possible (it will be used mostly in town and in small road trips, so hi-speed is not a must)? i meant basically motor? watts? volts? (i still thinking in mantain the pedals like in a bike specially for avoid the motorcicle treatment by the road police), so, hub motor? and wich batteries do you recomend in order to have decent range without beeing screwd by the prices of high.tec batteries? it was a lot more than 2 questions, after all thanks again
shastalore (author)  lobo0x74 years ago
The batteries in your electric vehicle should be a matched pack. That is, order the batteries you need at the same time. All should be the same size and capacity. And, after receiving the shipment, be sure to fully charge, and then test each individual battery with an amp / load test. A simple $ 30.00 amp / load test meter can be purchased at your local auto parts supplier. Check out my webspace link for the details of using this device, as documentation and technical info is notoriously absent with these inexpensive devices. And such an amp / load test will destroy a small SLA/AGM battery. A good rule of thumb is that 1 out of 10 (1 out of 12, in my experience) sealed lead acid batteries, from the factory, will amp / load test as "bad", or defective. I'm an advocate of high-rate, sealed lead acid, absorbed glass mat batteries, for light electric vehicles. They are very tolerant of misuse and abuse. Other more exotic batteries are fraught with problems that the new experimenter is ill-prepared to finance, problem-solve, and achieve satisfactory performance. As you seem to just be starting into experimentation with light electric vehicles (welcome aboard) I would suggest that you purchase a basic electric conversion kit (rear wheel/brushless motor hub, battery pack, controller, throttle grip), for an existing mountain bike. Try for a 48VDC system, as it has greater torque, for hills and such, than 24VDC (or 36VDC) systems. And a 500 watt motor would provide enough power to go just about anywhere, although a 250 watt motor would work just fine, if you live in a community with no hills. I suggested a mountain bike, as I did just such a conversion, about 15 years ago, by mounting a 2hp "chicken power" 2-cycle motor inside the bike frame, above the pedals. I replaced the pedals with foot pegs, removed the chain and free wheel gears (from the 26" rear wheel) and attached a half-gallon fuel tank along the upper, horizontal frame tube. The front fork had motorcycle-like shock absorbers, and a large, round 12VDC malibu halogen headlight completed the rig. The bike had a top speed of 24mph, and was street legal, in California, as long as the rider had a valid California drivers license. And the bike was a totally cool experience to ride: I sometimes passed oncoming Harley cyclists, only to have them do a quick u-turn and catch up with me at the next stoplight, thinking that I was riding a vintage turn-of-the-century "Merkel", or "Cyclone". But, to make a long story short, it's essential that all electric vehicles be designed, primarily, to be FUN. Otherwise, the performance will be just too far behind that of gas powered vehicles, for most people to tolerate their performance shortcomings. And 26" diameter wheels (fitted with street tires @ 100psi) are, according to the simple laws of physics, the most efficient size wheels to achieve maximum speed, range, and comfort from your electric bike. Anyone, who carefully thinks it through, will not purchase any of the foolishly designed (yet expensive) electric scooters with smaller diameter wheels. An electric bike, with 26" diameter wheels, will achieve about 50% more speed and range, than an electric scooter with 13.5" wheels, even though both have the same battery packs. I really don't know how the electric scooter manufacturers think that they can get away with this incredibly serious flaw. But, in China, the typical electric scooter consumer is wise to this, and will only purchase a vehicle with a minimum of 24" diameter wheels (although 26" diameter wheels would be better). In fact, if I produce a second version of my electric car, it will have 24" diameter die-cast aluminum wheels, while keeping the center of gravity the same as the original version.
all right! thanks for the advices and also for the nice story about your 2strokes bicycle conversion. i did the same long time ago, but mine was atachded to the rear weel through a friction rubber caster! that allow to keep the bicycle pedal wich, in spain, where a live, determines the legal diference inbetween a bicycle and a motorcycle, at least in those times before the european regulations. my question about teh size of the batteries is related with the position of the batts in the frame. i was thinking in have a big 12v 45 amps from a car right at the bottom of the frame to keep the gravity center al low as possible and 3 more, small ones, designed for motorcycles, on top, in order to reach the 48vots requiered. what do yo think? thanks again, sash
shastalore (author)  lobo0x74 years ago
The reason I mentioned a mountain bike, with shock absorbers in the front fork, is that in a motorcycle (or bicycle) 70% of the braking power is in the front wheel, and 30% of the braking power is in the rear wheel, if one does a controlled stop. But, in sudden stops, that ratio easily changes to 100% of the braking power in the front wheel, and almost no braking power is in the rear wheel, unless the bike has shock absorbers in the front fork (which will help keep, somewhat, a 70/30 ratio). This is critical if you use street tires, @ 100psi, for best rolling efficiency, but need to safely stop a bike that has a heavy battery pack. Also, a mountain bike frame is sturdy enough to mount a sizeable battery pack, and carry it across varying road conditions. And, as I mentioned, you should not hesitate to romanticize when designing your electric vehicle. Every effort should be made to build it, primarily, to be FUN, and zany. Otherwise, your electric vehicle will be perceived as lagging too far behind, when compared to gas powered vehicles, for most people to tolerate its performance shortcomings -including you. In fact, I see this strategy as the only thing that will prevent the demise of contemporary electric vehicles. As for mixing different sized batteries, to fit in your frame, it not only won't work, but would be dangerous. The reason I suggested a complete bike electric conversion kit is that it usually comes with several battery pack options to pick from. And you can always design your own custom battery pack, when you eventually know your rig inside and out, and feel comfortable and proficient in designing your own battery pack. 12VDC SLA/AGM batteries come in all sizes and shapes, and it would be possible to mix and match different shapes of identical Amp Hour capacity, but you would no longer have a matched battery pack. Also, electric bikes, motorcycles, and light electric vehicles all require what is called a "traction battery pack". That is, a tough battery pack that quickly discharge large amounts of current, rapidly, without burning out. And the closest battery on the market is the High-Rate 12VDC SLA/AGM battery, even though it was not designed for an electric vehicle (it was designed for emergency computer power systems). And, even then, I strongly advocate breaking open these new batteries and adding standard battery electrolyte to the cells, which complicates things, as bicycles tend to sometimes fall over on their sides (and leak battery acid!). But High-Rate 12VDC SLA/AGM's are the best available for the task, and they are, at this point, relatively few sizes and shapes available of this type.
hi, S! you are totally right in your philosophie about to keep the vehicle as fun to ride as possible. "it's essential that all electric vehicles be designed, primarily, to be FUN. Otherwise, the performance will be just too far behind that of gas powered vehicles, for most people to tolerate their performance shortcomings." yeap, and mine will be really fun fun to ride and fun to wacht, i hope. i am thinking on it as a weird mixture out 2 bikes: a good one, the front one, carrying the front suspension fork, the hydraulic brake disk, and a nice set of everything , and a second one, the scavenged one, wich will hold the motorhub rear wheel, room for the electric setup, and all the space that i think i will need, for stuff or for extra batteries due is the only way that i can extend the range, right? the idea is to make a tandem where the pasenger place is taken by an electric fellas, and allowing the room for cargo or eventually for a human passenger. it got to be strong as a rock but i can make it with a proper treatment of the lower conections inbetween the 2 bikes. i shaw a couple of designs like this in instructables, an a lot of similar conversions for 1 weeled cargo trailers, resulting in a 3 in-line vehicle. an easy adaptation to an electric pusher can by taken from this point, but i want the real thing! a very long bycicle, stable and fast as posible. light enough for still being able to move it by pedals. but capable of extend my range to at least 100 kms, being lazy with the pedals, wich means colaborate only when climbing and at the starts. i have been making some googling in sla batts and it seems to be ok for me except for one thing: heat i read that heat will kill them pretty fast, and in the center of spain we get 40C in the summer without any effort. this vehicle should withstand stayin under the sun in such conditions, wich means a few more degrees than that, due to the facts than meteo readings are taken from a thermometer protected with a shadow from de direct sunlight. this is a lot of heatand i think that this can be an issue. this is a lot of heat, wich batts do you think can be the best for very hot climas? one more question: i am a bit afraid of the treatment that you recomend specially for the leaking factor, smalls drops o streams of acid is the las thingh that i want to see in my bike, but i am still thinking in give it a try. the pictures of the batteries that i shaw did not show any clue on how to open them, they look like plastic bricks with 2 terminals emerging. so i will prefer to try first the nice way and then, if i feel like i need more of the little boxes, broke open them and flood the cells with electrolitic fluid, as you recomend. theres is any problem with this? or the treatment must to be done in a set of fresh batts? thanks!! L
shastalore (author)  lobo0x74 years ago
I already have another light electric vehicle in the works. I've accumulated a 750 watt electric motor, an electronic controller with motorcycle twist-throttle, and 3 used 12VDC batteries (from my existing light electric vehicle), for a 36VDC system. The pedals were replaced, long ago, with foot pegs. Conservatively, I expect it to have a range of about 24 miles (39 kilometers).

When designing a light electric vehicle, I urge one to plan a battery pack that will transport the vehicle, passenger, and payload, at full cruising speed, for only one hour. Too many light electric vehicles are designed with greater range (= longer cruising times), but then a larger, heavier battery pack is needed, as well as a sturdier (and heavier) vehicle, to carry the additional load. And this escalation for greater range and performance invariably creates an electric vehicle that is so heavy that it has the daunting obstacle of simply transporting itself, much less a passenger and payload. Also, are you really willing to drive more than an hour a day, doing errands?

Everything (listed above) will mount on my old converted mountain bike (with the 2hp chicken-power 2-cycle motor removed). I'll also add a fake tear-drop "fuel tank" that will actually open up as a glove box.

I'll also build a lightweight, removable side car, for hauling, or to carry an occasional passenger.

But, an important note: The mountain bike wheels will have to be replaced with a pair of diecast aluminum wheels. The side car will also require the same. The reason is that spoked bicycle wheels are designed to handle tremendous stress, but only if they lean into the turns (which is what ALWAYS happens on a bike). In short, if you build a rig of more than two wheels, with standard spoked bicycle wheels, all the wheels will warp and destroy themselves, within in a couple of weeks. They were just not designed to handle any side stresses what-so-ever. There are some spoked wheels on the market that are specially designed to handle the side stresses of a 3-wheel, and 4-wheel light electric vehicle, but proper spoke adjustment/maintenance could be a problem.

But the 3 wheeled rig you described above, with all the wheels in-line, could be built with standard spoked bicycle wheels, but the finished rig might be unwieldy, in actual practice.

Of course, I have yet to locate a set of 3 diecast aluminum (or magnesium, or plastic) wheels, 26 inches diameter. And this project has been on the drawing board for almost two years. But don't rush me, will ya.

As for your battery pack heating up in the hot climate, you could always protect it with a reflective, insulated cover (fashioned from a chromed-plastic-bubble windshield shade). But I just feel that the intense ambient heat, even in the tropics, would only enhance the performance of your electric vehicle. But you could reference the technical notes of your battery(s) and simply find out what temperature range they were designed to operate in.
KevinM4 years ago
I'm flabbergasted at your treatment of the batteries here. (wow!) Would you recommend doing this to a standard car battery? I'm wondering about mine, my van has a tendency to kill the battery somehow, and after a while it won't hold a charge from the alternator anymore. (I still have to check the voltage accross the bettery with the vehicle running) I'm thinking 'topping off the fluid' could be a solution to my problem. I'm building a desulfator for this as well, as I think it could be a factor, but still.
shastalore (author)  KevinM4 years ago
Your question is a little out of the realm of this Instructable, but I'm answering it because I have serious safety concerns: A standard automotive flooded battery is quite different from the high-rate sealed lead acid, absorbed glass mat batteries, used in my vehicle. As for your battery, the only fluid the end-user would ever add to the battery would be an occasional topping off with distilled water. NEVER top off with pure sulfuric acid. And don't top off with standard battery electrolyte solution (even though that's what is already in there). Your alternator, if properly functioning, should register 13.5 VDC to 14.0 VDC across the battery terminals, while the motor is running. If that's what you're getting, the the alternator is fine. And when fully charged, and the motor off, a good automotive battery should register at about 12.5VDC across the terminals. But that, in itself, doesn't necessarily mean that the battery has the raw cranking amps that you need. Is the battery old? Then it might benefit from a 12VDC electronic desulfator. They can be purchased for about $ 30.00, on ebay. They use very little battery power and most can be left on the vehicle, even when it's running. Don't waste your time with chemical desulfator additives on the market. Do you use the vehicle for numerous stop-and-go errands? Or do you have numerous, or high-drain 12VDC appliances on the vehicle? That could explain the short battery life. Again, an electronic desulfator may help. Also, there may be a short, somewhere on the vehicle, on wiring that is not fused. If so, turning on the key switch (short of starting the motor) may cause the battery to quietly boil inside, indicating just that. Also, check with a good mechanic, about the brand names of good, reliable batteries on the market. It your battery woes are from heavy use and demands on the battery, they will be able to recommend special high capacity brands, of the same size and dimensions. They'll also be quick to point out that that some of the cheaper brands are just false economy. There are other unorthodox ways to rejuvenate automotive batteries, but they're messy, dangerous, environmentally unsound, time-consuming, and I'm not going to go into them here. I hope this helps. Good luck.
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