## Step 6: Batteries

This motorcycle is powered by four off-the-shelf batteries. They are Optima Yellow-Tops, rated at 55 amp-hour capacity, and cranking current of nearly 900 amps. They are AGM - absorbed glass matt. That's a style of lead-acid battery that is sealed up and the electrolyte is soaked into coils of fiberglass matting. They cannot leak, spill, or slosh around.

While there are other types of batteries available, this seemed to be the best combination of price and performance for my project. "Flooded" lead-acid batteries are really not acceptable for a motorcycle. Besides being challenging in adding water, the movement and possible tipping-over of a motorcycle would not be good for flooded batteries.

Sealed lead-acid batteries (VRLA) would also be fine, as would gels. However, neither of those can crank the power as well as an AGM can, which is what gives the cycle good acceleration. Lithium batteries are excellent for weight, capacity, and power, but are currently only for those with higher budgets. If you use lithium batteries, everything else about the project is the same, except for a different battery charger and a battery management system.

Figuring Range
Going back to some simple math, we can get an estimate of motorcycle range. I have four batteries, each of which is 12 volts, but they are wired up in one series string of all four of them, so it's really 48V in total.
The batteries are rated at 55Ah.
So, in theory, 48V x 55AH = 2640 watt-hours capacity. 100 watt-hours per mile is a typical ball-park number for energy consumption per mile on an electric motorcycle. (Of course that does vary by weather, speed, riding style, etc.) But this is just a rough estimate.
2640/100 = 26.4miles
Just a real rough estimate, but it's good enough to say "Will this vehicle meet my needs? Will it perform the way I want it too?"
In this case, yes. I only live a couple miles outside town, and the next town is ten miles away. I can use this cycle to drive all over locally, and head to the next town over and back on one charge.

In real-world driving tests, the single-charge range of the cycle came to 23 miles if I drove full-tilt, and 32 if I was doing easy acceleration and in the city 25 mph zones.

Lead batteries are NOT light. It helps to make a mock-up from foam or cardboard, so that you have a LIGHTWEIGHT, easy-to-handle version of the battery to experiment with. I like to think of this as the poor-man's C.A.D.

If you are into computer design, there are many great programs out there to help you create 3D images and think in three-dimensional space. Google Sketchup seems to be getting fairly popular. Still, you really can't beat an actual, physical object in your hands. I just prefer something that weighs less than lead.

In my earliest version of the cycle, I had three batteries in it. Then I moved up to four (for more range and higher top-speed.) I was never sure how to fit four inside the frame in a way that fit well and looked good. By using cardboard mock-ups, I was able to experiment with various arrangements of batteries until I found one that I liked. In this case, the fact that I could mount these batteries turned on end allowed me to come up with a configuration that I liked.

Once the size and number of batteries are decided on, they need to be physically mounted inside the motorcycle, and solidly connected to the frame.

Edit: Please note - Battery technology has been changing rapidly the last few years, largely in thanks to commercially-built electric cars. Lithium cell modules are SIGNIFICANTLY less expensive than when I built the Electric Kawasaki. At this point, if I were building an electric motorcycle, I would go directly to lithium cells. Please keep in mind that with Lithium, you need some sort of BMS (Battery Monitoring or Battery Management System,) and it needs to be charged appropriately. Please visit a web forum for the latest availability and best practices with Lithium Batteries.

<p>Ben your instructable was a huge help to me in figuring out my own electric motorcycle conversion project, so thanks for sharing! I thought you might be interested to see the instructable I just posted for my project: <a href="https://www.instructables.com/id/Engineer-Your-Own-Electric-Motorcycle/" rel="nofollow">https://www.instructables.com/id/Engineer-Your-Own-...</a></p>
<p>I've finished an EV bike of my own, however, I cannot find a drive sprocket and no guide talks about what sprocket they used. I am running an eTek motor with a 7/8&quot; output shaft and a 3/16&quot; keyway on a 520 chain, likely a common setup... what sprocket did you use? Where did you get it? My project is sitting in the garage until I find one :(</p>
Which will give more efficiency.. Series connection or parallel connection?
<p>It's not really that one or the other - series or parallel - connections are more efficient than each other. In series connections, voltage increases. In parallel connections, current or capacity increases. However, with DC motors, speed is proportional to voltage. Therefore, connecting your batteries in series is the preferred way to go. You get a higher voltage, thus higher top speed from your motor. Also, higher voltage means lower current draw for the same amount of power. Lower current means that you can use thinner cabling, which is less expensive, easier to work with, and saves weight.</p>
I'm living in an hilly area. So will a 36 volt help me.. And will it charge my battery when going down hill.. <br>
<p>The motor wont natively charge as you ride down hill. In some cases you can use a second motor to charge batteries, but it's easier to do with an alternator of some sort. Either way, though, you need a way for the whole unit to only engage when you when you are going downhill; if you don't you'll be using your drive output from the batteries to turn it. 36v may work for you, but it may not. with a hilly area you want something that is going to put out a reasonably high amount of torque (you can play with this a little bit with the ratio of your drive sprocket to wheel sprocket). Some motors (like those used in off-road winches) are super high torque, and don't spin very fast, but they only require 12v to go. Others are relatively low torque, but relatively high horsepower (which directly affects top speed) and can be 24v-72v or more. With one from a winch you could, in theory, use a gigantic drive sprocket and a tiny wheel sprocket to compensate for the slow speed of the motor. It depends on how in depth you really want to get with this build. I recommend researching the physics involved and figuring out what requirements you will need to deal with your hills and then comparing with the specs of different motors on the market.</p>
Thank you somuch mr.bennelson for your keen support for youngsters, who try to live without pollute our environment.
<p>Wow this is one of the best electric bike tutorials I've found! Thanks for putting so much detail, definitly helps a lot!</p>
<p>Looks amazing . I am trying to learn more about diagnosing issues I am having with my electric DIY cargo bike build. Should the three phase wires running from the controller to the hub carry full voltage under WOT? I am running a 48V system with a brushless direct drive rear BMC hub. Reading 54V under a full charge 15 ah battery. Reading 11.88 V at each phase wire, not changing under throttle movement. </p><p>Appreciate it !! </p>
<p>Great Build and info! I have a DIY cargo bicycle that I am trying to diagnose a failure on. If I run a 48 V system producing 54 V under a full charge should I see that on the three phase wires coming from the controller running to the brush-less direct drive rear hub as you twist the throttle? Appreciate your time ! </p><p>Donny </p>
<p>Where I live (NL) scratchbuilding anything to drive is illegal, unless you have a company that specialises in it, plus you need to give the government at least 3 models for crashtesting and safetytesting and you will have to pay for getting them recycled and/or scrapped and transport and for the testing itself, plus however many more they require but never more than 12. Motorcycle tests are fewer so maybe you can get away with only 2 or so but they will be wrecked. They will run them into crastest dummies to test pedestrianfriendlynes in case of accident and rate it accordingly. So if your homebuilt cycle fails you are done for. </p><p>Putting batteries on something also will open you up for testing for leaks and accidents, so likely crashtest to test what happens with the battery if it hits a truck.</p>
<p>is there a way for batteries of higher voltage to be used on a motor of lesser voltage where the motor will only take its recommend amount. This question is based on long distance travel where highway and city driving are necessary,</p>
<p>This is my first time on this post. I read a lot of the posts and a lot of interesting info. I have built a couple of Electric KTM dirt bikes, and am now building a Yamaha Steeel frame electric with a gearbox. A lot of the questions that every posted are good, and I have worked thru most of them. My KTM is a 2008 250SX-Fframs and running gear, a Motoenergy ME1004 48V 200-400A motor. I have been using the Kelly controller. I bought over what I needed 72V 500AMP with Regen. I am using a Magura 5k throttle and it works fine. My batteries are CALB 40AH x 16 cells to give me 48V 40AH ( about a 2KW battery pack)</p><p>I get 6 hot laps on the motocross track or 15 miles on the street, I was able to make it street legal in California since it was converted to electric. I did not modify the frame so I could put the motor back on, but I love the electric aspect of the bike.</p><p>It is on EV Albums &quot; 2008 KTM Electric&quot; under Motorcycles</p><p>To answer a few questions , the Kelly controller has been very reliable, and the Regen Braking turns the motor into a Generator, which works great on this bike. At a motocross track you rely on engine braking, with electric you don't have any, regen braking is the answer and you can program in as much in as you want, or you can vary it with a rheostat</p><p>The bike has been very reliable , and a lot of fun . It is neat have and play with it. It is encouraging to see all the people on here interested in electric build of there own</p><p>Dcoxryton</p>
Would it work if I put it all in a mini moto ??
<p>I just recently saw a Trail Buddy converted to electric. It was really cute, and an all the electric components were really well packaged. I didn't see it on their home page, but it was built by these guys. http://www.trail-buddy.com/home.html</p>
<p>You can pretty much build any size electric motorcycle you want, However:<br>1) If you build it really big, you will need a very powerful motor and high capacity battery pack.<br>2) If it's a very SMALL motorcycle, you will have very limited room in the frame for all the components, and will only be able to fit smaller batteries.</p><p>A mini motorcycle sounds like a lot of fun. You could probably get away with using the style of lithium batteries used by high-end RC Car enthusiasts.</p>
<p>I recently obtained an old 1950s Harley Davidson frame from a friends junkyard. It does not have a VIN# because this was from a time before they put VIN#'s on frames. The odd thing about it, is the DRF XXXXX number on it. Does this mean it was stolen? Will I ever be able to register this old of a motorcycle frame before I start building on it?<br><br>Thanks for any help.</p>
<p>Depending on your state laws you will probably be able build it as a new custom. My suggestion is to sell that frame to a collector and buy a complete bike with a blown motor. Old Harley frames are heavy and parts are expensive. </p>
I think the last sentence you said kind of sealed the deal for me.<br>Looks like I'll need to find a Collector! <br><br>Thanks again<br>-TM
<p>I've built a 72 volt version from a Suzuki 600 Katana. weights about 500 pounds.</p><p>This was built in about 1 week give or take a few days. the current picture is Version 3. the first version was a 48 volt 75 Ah system. Version 2 was 72 Volt 75 Ah version, but the final version was 72 volt 101 Ah version. current version gets between 30-40 miles per charge depending on driving conditions. only an estimate since it is only 22 miles to work @ 50 mph and i recharge it everyday at work, so i never really never had a chance to kill the batteries that much.</p><p>This version has a dual laptop battery pack for the light and a 72 volt battery pack for the Drive motor. all lights are custom built L.E.D. lighting that i made my self from 12 5050 L.E.D. strips.</p><p>This version uses about 50- to 65 amps at 50 mph.</p>
<p>I like your electric scooter selling service..<br>http://www.billelectricscooter.com/</p>
<p>great</p>
<p>First of all, thank you for putting so much time into such an awesome instructable! This is really helpful. Secondly, I have a question. I'm looking at doing this for a 2001 Yamaha R1. It's perfect as the engine is in good nick and the transmission is busted, but I'm wondering if it's too heavy for the electric motor you used. I'm new to EL motors and trying to make a go of it with this project. What do you think? Could it work? </p><p>Cheers!</p>
Hi!<br>Put in few words, with same motor and more amps-hour (more energy stored), go farther.<br>Readequate motor (to get more power - more watts), more amps-hour, more speed depending on gearing. Same range. It's not so simple, you have to equate all variables for your goal.<br>Usually motors with higher voltage can develop more power.<br>Of course the correct is that you have a target power, say 750W (~1 HP), for sake of simplicity: 75V x 10A to feed the beast. Or, 32,5V x 20A. Or 150V x 5A. And it goes on. Higher voltage also allows thinner wiring (to hold less current)if you manage to have a motor that runs this figures at 12V, you would need to provide 62.5 Amps. Imagine the wiring for this now. Research motors, batteries, weight, your goals and spreadsheet it to find your personal solutions having in mind what you want. :)
<p>Wow what A dream bike..<br>I want to build my own like yours. <br>does it become a 96v18ah battery if i connect two 48v9ah batteries?<br>This is what I found on alibaba website </p><p><a href="http://www.ebike-bmsbattery.com.cn/product/690588130-215068276/e_bike_48v_lithium_ion_battery_ups_battery_48v_lithium_ion_battery.html" rel="nofollow">http://www.ebike-bmsbattery.com.cn/product/690588130-215068276/e_bike_48v_lithium_ion_battery_ups_battery_48v_lithium_ion_battery.html</a><br>Lifepo4 48v9ah E Bike Battery,e-bike battery,ebike battery<br>Item No. Voltage Capacity battery type Lifespan <br>BMS<br>Option<br>Charger<br>Option<br>Dimensions Weight<br>G-BP4809A 48v 9ah lifepo4 <br>&gt;2000<br>cycles<br>15Amps 3Amps 69*148*360mm 4.9kgs<br> <br>48v 9ah electric bike li ion battery Characteristics<br>a. Very Security: No fire,no explosion,no leakage ;<br>b. Portable handle and hidden charging port;<br>c. Aluminium alloy Back rack(Silver and Black for option);<br>d. Well die-casting slide board and lock, for easy installation and theft-prevention.<br>c. 30A Fuse and smart BMS are included for protection<br> <br>Pictures and detaild data sheet</p><p>Model G-BP4809A<br>Norminal voltage 48V<br>Rated capacity 9Ah @0.5 C3A, 20&deg;C<br>Operating current 15Amps(can be customized) <br>Peak current 30Amps(can be customized) <br>Charge voltage 58.4V <br>Standard charge current 3Amps <br>Cycle life &gt;2000times <br>Dimensions 69*148*360mm<br>Weight 4.9kg<br>Battery box material aluminium alloy <br>Built in battery cells 3.2V 9AH polymer lifepo4 cells <br>Assembly 16 cells in series<br>Operating temperature - 20 &deg;C to 60 &deg;C<br>Charge temperature 0 &deg;C to 45 &deg;C</p><p>it weights about 12 pounds.<br>What do you think? No one can answer my question.</p>
<p>Hi.</p><p>Batteries Voltage adds up when in series, but current does not. If you put 2 batteries in parallel, you will get same voltage but will add the current. This is very very basic electricity.</p><p>To achieve your 96/18 figures you need 4 batteries, putting 2 pairs of 48/9 parallel batteries in series. I mean take a pair and mount in parallel - call it now pack 'A'. You now have a 48/18 pack. Then take 2 of this packs 'A' and put in series then you have your 96/18.</p><p>Best regards</p><p>Lissandro</p>
Thanks. Sorry for bothering you but if you dont mind i ould like to ask you one more question. Would my bike run faster and run farther if only current(AMPS) goes up? I think there is extra space for a pair. in that case a pair becomes 48v/18ah?
<p>No, current has nothing to do with range or speed. On a DC system, speed is determined by voltage and gearing. RANGE is primarily through battery CAPACITY, which is measured in AH - amp-hours. Being able to draw more current can get you to your top speed quicker (better acceleration) but won't change the top speed.</p><p>If you add additional batteries in parallel, this will increase the capacity of the pack, and give you better range. Current is only related to range in that batteries will give you less total range at high current than low current. Also, if batteries are the limiting factor in how much current you can draw, adding more in parallel will allow you to draw more current. </p><p>Remember that current (measured in amps/ampres/A) is flow, it is a RATE of power use. Amp-Hours (AH) is a measure of capacity. </p>
<p>Questions:</p><p> 1. Why a drive between the motor and the wheel? Why not have the motor in the wheel hub? Wouldn't this be more efficient?</p><p>2. Do you still use a gearbox? If so, why? Cant you use direct acceleration?</p><p>3. Why have a braking system, once the vehicle is stationary, wont it only move if you apply power?</p><p>4. Could you use this same system to make an electric cruiser?</p><p>5. Where can i get an high efficient high speed motor?</p>
<p>Hi Alexander!</p><p>Answers:<br>1: Chaining the motor to the back wheel allows for both adjustable gearing (by changing the sprockets) and for placing the motor where I would like it. Hub motors of the right power ARE now available for motorcycles, but have not always been the best thing for high top speed. Direct drive also doesn't usually give you the same &quot;oooomf!&quot; that you can get with a chain drive. Also, a hub motor increases &quot;unsprung&quot; weight, which isn't as good for handling. My project as of spring 2015 is a Vectrix, which DOES use a rear hub motor, but it also has planetary gearing to overcome some of the limitations of hub motors.<br>(http://300mpg.org/2015/03/02/vectrix-maiden-voyage/)</p><p>2: Please see step 11. <a href="https://www.instructables.com/id/Build-Your-Own-ELECTRIC-MOTORCYCLE/step11/Driveline-Sprockets-and-Gear-Ratios/" rel="nofollow">https://www.instructables.com/id/Build-Your-Own-ELE...</a> It clearly shows that there is no transmission. The motor is chained to the rear sprocket. Yes, it is more efficient than with a transmission, there's fewer moving parts, it also saves space!</p><p>3: Brakes! Yes, of course I have brakes! The cycle came with brakes, I did not change them. Why would I want to remove the brakes! Yes, once at a stop, the cycle doesn't move, unless on a hill. Brakes are most important when you are moving and want to slow down! The vehicle doesn't have &quot;regenerative braking&quot; or any special system other than the stock regular motorcycle brakes.</p><p>4: Yes, you could build an electric motorcycle similar to the say I did, but build it as a standard, a cruiser, a sport bike, a scooter, or whatever style of motorcycle you like. Sport bikes are popular for conversions because of their light-weight aluminum frames.</p><p>5: There are many mail order companies on the web that sell electric vehicle parts. Just do a web search for them. The Electric Auto Association also has some nice links on their web page. <a href="http://www.electricauto.org/?page=EVsForSale" rel="nofollow">http://www.electricauto.org/?page=EVsForSale </a> Scroll about half way down on that page to &quot;EV Converters, repairs, &amp; kit or component suppliers&quot;, you can order parts, including motors from those places.</p>
<p>Dear Ben,</p><p>I have a 1972 honda dirt/trail bike whose engine seems to me not worth restoring, and I have toiling with the idea to convert to electric for the longest time, refreshing my parts wishlist from time to time.</p><p>At last I've seen the Enertrac 18&quot; hubmotor, and its the ideal motor in my opionion. However, as with any electric application, battery technology seems to let us down in various combinations of cost, weight, size, and amperage (cost in particular). </p><p>I have seen your batteries on your Kawa and its damn huge (and heavy). I am thinking of using LiPO batteries from hobbyking (those used in large scale electric RC) - just need your two cents on this opion.</p><p>Tks,</p><p>Aszman.</p>
Hi ErfanA1,<br><br>Yes, you are right, lead-acid batteries ARE heavy. In fact, right now, I'm upgrading my Kawasaki to NiMH batteries I got out of an old Ford Escape Hybrid! (Nickel is still heavy, but it's better, and the salvage yard price was GREAT!)<br><br>Hub motors are becoming practical for EV motorcycles, and have already been used on many EV Scooters.<br><br>Lithium batteries are great. You might want to see about going on the Endless Sphere web forum. Those guys are into electric bicycles, but have GREAT knowledge to share about using small lithium batteries.<br><br>Good Luck!
<p>SUH-WEEEET-AH!!! </p><p>So 'ok...you've got the info I needed and explained clearly...more clearly /less cluttered than most other related instructables! Now can you answer me this...the wires coming from the controller to the throttle.....could an arduino replace the throttle? this would be for remote or programmed motor &quot;control&quot; ie: instead of a human hand turning a physical throttle...an arduino sending signals to the controller as though it (arduino) IS the throttle...? make sense?...others have jumped all over me for this...but I think the 2 wires can act as the potentiometer..? yeah?</p>
On my motorcycle setup, the throttle is a 0-5Kohm twist potentiometer. To replace this style throttle with an Arduino, you would need the Arduino to be able to create a variable resistance in that range. I haven't played around with Arduinos very much at all and would have no idea how to do that, but I'm sure somebody could figure it out.<br><br>There are also motor controllers that use a variable voltage of 0-5 volts as their input. Voltage can be varied by PWM, and I know that can be done by Arduinos. So, it may be an easier approach to use a controller with that style input.<br><br>Due to safety considerations, I would NOT create any kind of &quot;experimental&quot; throttle for an on-road vehicle, but if it is for some sort of stationary machinery, just follow typical safety precautions and have fun!
<p>YES!! thats the numbers I was lookin' for!!! I'm just starting arduino as well but, if I'm not mistaken 5v is exactly what the arduino needs /handles.</p><p>I'm sure a resistor or two would make it a little safer I think? arduino pros?</p><p>the applications of this could be for giant remote control cars, a stationary sculpture...anything an arduino could influence via...PIR sensors..bluetooth phone remote control...timers etc.</p><p>Much Thanks Bennelson!!</p>
<p>I have lots of bikes but I have this 74 cb 360,I took this cbr 600 that I had ,it was from a police chase and it was never picked up from the cops after its rider got away after it slide own on a golf course so I got it after it sat at the tow company for a couple of years..never could get a title for it so I sold its engine and took off its rear swing arm and front forks which bolt directly ODDLY to the 74 cb..I welded on the rear swing arm to make this cafe bike....but Id like to convert it to electric since I have 3 more bikes including the 75 cb 550....which will be cafe also but still a gas burner..I want an electric motor that goes faster than 45 mph..any suggestions?Im going to run lithium batteries Im thinking.</p>
For high speed/performance, it's best to go with the highest voltage motor you can. 72V is pretty popular for a fun lithium bike. Motenergy has some good motors. Check them out.<br>http://www.motenergy.com/
Can you use the existing transmission system of the bike??
On most motorcycles, the engine and transmission are really a single, integrated unit. It's very difficult to remove the engine, but keep the transmission. You CAN build an electric motorcycle with a transmission, but the tranny takes up space that might better be used by having more batteries. <br> <br>What a transmission in general really does is convert engine speed into torque. Electric motors tend to have HIGH torque at LOW speeds, so you don't neccessarily need a transmission. <br> <br>For a commercially-built EV cycle WITH a transmission, take a look at the Brammo Empulse.
<p>How about getting hold of an old pre-unit Triumph (or other manufacturer) gearbox? They are small and lightweight and also very strong mechanically. You should also be able to get different gear cluster set ups at a reasonable price.</p>
But couldn't you gear that high torque down to get better top speed/further range?
For higher top speed, you would use high gearing, which would pull greater amps. Pulling higher amps creates more heat, shortens battery life, and reduces how far you can go per charge.<br><br>In general, to increase top speed, you are best off increasing your system voltage.
<p>Good day Sir, i would like to ask if this bike could be build in South Africa too, and if i may request the plans for this bike please. Would you consider to open a factory here in the RSA ? A lot of jobs can be created by this and you may profit a lot by it too. My email is just1info@gmail.com 073 327 9390 thank you very much.</p>
<p>Good day Sir, i would like to ask if this bike could be build in South Africa too, and if i may request the plans for this bike please. Would you consider to open a factory here in the RSA ? A lot of jobs can be created by this and you may profit a lot by it too. My email is just1info@gmail.com 073 327 9390 thank you very much.</p>
<p>Good day Sir, i would like to ask if this bike could be build in South Africa too, and if i may request the plans for this bike please. Would you consider to open a factory here in the RSA ? A lot of jobs can be created by this and you may profit a lot by it too. My email is just1info@gmail.com 073 327 9390 thank you very much.</p>