Introduction: Turning a Dead Scooter Into a Speed Machine!

The goal of this ible is to show you how to fix the most common problem with small electric scooters. The most common issue is related to the battery, followed by the charger, meaning these are often available for anywhere from 50$ to free.

What is more, in fixing this, we can easily make it 50% more powerful with stock hardware (changing nothing else) and 100% more powerful with a full rebuild. I do not have the parts for a rebuild yet, so for now this will focus on the easier and simpler upgrade modification.

As always, questions and feedback are welcome. If you like what I do, please follow me here and subscribe on my YouTube channel. Thanks!

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*extra note* I designed this as a 2 batteries in series; I would recommend doubling that to 2 in parallel x 2 in series for longer rides. The 15 amps drawn continuously for approximately 10 minutes made the plastic around my battery terminals go soft and they shifted. However, I don't consider this to be dangerous per say, the battery was in good shape chemically, it's just the plastic that was not doing so well at this point.

Step 1: Material

Picture of Material

The standard equipment needed will be

  1. Your scavenged scooter, or new for as little as 170$ (see below)
  2. Batteries and appropriate connector and charger (see below)
  3. Anderson Connectors
  4. 12 gauge wire (14 if you must, but try not to skimp, you will lose power).
  5. Wire strippers / snips / pliers
  6. Screw drivers (probably number 2 Phillips, but look at what your scooter has)
  7. Replacement nuts and bolts if yours are all rusted as mine were
  8. A soldering torch
  9. A helmet

First and foremost, you will need an electric scooter. There are three "main" popular models (and them some derivatives of those). The Razor E100, E200, and E300. There is also a less popular E90. All but the E90 are modded the exact same way. If you happen to have an E90 (the less common of the bunch), keep the voltage to half of everything specified here (so a single 18v battery instead of 2 in series).

The second major thing that can vary quite a bit is your power source. You can replace it with more cheap-ish lead acid batteries (not much of an upgrade as you will still be using a 24v system with the same issues as the original). The next option is using lithium batteries, and this is where it can get a little tricky. There are many options, and you can build a pack from scratch, but that can be an large undertaking, requiring quite a bit of learning. The easiest lithium option is to buy a ready-made pack (can be hard to pick the right one, lots of confusing options), or make your own from safe and reliable power tool batteries as I show in my other ible https://www.instructables.com/id/Using-Ryobi-Power...l

I will actually be using a custom pack long term, but for the ible I will stick with the Ryobi pack, as it is much easier to test with such a flexible option.

Step 2: Back to School: Why Does This Mod Even Work?

Picture of Back to School: Why Does This Mod Even Work?

When building electric vehicles (or working with motors in general), there are three related ratings. Watts is the total amount of power (either as torque or speed). Voltage determines the speed, and amps the amount of force with which the motor turns (torque).

  • Total power, or Watts (W) = voltage x amps.
  • Each motor and motor controller is capable of a certain amount of total power (W).
  • Each motor is capable of a certain amount of amps (theoretically voltage too, but inconsequentially in this case).
  • Each controller is capable of a certain amount of volts, and controls the amount of current (amps) that flows to the motor.

Now it so happens that the way in which controllers a built accounts for a bit of extra headroom. So a 24v controller can usually handle a 36v lithium battery. The issue that can come from this is the low voltage cutoff would be set too low. This is where having a battery with a built-in BMS (battery monitoring system) is important, and guess what! Our Powertool batteries have that!

This means that our 36V scooter won't be able to pull anything heavier than it did before (no change in amps), but if it was able to reach top speed before, now it should go 1.5x faster!

Step 3: Removing the Old Battery

Picture of Removing the Old Battery

The first step is to remove the battery. To do this, you need to remove the base plate, which is held in by a few nuts and bolts. Once this is done, you can simply snip the battery out. Only cut one wire at a time, and make sure the freshly cut wires don't touch your snips while you cut the next one, or you may just weld them in place if there was enough of a charge left (or at least make a few sparks).

If you are using a custom pack and the appropriate charger, you may also want to remove the old plug as it is a harder to use style and we are moving on to all Anderson connectors. Do make sure you label everything as you are cutting it.

If you are using power tool batteries, the batteries will likely not fit in the base (and would be a pain to take in and out), so you will most likely have them in a bag or a caddy of some sort, which means you need to run wires to power everything down there. You can either make a new hole for running your power cables, or you can remove the old charging connector and re-use the slot to feed your battery power in there.

Step 4: Get Our Wiring Ready

Picture of Get Our Wiring Ready

We now need to add Anderson connectors where the batteries used to be plugged in. I am choosing to have a very short run with Anderson powerpoles staying down in the base, and my batteries will have a very long cable running down to the "inlet".

The wiring can best be seen in the video instead of a bunch of pictures, but essentially, the link between the batteries and the fuse have to be changed. The picture does have notes to help you through the steps.

The red wire from the battery is still going to go directly to the new battery. The black wire from the controller is going to be re-routed to the fuse, and from the fuse, we go back to the battery. In my case, the easiest way to re-route through the fuse was to have the fuse wire and "-" (black) wire that goes into the controller directly soldered together. This left me with 2 lose wires that I had cut that now needed to be re-finished with the anderson connectors.

For safety reasons, I am also adding Anderson powerpoles near the battery, so the cord between the battery and the base will just act as a quick release extension. This way, if the cable ever gets snagged, there is less risk of damage.

For more on how to do the wiring, you can see my two ibles for more details, or go with your own battery option.

This first one on how to make the harness.

This second one how to crimp anderson connectors.

Step 5: Close It Back Up and Enjoy

Picture of Close It Back Up and Enjoy

That's it! Close it back up, connect that 36v battery pack we built in my other ible, strap on your helmet, and enjoy!

Comments

johndeere754 (author)2017-04-05

How much difference would it make if I'd use 3ah ryobi batteries rather

then 4 ah like you used.

25%?

I guess it would run for a shorter amount of time, not have less power?

Also, we talked about going with 4 batteries instead of two.

Does it matter if two batteries would be 3 ah and two 4 ah ?

Or even if you had only two batteries. Would it matter if one were 3 ah

and one 4 ah? Or just less ah?

The reason I am asking is because the lower ah batteries are less expensive. These batteries can be very expensive!

MakinThings (author)johndeere7542017-04-07

Something I had not thought about if running these at 18v. If it was a 12v, it will likely be pushing it but work (like I did with 24 to 36), but on a 24v controller, you may be below the safety shutoff and the scooter simply won't accept the pack. I think the normal cutoff for this would be around 20v... so 18v won't work.

MakinThings (author)johndeere7542017-04-07

Well the harder you push batteries, the less you will get out of them. So with 2x 3Ah packs in parallel, you would get a bit more run time than if you took each battery 1 at a time. The same is true from 3 to 4.

You do not want to mix 4 and 3 ah batteries, but rather make 2 packs. The reason is that the smaller one will drop voltages sooner, so if the average voltage stays too high overall, you could over-discharge your 3ah batteries and prematurely kill them. If you do go with 3ah and 4ah, you would have to find a way to stop when the 3ah is discharged. They are expensive I agree, which is why some NiCads might be nice for this, especially since you can find people getting rid of them for free if you take your time. The 2x 3ah would give you something like 15-20 minutes run time, which is respectable. If the 3Ah are much cheaper, then they will probably be better value. At 6ah pack, running the cells at 15 amps (what the controller should top out at), will be reasonable for this kind of battery. If it were a laptop battery, it would destroy it, but power tools can easily draw 10+ amps continuously (with higher spikes) on a single pack. Doesn't mean it's not going to add some wear, but any pack being used at high currents will take extra wear.

If you do 2x 4ah and 2x3ah, you should get to know what the safe operating voltages are and install volmeters for each pack. This ads cost and complexity obviously, so it kind of defeats the purpose of this. At that point, you should start learning all the basics and build a pack.

But again, if you are using the newer pack, they do auto-shut off and using them in parallel could be tricky. The way to know if it does this is to test the voltage with a voltmeter (not the battery tester button). If it says something like 5-6 volts, then it is in the standby mode, and you will likely have trouble with it.

johndeere754 (author)2017-03-31

HI Mr "Makin Things"

I have an E225 Razor and want to do the same thing.

I assume you used 2 18v 4 aMP batteries?

Does one HAVE to use the charger attached to the batteries? (the things with the lights on them)

And you even suggest using 4 batteries? 2 and 2? wouldn't that burn something out?

Or did I misread that?

Anyway....can't one just connect the battery terminals together somehow instead of using the chargers? Just wondering.

Did you get more speed and power?

My Razor being a 24Volt, as I think yours is..... the 36 Volts put out by the batteries was no big deal?

Thank You for your help and insight!

I don't know where else to contact you?

Jonathon

jpsiemens@hotmail.com

MakinThings (author)johndeere7542017-04-01

Alright, quite a few questions there.

There are a few things here. First the 24v controllers are generally rated to 36 volts, but there is no guarantee. In the case of the Razors, when I did find the parts and look up the specs, the 24v did seem to be able to take it. Now, HOWEVER, they do this to have some over head in case parts aren't perfect or whatnot. We are effectively removing that overhead when running at 36 (upwards to 40v when fully charged because of the float charge). MORE IMPORTANT STUFF ON THIS BELOW.

Next, yes it has to go through the controller, for a few reasons. One of these reasons is that it controls and limits the current going through the motor, which is important as we will see next.

For the batteries, when you say 2x2, I assume you mean 2 series 2 parallel. Series = more voltage, parallel = more current. BECAUSE the controller limits the current, when it is in parallel, you simply have more runtime AND put less stress on your batteries. This is not universally true, but in this case it is because of the controller, some other devices would just draw more current, overheat, and burn up. That being said, batteries auto-shut off, and I had issues with running them in parallel, older-style Ni-Cad batteries may be better for this.

For the series part, it increases voltage. Now what happens is the controller does not limit voltage, so although we don't increase the current going through (which would almost certainly melt things), we are still increasing the total power going through (W=V*A or watts = voltage x amps). This means that some parts are still going to be pushed; the motor for example, would be running at 1.5 times its usual wattage. This will still cause some parts to heat up, and so extended use could cause issues. Case and point, may failure point was my batteries. The terminals got hot, and the plastic of which the batteries are made were not rated for that kind of output. The plastic deformed. Do I care? no. Will you? possibly. If you are worried about longevity/want to use this a lot, you might be better off using only batteries in parallel. Take the hit to speed, but you would be running under spec, so longevity is good, you get the interchangeable packs, the quick charging, and much longer range. Also, although you technically don't get more power, since the batteries are better at taking this than the lead acid batteires, you get a more consistent throughput, so you don't lose as much power when you run it longer because there will be less voltage sag and so a more consistent ride (assuming your battery was sufficiently large in parallel, 8Ah in parallel = good, 16Ah = very easy on the batteries). Feel free to ask more questions, I usually respond within a day or two. By putting it here, we get to share it with anyone else with these questions :) Also, if you want to help me out, subscribe to my ible and youtube!

sshipley4 (author)2016-06-22

I have a couple computer backup power supply units, each having 3 individual batteries themselves. could I use these as a replacement possibly

MakinThings (author)sshipley42016-11-05

Yes and no. First off, it is important to note that mixing batteries that are not identical is not recommended. If you charge them separately, you could make it work, but it would require active monitoring of the batteries and a good understanding of what you are doing. Luckily, the most you could do is damage them, not start a fire as is the case with lithium, but still.. no one wants to damage their batteries. If they were produced at the same time, have similar wear, and are same brand, then you should be good to go, but then you have more things to consider. How you use them would depend on the ratings. Parallel = more power (necessary to accelerate and / or keep the speed up), voltage = more speed. If they are 12V, 3 in series would give you 36v at whatever amp rating it is capable of. If they are 6v, then you will only reach 18V, which will just continuously trip the low voltage protection circuit. Some (rarer) batteries are 24V. Normally companies just slap 2 12v together, but still.. If you do have that, putting 2 in series would burn out the mosfets, so you would have to use them in parallel.

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