Converting An Old ATV To Electric Drive

[RCLifeOn] happened upon an old petrol-powered ATV that had seen better days. He decided it was the perfect candidate for a conversion to electric drive.

First up, the chassis was stripped back and cleaned, before being given a fresh coat of paint. It then got fresh valve stems for the tires and was ready for its drivetrain conversion.

The motor of choice is a brushless type, rated for 42 kW at 120 V. [RCLifeOn] doesn’t have batteries capable of maxing out those specs, yet, but carried on with the build. The motor was mounted on the chassis, and a 3D printed hub was installed to get the sprocket on the end of the motor.

A stress test uphill killed the speed controller. This was not unexpected, as it was a cheap unit severely undersized for the application.

The first drive was rough and ready, as the speed controller wasn’t sensored, the gearing wasn’t quite right, and the chain wasn’t very tight. However, it did successfully make it around the grass, slowly. Further improvements then included a water cooling circuit for the speed controller and the addition of a battery compartment. That wasn’t enough to stop the speed controller bursting into flames during a difficult uphill climb, though.

Fundamentally, though, the project shows promise. Bigger batteries, a sensored speed controller, and appropriate gearing should make it a quick beast. 42 kW of power is a good amount for a light ATV, plus there’s the benefit of instant-on torque from an electric motor.

We’ve seen [RCLifeOn] tackle some high-powered electric builds before, like his impressive powered surfboard.  With the right parts, we’re sure he’ll have this thing ripping about at pace before long!

13 thoughts on “Converting An Old ATV To Electric Drive

  1. It is a bit baffling that this guy isn’t using incredibly popular, significantly cheaper mid-drive e-bike motors which already have reduction gearboxes in them and are designed for roughly the speed and torque he needs, come with ESCs that won’t burn out like this, and have chain cogs on ’em already. It wouldn’t be as fast as a gas ATV in terms of top speed, but it would be plenty strong off the line to have some fun.

    You can walk out the door for well under $1k with a motor, ESC, display units, control, battery, etc. Build a mounting bracket ideally with an eccentric adjustment, source a heavy-duty single-speed chain, and you’re largely done.

    One thing of note: ATVs are insanely dangerous. One would have to give careful consideration to how the electric conversion has altered the Cg and so on if one plans to ride it beyond tooling around in the back yard at 10-15mph.

    1. I think you might be unfamiliar with RCLifeOn. He primarily deals with ‘RC’ grade components, and typically designs things himself with what he already has on hand.

      Sure, you could buy a kit with properly sized and ready to go components – but where’s the fun in that?

    1. You should do that. A 1500w mid-drive electric bicycle motor will run about $1k, then add a sufficient battery for $600. Can switch the battery between bicycles and 3-wheeler to avoid redundancy. All kinds of non-running ATVs on craigslist.

    2. I’m about to start a build with a predator 90 quad My goal is to turn it into a quad scooter or mobility scooter that I can use As an off-road platform and convert over to electric power But I’m not quite sure how to do it If I should buy the kit with the rear end intact Or go with breakfast motors or hub motors any suggestions where to start would be helpful

    1. In my experience, a 42kW motor like this will only produce about 7kW unless you have a motor controller and battery each roughly the size of a bread box. If you’re discharging a high C rating 30Wh RC batteries in less than 15 minutes, no worries, just a fewer cycles. When you start discharging larger 10,000Wh batteries in less than an hour, you need massive cell cooling. Not just for safety or reliability or anything like that. That’s just so you can get the power out.

    2. At 48v, you would need 875 amps to get 42kw. 120v would need 350 amps. Being insanely generous estimating that setup without full details I’m guessing it was maybe seeing 4-5kw.

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