EzGo Gas to Electric Conversion

[journeyman846]

Hey guys! New to the forum here. I picked up two EzGo carts with no engines for pretty cheap. I have converted quite a few things to electric so I decided to go that route with these. I have installed a 22s3p A123 LifePo4 pack paired with a Motenergy 1306 motor. I have everything installed and finally got it out on the road for a test drive. The two problems I have now is that this thing is sloooooow and the chain noise is extremely loud. I have to assume the slowness is due to the gear ratio of the transaxle being so high. I also assume the chain noise is because I decided to go with the larger 520 chain. I know this motor is more than capable of pushing this cart as I have an electric go-kart with the same setup that will pop wheelies and tops out around 60mphs. Any thoughts on what I can do to improve speed? I am thinking about swapping the axle for a solid live axle but am not sure if there's any other route. Suggestions? The current sprocket setup is 12t on the motor and 14t on the axle.

[Cartmaster]

Welcome to the forum.

As You almost have a 1:1 ratio on your chain gearing, The issue can only be with the motor RPM compared to the internal gearing on the trans axle as far as i can see. These carts are slow anyway, probably around 15 MPH stock. If you are looking for more speed, then a direct drive to a live axle will be your best bet, but you will lose the reverse facility from the axle and will need to run the motor in the opposite rotation to achieve reverse. Not so difficult to do with a reversing contactor available from site sponsors. I assume you have matched the voltages on the battery and motor?

another way to achieve what you want would possibly be to run a CVT clutch system from the motor similar to the stock gas setup. You will then have the reverse facility in the axle in use and can run the motor in a single direction but you will not really gain any speed with this. I assume you are using a solid state controller for the motor, so maybe reverse is not an issue and a live axle is the way to go.
I am in no way an expert on electric carts and maybe someone else has a better idea.

Chain noise is something you will have to put up with i think, but maybe incorporating belt drive instead would solve that?

[crash12888]

A cog belt and sprockets drive similar to motorcycle applications will be a lot quieter and will not rob you of power due to the V-belt friction characteristics.
Your theories and build look good.

Maybe swap in an electric axle and direct coupler system?

[Cartmaster]

Crash, I think the only way we are going to get any speed out of that is to go with a live axle direct drive with either chain or belts and work out the best gearing ratio with sprockets to use. Depending on the RPM's the motor can run at, the axle gearing will be the deciding factor on speed. I get the impression we are looking for real speed, not golf cart speed LOL. I dont know electric cart details, but I doubt the gearing is much different to a gas axle, therefore not really a speed option. If the Motor can spin faster then maybe we can look at high speed gear set and taller tires, depending on the spec of the Motor, torque may be an issue with very tall gearing. It may be worth trying changing the chain gears to have a smaller one on the axle and bigger on the motor but again, can the motor cope with that.

EDIT.

Actually, looking closer, going back to chain noise, It may be harsh due to the fact that the motor is mounted remotely from the gearbox, and any movement on the suspension is altering the chain tension. It may have been better to have the motor mounted to the gearbox with a much shorter chain. This will not affect speed, but may be significantly quieter.

If an electric cart axle was to be used, surely a better option would be to find one with motor already attached and go with that or upgrade to a better direct drive motor designed for the axle mount.

[crash12888]

Yep, At the least need to spend some time on the calculator working out RPMS, gear drive ratios, Like you said, tire diameter even plays a factor.
Gonna be interesting to watch.

[Cartmaster]

I just edited my last post crash.

[dundeebarnbuggy]

Chains hate speed. Also the motor has to be mounted rigidly to the axle so as not to change the center to center distance when the suspension moves. How many FPM is it running? You can look up the maximum speed for any size chain on the manufacturer's chart or engineering handbook.

[bronsonj]

So your axle is 12.44:1. I would keep that axle specifically because it is not a live axle... It includes a very strong diff and is well built from the factory.

What is the max motor RPM you are getting? What is the max motor RPM that motor can safely operate at?

You said you get 60mph on the gokart. I assume that you'd be happy with half that on a golf cart. You have stock wheels so if your electric motor is limited to say 4,000 rpm then your max speed is just under 18mph BEFORE you geared it down on the chain drive.

What's the max amps/torque of that motor and what controller are you using with it?

You can use this calculator to estimate your max speed. If you go 1:1 belt drive then the rest is pretty simple.
https://www.buggiesgonewild.com/speed-calculator.php