New to Gem: Bought 2002 E825 for hilly area

Hi all -

Bought a used 2002 E825 4-seater that needs a bit (lot) of love. The batteries were replaced Feb/March 2020 and the previous owner said it’s been “chipped” for extra speed. I hit about 30-35mph on flat roads. I live in a really hilly area. Yesterday I started with 100% battery, went down and around, probably 1-2mi total, and on the uphill, the speed dropped to 15-17mph. Then came the error -41 (motor overheat). Let it cool for a few minutes and continued on, but at ~10mph uphill max and she was struggling. After about 20 minutes of driving, the battery showed 45% charge.

So now the embarrassing questions - where do I start? I’ve read old 2015/2016 threads about lithium, motor upgrades, transmission upgrades, etc. but there seems to be conflicting information.

How can I find out what was “chipped” and if it’s the right option for my circumstance?
How can I tell what transmission I have now?
What’s the best “bang for the buck” to get better hill performance?
What order should I do the upgrades to maximize impact?
I need new tires anyway & have friends in the wheel business - what size would you recommend (looks like 4x100 pattern)?

Thanks all!

Just bought the disc brake upgrade kit from NEV Accessories, still looking for advice on the original questions

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I think this is the controller?

And the motor

And 6 of these batteries, dates feb/mar 2020

0613-00863 is the part number for a 12.44:1 This is probably a better transmission choice for hills than the original 10.35

Looks like a T2 controller. Stock for that year. Easy to bump up the max speed, there is a setting for it in there.

D&D 7.5hp motor. Also sold by R$F. 5k rated rpm, can spin 6k all day long.

4x100 is the lug pattern.

Most of the stuff has already been done to your cart. Best bang for performance at this point is lithium batteries. You’ll have to weight down the nose though, the 99-04 need weight up there for traction.

Awesome thank you. What size wheels/tires would you recommend?

Is special equipment needed to bump the T2 max speed setting? I haven’t been able to find details about accessing the ui (just to send it out for programming)

If you are hitting 35, you are already probably as fast as you will go and overspeeding the motor quite a bit in the process with that 12.44

You would need a programmer or sentry software and the proper cables to get into the controller. I’d guess you have the standard R$F tune on there that came with the motor.

As for tires / rims. Shrug. You aren’t going to be able to stuff anything much taller than 23-ish under there without it hitting. Tall tires aren’t going to do you any favors on hills either.

99-04 steer, stop and ride like shitty deathbuckets. I’ve done 40-41 in an 02 truck model. Damn near flipped the fugger on a turn. Turned the top speed down to 35. I don’t mind dying, but in a golf cart would be embarrassing.

Welcome to the group mkmkmk. Are you one of the lesser known and perhaps the 5th stooge? That was more of a nyuk-nyuk-nyuk tho.

Yeak-ok. I’ll keep my day job.

It looks like you have a bunch of good stuff. As you found out, if you are going to be running in the hills you need to build a car for them. If you are going 30-35 on the flats I’d say either your controller has been cranked up, you have a Magic Magnet external device installed, or the D&D motor has a speed magnet installed inside. Is your speedometer correct?

Thanks for posting all the pics.
Those numbers on your trans look like it is a 12.44 gearbox. This is odd because a '02 normally came with a 10.35 trans. You might want to count the turns and verify what gearset is in there.
The motor has been upgraded to a D&D/ and looks like a 7.5 torque motor which is good, but member testing has shown these motors don’t really like the heavy loads of a big car and hilly areas.

One thing you haven’t mentioned is the size of tires you are currently running. I know you said you were thinking of upgrading but you probably shouldn’t be looking at bigger(overall) tires. If anything, smaller would help.

Also- A real crafty hack might rig up a small fan on the motor to help keep it cool.

If you look hard enough, you might be able to find a 14.76 trans but they might be rare.

You can keep an eye out for a GE7hp fan motor which would be ideal. This is also a pricey option.

Unfortunately all the bang for buck tricks look like they have been applied.
The next level is going to cost you.

Given an unlimited pocketbook, Lithium would be a good direction, but also adding an AC motor swap would be the ultimate package for your needs.

You win the statement of the day!!!
:rofl: :laughing:

I don’t think those will fit in the 99-04. They are pretty long. The 99-04 the transmission was dead center. In 05 they moved it over to the side for the bigger motors.

You can move a shock to shoehorn the long GE5 in there, but I think the fan cooled 7 is even longer.

Oooo- Good point!
I keep forgetting about the limits of the early cars.
If his trans has been swapped it might fit? Am I wrong about the 10.35 gears in the early cars?

Also- maybe the R4F programming needs to be looked at? It could be generating excessive heat that shows up on hills. Not enough field?

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The D&D is a pretty good motor.

Besides installing the NEVA brakes, all that this cart really has left to do to it is lithium batteries and new meats. Hilly + performance, it’s kinna dialed in already IMO.

The 14,whatever trans will suck the life out of the top end, but if you need to climb a tree with it…

You guys are awesome. Thanks for the great info.

Where does one go to buy the lithium batteries in 2021?


I can set you up depending on your budget. Are you in love with this car? The drawbacks of the early gems are many, and expensive to overcome.
I’ll let someone else list them. You found out about the brakes.

-41 is not motor temperature. D&d motors do not generally have a sensor. Your controller is overheating, so you are at the limit of performance with what you have. Imo.

Grant tells us that it takes $10k to get an early car tricked out.
New big motor, controller, and light weight battery will set you back ~$5k. And worth every penny. BUT, it won’t stop safely and will ride like a lumber wagon.

As mentioned previous, there is not room for a big motor, unless it has the new offset gearbox.

Can’t wait. :grin: I’ll list a few.
Brakes and steering are pretty awfully.
Suspension only works if you have 500lb of lead on board.
Big motor won’t fit easily.
Charger and controller are in an oven under the hood.
Rear control arm is designed to fail.

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2005 plus model… @grantwest

Would something like this help keep the controller temp down?

12V Electronic Cooler Semiconductor DIY Refrigerator Cooling Radiator System

Yes and no. The heat needs to go somewhere.

Inwo is right! I should have looked that up. -41 is Controller overheat which is totally different. There are a few tricks that can be done to help that. The cooler plate you listed is an interesting thought but a little overkill. It also adds to your power load.