Gem car lithium batteries?

GEM Forum
22

It’s dooable. How much do you want to spend though? You’re going to need a new motor controller and a high speed AC motor, new tires and rims that max out the wheel wells, ideally Li-Ion batteries, and depending on what year GEM you start with, maybe a new charger that can be programmed for Li-Ion and you might have to swap the gearbox for one with taller gears.

10-35_23_8500
10-35_23_8500974×827 105 KB

8-9_23_8500
8-9_23_8500951×810 102 KB

About 1.21 jiggawats.

Right gearbox. Wrong cart though. 00-04 the gearbox is mounted certerline on the vehicle, so you might not be able to fit some of the hi-revving AC motors that have been used around here before, I believe most are too big and too long. Also, 55 mph in an 02, you’ll probably die. The brake are shyt, they are drum all on all 4 wheels and when you step on the brake pedal, it’s more of a request than a command. The suspension is garbage, it’s single arm design, and it kind of counted on the 100-120 lbs of flooded lead acid batteries that sit over the transmission and motor, if you ditch that weight, the front end kind of wants to pogo-stick. The steering is a mere 2 turns lock to lock. Not so good for an overgrown golf cart going warp speed on city streets. Stock battery charger not compatible with Li-Ion.

And then there all the other issues with 99-04 years.

So, by the the time your are done un-fracking the '02, you will likely be in deeper than had you started with something much newer. And it will still be a piece of crap. Just a really fast piece of crap.

23

Dude. Stop right there. Wrong platform. Don’t use the e2 if you want to go that fast. The wheelbase is wayyyy to short. Coupled with the 2 turn Lock to lock rack and pinion steering it will be insanely twitchy.

  • Not to mention the next to zero suspension.
  • It sounds like you know about the lack of proper brakes.
  • Anything pre 2005 is not going to fit any decent sized motors. Forget about stuffing that 8KwAC motor in there unless you really like making right turns only.

Use that little magnifying glass tool in the upper right of the screen and with a few choice keywords you get into the archives and find the guys that have gone fast(but NOT 55 fast) It is not fun, Not practical, NOT cheap, and over the borderline and rapidly heading towards death trap.

If you get a chance to look at one real close (even a newer car), take a look at the suspension. I’m not sure which engineer thought it was a good idea to model after a go cart and/or a quad. These are not real road cars. There is no adjustment to getting the wheels aligned except for toe-in. The cars were basically hand build and welded and not very accurate.

Not too long ago- a wise forum member put it into ultimate perspective

IMO - You need to seriously think about reviewing your build goals and if they still hold fast, then you should be looking into a nice used Bolt or even a Fiat 500e. You would probably be into it for cheaper than what it would take to mod a Gem to do what you want it to do. These are designed to do freeway speeds, has 90 mi range, brakes, Air conditioning, and a heater.

1 Like
24

Okay maybe I should rephrase what Im trying to do. I wanted to find an overall cheap electric car. Something I can fix myself. And insurance is a huge part of the cost that I am trying to lower. I was looking into older electric cars but I can only find the Citi car by Sebring vanguard, because it can be registered as a classic vehicle and would be cheaper. The gem seems cheap overall, insurance seems cheap, and in theory I can just stick with lead cells since I don’t need much mileage. I really just want a cheap electric car that’s easy ish to fix and it’s pretty hard to find one in ny so I thought, f*ck it, the gem is cheap, and can be made faster. Maybe it’s possible to make it go 55 for when I’m on a main road and 40 the rest of the time and pay very little in insurance, and in a few years the 02 will have classic status making it even cheaper. I guess I’m trying to find the overall cheapest electric car that is easy enough to fix that with some electrical knowledge and research I can do it myself, so something with parts availability, preferably with tools for scanning them available as well.

25

Rodney has a lead bottomed DC drive 2001 e2 that can hit 50+ so it can be done, but it’s not for everyone. One thing about Rodney is that he almost certainly knows more about the 99-04 years than anyone out there, including the designers. Everything on his is modified, including a motor that he personally reworked and you shouldn’t even be able to fit in the vehicle. Even his T1 or T2 controller has been reworked from 300 amps to 500 amps to handle that ginormous motor. (post 04 controllers are 400-500 amp)

It’s very easy to make any classic (original body style which lasted until around 2014 IIRC) GEM go a little bit faster. Adding up to about 10 MPH is a snap, costs less than $200 and takes mere minutes to do. All you need for this is a way to bypass the maximum speed setting of the controller. Get a “magic magnet” from Dave @Inwo, plug it in to the motor’s speed sensor output wiring and you’re done. Or get a programmer and raise the maximum speed in the controller, not all controllers have this parameter available for user adjustment though.

Getting past that 35 mph-ish stock hardware limitations gets progressively more complicated, time consuming and expensive though.

First off, you’ll need more juice. This means adding more batteries or swapping out for a whole different battery technology. You can stick with marine batteries for the lower cost, but it quickly becomes diminishing returns after the first +1 because of the extra weight. The 7th battery hack plus the governor max speed adjustment or tricking should get you into the low 40’s. Lithium will give you even more juice, 90 volts + at 1/4 of the weight or less. Less weight = more speed.

Past that, you’re into math and money, especially considering you are trucking around 500-600 lbs of ballast.

Larger tires will get you a bit more speed, but your acceleration will suffer. 02-04 had 10.35:1 gearboxes, 99-01 had 8.9:1. 8.9:1 will give you a better top end, but your tire options are limited. Too tall and you’ll launch like a snail on Quaaludes.

The DC motors are not high revving. The stock DC GEM motors are only 4100 RPM rated. The ones used from 99-04 are these itty bitty anemic things that can’t handle much more than that. DC motors for the GEMs tend to nameplate in the 4100-5k range. An R$F blue is rated at 5k and you can spin it all day long at 6k-ish, with bursts to about 7k. Other motors can be modified to do similar or more, but the 99-04 doesn’t have room up there for them unless you start moving shocks around or adding wheel spacers. AC motors on the other hand, 8-9k RPM is a piece of cake if you have room for the long motor (which the 02 does not)

I’ve hit 42-43 in my old 2002 eL (truck model). 7 batteries, reprogrammed controller, R$F blue, stock tires. Damn near flipped it on a corner though because of the lame suspension design. Immediately reprogrammed the controller to max at 37 mph.

If you want to take 10-12 mph off your top end requirement, then what you want to do is mostly achievable the way you want to do it. But you better find a good 02-04 to do it on or you’ll be pouring money into that sled to keep it running.

26

BTW, if I were in an area where the rolling cheese wedges were that available, I’d be tempted to get one and do something ridiculously stupid with it., like stuff a hayabusa motor in there. Maybe add some retractable outriggers so it doesn’t tumble over on a turn, paint it white and stencil Galileo 7 on the front quarter pannels.

27

If you’re wanting to drive an average of 40-45 mph, I don’t think a GEM is the way to go. Too dangerous in my opinion. Especially a pre-2004 model. It’s going to be unstable, which might get you in an accident, and you get in an accident in a gem going 45+… Slim chance you’re walking away. At that point, you might as well just get a motorcycle or a scooter.

Btw - I tried to get a 8kw motor in a 2000 gem. No way you’ll get it to fit without some serious modification. Only person I know that pulled it off was @bundcur but he did it by installing a 2005+ frontend.

28

I’m Kind of surprised that the suspension hasn’t collapsed yet from hauling around the weight of Troy’s gigantic bronze balls. @MikeKc told me about that cart when he went out to custom tune it. Apparently 45-50 is just barely getting warmed up for that cart. It is insanely fast.

29

He cut the front off an 02 and put on a 2014 front end. Kept the 8:9:1 gears - It is a 65mph car now.
Crazzzzyyyyyy.

30

So in theory putting a new gearbox, ac motor and controller, into a post 2004 gem and redoing the suspension? And getting a lithium battery pack? Hmm. Wonder what that adds up to in parts.

31

Who in their right mind would want to go even over 40 in a GEM? Our 2001 with motor and lithium battery upgrades tops out at about 40 and we call it Mr. Toad’s Wild Ride. Over 35 and your life is clearly at elevated risk.

32

Correction → Over 40 in an early e2.

33

I ride a 250cc Enduro year round so :man_shrugging: seems like less danger overall. I mean Mr toads wild ride is fucking hilarious though.

34

Do any of you know of a conventional electric vehicle that’s cheap overall and easy to work on?

35

You know what they say. “If you have to ask…”

Lithium and AC drive could easily run you upwards of $4k. Less if you build your own Li-ion pack, but if you’ve never done it and/or didn’t design the pack or system right, you could be in for a carbeque.

36

Sounds tasty, but do you know of a more conventional, less tasty, vehicle that’s cheap? Also if I wanted to replace the battery modules on a Nissan leaf how would I do that? It looks like you just jack up the Nissan, drop the pack like a gas tank with a separate Jack under it, move it out, and somehow open the pack ??? Replace the cell, and whatever. Anybody wanna like direct me to what I’m supposed to do maybe? And where to get modules cheap and off good quality?

37

replace the battery modules on a Nissan leaf how would I do that?

Even tho the collective minds here are pretty smart, I think you might get a better response if you ask this Q: in the correct forum. Most people here would not be reinstalling things back into a Leaf.

https://www.mynissanleaf.com/

38

You lost me at “jack under it”.

Phrasing.

1 Like
39

Lol. Jack haha. :wink: .

40

A gem is considered a LSV (Low speed vehicle) so even if you decide to take the risk and mod it to go 55mph you can only drive on streets posted 35mph or less. Forget about hwy.

41

but if its from 02 i can register it as a custom vehicle after 25 years and ignore all safety regulations though legally speaking and also get cheap af insurance. which was the goal in a few years since its old as hell.