2018 Gem performance testing

Got my latest Gem in(thanks @Erniea15 ). wasn’t running. Pulled batteries and installed one of my Titan lithium packs. 15s, 234ah. Drove it around the block for testing and wanted to scream. Top speed of 25mph and an anemic acceleration rate. I couldn’t live with it for more than a block. Brought it back the shop , installed one of Gabe’s reprogrammed vcm’s to raise the speed to 35mph. Drove it again and MUCH better, 35mph is night and day difference to 25mph. Next step is the LG performance tune, this is where things get fun. Reprogrammed the controller to unlock the Gem’s full potential and took it out for a test. SOOO much better, this thing pulls hard all the way to 35mph, when it hit the limiter. I detuned it a little over 32mph so It wouldn’t hit the limiter too hard and it works well.

For comparison. Last week tuned a brand new E6. Set top speed to 35 and tested. It has AGM batteries and the big 6.5kw motor. With just me in it, it took 26 seconds to reach 35 with stock tune. Then did a performance tune and it did it in 20 seconds , nice improvement over stock. Todays test of E4 with 3/4 charged battery , it did it in 13 Seconds! Damn. And it has the smaller 5kw motor. Now the E4 is 350lbs lighter so that helped a little. But I’m sure that if I put 3 Bikini models in the E4 to equalize weight, it would have little difference. “I swear honey they are only for testing purposes”.

I think there is more power to be had and will put some time into it next month. Also I have Ernie’s 6,5kw motor to put in and test against. The little testing I have done on the 6.5kw motors have not shown any improvement over the 5.0kw. To be continued…


@Inwo @Erniea15 @MikeKC @twg1317 @djgabriel2004

i was a little worried about the jerking that the dealer described to you… so that was just a battery issue? nothing else wrong with it?

motor should be there Friday

Thanks for the update! Looks like i need to get up to Ted’s place and do the VCM swap

Great info LG - had the same experience with mine, drove it a block, and threw a tarp on it until spring… LOL
Looking forward to some testing soon. I have new batteries for it, Will touch base with Gabe and LG about tuning and will hit some hills - once we have all the data and testing complete I will send the gears off to Rodney and see what we can do with 12.1 vs. 17.1 gears.
Finally, a new project to get excited about.

Mine is slower (2018) than a turtle but take out my old one (lithium, bigger motor, etc.) every now and then and try to get a speeding ticket on the 101…

Yes, old ladies are giving me the finger on the flats…

Im pretty sure we can get a nice power out of the oem setup, this is just starting

Wow great results for people that don’t wanna
Rebuilt their entire car like me.

This is the battery that was installed.

Removed existing battery frame, cut a piece of plywood big enough to use the 4 battery frame bolts. Put a plastic barrier between wood and battery. Installed bottom module, offset so that cables will reach without mods. drilled holes for mounting rods

attached positive battery cable to back of bottom module

put top module in, used factory battery hold downs. They are bent so straitened them in a vice. connected 2 modules with one of the original battery cables in front. connected Neg battery cable to top lug. Turned on BMS and everything works.

Covered with supplied battery cover. That’s it, pretty easy install. Current charger setting will charge to 56v, will range test at this voltage initially. And then install my plug in device to raise voltage to 60v(may go to 61v), test again. Last Gem went 70+ miles, want to see if this Gem will do the same.


That was the shock to me when I drove a few new GEMs compared to my 2013 with your Lithium battery upgrade. Mine can almost spin the tires when I take off, compared to the new ones which are way too tame. Once you have a real fix, I’ll buy one and convert it!

The fix is in.
Only a matter of degree.
Speed/power upgrade is reprogramming, only. Works better with lithium, like everything.
Performance takes proportionally more battery power.

Full monty is 72v conversion. Don’t spend the money on repro if hv upgrade is in your future. Not needed for hardware upgrades.

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I have done multiple of both and they are pretty close. I think personally I’m going to keep a newer Gem and sell my 2014 classic Gem.

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This is a full hardware conversion diy install. Took some doing as client has high speed gears. Every car needs a different tune for motor size, voltage, and driving style.
Matt didn’t like the aggressive regen I use normally in my cars.
He is up north with me and could not do much testing since fall.
Tesla 24s 25kwh toolbox battery. A full 1/4 of a Tesla. 88.8v nominal. He requested something bigger than his hero @grantwest Grant. :slight_smile:
Oem 5kw motor.
Aftermarket Sevcon S4 controller.
@djgabriel2004 motor on the way, maybe.

"Decent weather meaning 35ish degrees with the sun out. Moved the cars out of the driveway and took Gemma off the rollers. Backed her in and out of the driveway just to test it. All was good so I went down my street and was gentle getting up to 25-27mph. She seemed good so I got a little more brave and got up to 35mph.

No bucking on deceleration. Just a nice even pull when accelerating. The more you stay in the pedal the more it goes goes goes.

When you let off the pedal you just slow down naturally like a regular car. I think it may be perfect."
Matt B.


There is a swaybar joke here somewhere.

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@Erniea15 is putting “speedbox” #0001 in my stock E2. He should be doing a review soon.


Great! I was so underwhelmed by the acceleration and power in the new models with the stock setup, compared to my 2013 with LithiumGod’s reprogram and battery upgrade, and since my wife doesn’t like the look of the MikeKC’s Tesla battery on the floor, I have to go another route. Grant said he’s getting some in pretty soon too. On another front, what are your thoughts on the guy in Scottsdale, Devin with Elevate Designs? My wife likes the paint jobs on some of his stuff. I told her that I’m not a big fan on the giant lifts they do.

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Greetings, I have a GEM E4 2018, it does not charge, I bought 8 batteries, it does not show the percentage of the battery and the fault light comes on when I see the code 520508, a 7 on the left side of the battery and on the right a church key and on the top right 1me can you help please

If you bought different batteries than OEM you have to reprogram the charger. To match with your new batt chemistry.