2015 E6 vs 2021 E4 hill climbing

I have a 2002 gem that climbs hills very well. Need more room so looking at 2015 E6 or 2021 E4 with bench seats. Planning on switching
either one to lithium batteries but can I find motor for new Gem to climb hills or do I need to buy the 2015 E6?

Ask @grantwest .
He has a new model hill climbing 50mph Gem.
It’s all about your budget.

Either cars 2015 or 2021 will convert to Dave’s
High Voltage performance kit. Both cars will need almost the exact same equipment so the cost of the Upgrade will bet the same

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Where do I find Dave’s high voltage performance kit?

They are custom built depending on vehicle.
Parts for big battery, motor, controller can get near $5,000
For over 35mph on 2016+ add transmission by others.
If budget is an issue, we might be able to cut some corners.
Or if you are near a member who has done a car previous, may save some support time and money. Ca. Fl. KC

I am in San Diego California and would love 35 MPH up hills so lithium batteries motor and controller for sure. Worried if I change gears might be fast on flat but unfortunately I live on big big hill. So hill speed with family is most important.

My 4 passenger 2002 with large lead acid batteries and motor/controller upgrade does 30 up our big hill. So my goal would be the same with new 2021 car that can hold all 5 members of my family.

I would not change gears unless you need more than 35mph. This is for 2016 plus Gems.
I have been testing my 2018 ELhd tonight. Bone stock using the 6.5kw oem motor and new controller.
Runs 35mph nicely and same mild performance as before controller swap.
I believe the new Gems work well on hills. See if you can get a test drive.
Then with the controller swap for 35mph and lighter 60v lithium batteries, hill climbing will improve somewhat. Certainly no worse.

If this works, it will be much less work and money that the total hotrod upgrade.
Drop in a battery and swap controller.
Recommend finding a Gem with the big motor, as that’s what I’m testing.

This speed mod should have much more torque available to unlock once battery is swapped out.
The limiting factor is battery range which plummets at high speed and hill climbing.
Time permitting, I’ll throw in a 65v Goliath battery and see what happens.
@grantwest reported an uptick in performance at 60 volts.

Worth every penny I’d say!

I’m out in San Carlos if you want to check out and drive my 2016 e4. Still working out one last bug but runs fine cruising under 40. which hill are we talking about?

an e6 for 5 people is going to be heavier.

We live at the top of Mount Soledad in La Jolla and the kids school is at the bottom. The amazing part is no one has ever mastered this hill climb but with a few failed attempts ( ok I have been towed home 15 times) we now have our 2002 E4 flying up the hill with the whole family at 28MPH which is awesome.

I have the del Cerro hill to get up and over to get anywhere. On my 2000, before I went nuts with upgrades, I did ok with the D&D Ride 4 fun motor and T2 controller in terms of speed. My issue was range and heat in the summer. I had cheapo marine batteries and once those started to degrade, I couldn’t make it up and over and back. Voltage sag would kill me.

You definitely have some stable and viable options to make either of those cars you’re looking at rip up the hill. Just depends on how much $$ you want to throw at it.

Don’t think there’s a bench seat option for the new e4s. They are bucket seats. You’d have to get something built or do a rear flip up seat where the trunk goes.

I’m still learning with the help of the forum and not as blackbelt as others, but willing to help if you go down an upgrade path.

My car… It has the 8kw motor, 80v sevcon S4, 12:1 gears, and a telsa 20s battery. More than welcome to check it out. Also, in a month or so… @smspring will have an almost identical setup and he lives in your area.

thank you everyone for all the help. Looks like a 2016-2021 E4 with custom bench seat for my 3 little kids is the best direction for me. Can I come see both your cars in Del Cerro and San Carlos if your both up for some teaching to me. My number is 619-251-7167 My goal would be lithium batteries, a controller and a larger than 6.5kw motor if needed to get 35 MPH top speed and as many hill climbs as possible before needing another charge. I haven’t found any used ones available so looks like I will be ordering new which I am ok with because we use our 2002 everyday and love it.

More than welcome to come out East and check out my car. heck, I could even drag it or drive it out there to see how it does up Mt Soledad!

Food for thought - @GHTransport on the forum has moved a bunch of stuff for folks on here. Super reliable, fairly priced, friendly, etc. Search nationally and you might find a deal on a used 2016+. I bought mine from a dealer in St. Louis. Since I was the first non-dealer owner, it came with a full warranty… which I’m sure I voided by ripping out the controller, charger, differential, and battery :rofl:

@Inwo @MikeKC @LithiumGods will have all the parts for you.

If you want a turn key GEM, @grantwest would probably build for you.

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I do try and keep up to date on this forum for sure, I have notifications turned on so anytime I’m mentioned and tagged, it pops up on my phone.

So if ever need anything moved, let me know and I can make room for it. Usually give better discount to people who are referred through this forum as I have a lot of returning customers that refer me on here.

Shoot me a tag on here, or a private message if ever needing anything. Thanks!


Want to sell your 2002?

Not yet, I use it daily until the new one is built. I will keep you posted.

HI Kevin, Richard here in Washington State. I too have a 2002 E4. We have hills to climb. My issue was not enough power as it had a 3.5 HP motor. I got a 7.5 from old house boater. Lots more power and speed but we’re still getting -41 code which is over heating. Just one question what motor do you have in your E4 currently? Curious too, your batteries are what make?


The overheating issue went away for me when I got the ride4fun motor. Seems to run collier or handle the heat of hills better. As for batteries we tried everything and after many many battery types and sizes these are way better for hills for me, unless your ready for the cost of lithium which I believe would be way better if you don’t mind the cost.
Motive T1275 plus
150 ah @ 20 hours


-41 is a controller overheat, not the motor. The R$F motor I have in my 02 doesn’t even have a temp sensor, and it’s been a while since I looked, but I don’t recall that there was even a plug for temperature on the harness.

Assuming the GEM isn’t heavily weighed down, check for dragging brakes, poor or corroded contacts at the battery, controller and motor power connectors (the large cables) and also if the controller is mounted properly and the back is making good contact with the aluminum plate under the dash. Some people have had success unbolting the controller adding thermal heat sink paste to the back / bottom plate of the controller and bolting it back in.

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