2020 GEM e2 upgrades?

Continuing the discussion from 2017 35 mph install video:
Hi Dave:
Grant has suggested you may be able to help with my thoughts to purchase a 2020 GEM e2 - more specifically upgrading to a 8kw motor and higher capacity battery package. These all in addition to changing the gear box to Rodney’s 12.3 package.
Any input or options you can provide would be most appreciated!

I’ll have to put it back on Grant. No more testing until a break in the weather. I have a virtual new 2018 E2, that I bought just for testing.
Got as far as putting the big 8kw motor on.
What are you looking for performance wise? Polaris offers a big lithium battery. Seems it’s about a $10,000 upgrade. Is cost an issue?

Hi Dave:

Thanks for the timely reply.

Having previously owned a brand new 2005 e2 - which I recently sold, my primary goal with a new GEM is having the capability to travel at
least 35MPH. My 2nd goal is for a reliable round trip travel range of 25 miles.

My very first upgrade back then was the RFF 7.5HP with 14’ rims. As you well know, the otherwise max OEM speed of 25mph is just fraught with well-deserved roadside humiliation.

After consuming 3 battery packs and 2 sets of tires in 14 years of use I managed to rack up about 10k miles. In that time span I found that a travel range of 25 miles was adequate . . . in most cases. Admittingly, there were more than
a couple of times I prayed the green turtle would guide me back home. In that connection, about 5 years ago in the quest for longer range, I forayed into the installation of a Li-ion power system. The end result was a long, unsuccessful and costly learning
curve with me capitulating back to using a standard GEL battery pack.

So to answer your question about my appetite to fund performance upgrades, I’m comfortable to modify the gear box (estimate ranging from $650-$1,250) to increase the max speed to 35MPH. I’d gladly entertain the cost of a 8KW motor if it
allowed a speed closer to 40mph. However, with an average mileage range usage of only 25 miles between charges, a cost of $10K for the Polaris’ lithium option is impractical for my needs. I’d consider spending $2K-$3K for the comfort of a proven and trustworthy
alternate battery package that would extend my travel range to 30-40 miles.

While currently traveling out of state, my timing is to order a new 2020 for factory delivery to coincide with my return back home in mid-March. As part of assembling a factory order, I need to anticipate which after-market options I plan
to install. In that way I can minimize the cost of those OEM components which will be immediately replaced with these upgrades. In the example of planning for a post-market 8kw motor, it would be wasteful to order the factory upgrade option to their 6.5HP
motor. Likewise, it would be foolish to order the extended battery package knowing in advance that a more efficient post-market option was available at an acceptable cost.

In any event, I look forward to learning how your expertise and experience can help in selecting which upgrades will best accomplish my goals of attaining a speed of at least 35MPH along with a minimum range of 25 miles. Hopefully the timing
of placing an order for mid-March delivery will coincide with improved weather conditions that allow you further progress with your testing. In the alternative, I have no qualms in delaying my 2020 order in anticipation of your eventual completion of testing.

In the meantime, it would be helpful if you might share the experience with installation of your 8kw motor.

Thanks again for sharing your knowledge - Greg

Unless you have deep pockets, I would wait for Grant to get his done.
Where are you located?
Warranty is an important part of a new car. That will be gone with the first major modification.

12:35 Gears effect range. I don’t have the data to back that up but i Can tell you with confidence if you wanna go 35 for 25+ Miles your gonna need a bigger battery then stock. If you have hills even more so. The 8k motor is gonna cut into that as well. Where are you located? Are u in the flats or a hilly aera

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Hi Dave:

I’m in southern Louisiana with nothing but flat prairie for half the state.

I accept the loss of manufacturer’s warranty that comes with the upgrades -inasmuch as I would never consider buying a vehicle that only goes 25MPH anyway.

Is your caution relating to deep pockets predicated on a 8kw motor needing the power afforded by the Polaris $10K battery option?

To better understand the requirement for deep pockets, are your thoughts along the line of offering an assembled completed vehicle with all the upgrades necessary to meet my travel needs?

What’s a ballpark level of the amount you have in mind and for what components?

Thanks for your patience in trying to get a clearer picture of your thoughts in how to proceed forward with possible upgrades to a 2020 GEM.



Hi Grant:

Thanks for the info.

Being located in southern Louisiana, the closest thing we can claim as a hill are the system of man-made levees. Otherwise, this part of the state is pancake flat for hundreds of miles.

I look forward to installing an 8K motor as well as supporting it with a properly configured battery pack that will adequately meet my travel needs. [As clarification to your reference of needing a “bigger battery than stock” does that
include the Polaris Distance AGM Battery package of six 8 volt batteries rated up to 60 mile range?]

However, I have hesitation stemming from Dave’s caveat about needing “deep pockets” and the reference to the Polaris lithium package costing $10K.

It’s not a matter of affording it - but rather a poor value for me when comparing the cost to the derived benefit. That level of investment would make more economic sense with needing a range of 90+ miles.

I sincerely appreciate your input in helping with my effort to configure a 2020 factory order that will anticipate after-market upgrades. In that pursuit, I’m agreeable to either buying the necessary components from you; or in the alternative
offering a consultant fee for your effort.



My mention of cost and warranty is a back door way of selling mine after I get it set up the way you want.
I have a feeling it would be the same or less cost, than new, set up the way you want it.
I only bought mine to help others with figuring out the ac powered Gems. Once I get Grant squared away, I plan to sell it.


Awesome looking car Dave! I did not realize that colors other than black or white were available.

Thanks for your clarification as I now understand the basis for your comments. Your suggestion to follow through using Grant’s efforts appears to be the simpler way to proceed forward.

Best of luck in completing your testing.


5 to 8" of snow coming down now, or I would be working on it.
There is no guarantee of performance beyond what grant has now. But a >12kwh battery for more range should be doable.
I have the 8kw motor in now. Can’t drive it, so I have no idea if I can coax any more power from it without swapping to a larger controller.

Thanks Dave:

Do the >12kwh battery pack + all other needed ancillary conversion components comprise the items totaling the $10K you previously noted for the battery upgrade?

If so, I’ll probably just upgrade the gear box and order the 6.5HP motor & Distance AGM package option offered by Polaris.

With my maximum travel range being only 25 miles, it’s hard to justify the added cost associated with an 8kw motor.

That’s Polaris pricing. Might be near $12k.
About $3500 for Grant’s 12kwh upgrade.
That is if it carries over to the new Gems.
$10k-$12k would buy my complete upgraded E2, if I ever get it done.
The only path for that is through Grant. Him getting his done and me sending him mine. Things move slowly in Mn. :wink:

Does the $3,500 include all the ancillary components to make it functionable?

[Brrrrrrrh – MN. sounds cold! Thankfully enjoying winter in Maui – along with the visiting whales

Yes, for the battery upgrade. An estimate from doing legacy gems.

This estimate based on brand new components in converting to a <12kwh battery pack w/ 8KW motor to include {or not?} a convertor, charger, BMS – or any other parts? [I’ve seen mention of a “contractor” but not sure if that’s the same as the convertor.]

No, not even close to a real estimate. If you need something right away, better to not wait for me.
The batteries would “not” be new. Mine are from a near new Chevy Bolt.
The Leaf batteries just listed for sale are supposedly new.
It would take ~35 tandem cells to equal a 2p15s Bolt battery. About 1/2 the money it there is room in a new Gem.
Unknown seller and no support though. A better deal for someone who has done lithium upgrades before.


  1. Polaris warranties their Brammo lithium for 30K miles/5 years. If I own a GEM for 15 years averaging 700 miles/year while needing a maximum travel range of 25 miles - do you think the Brammo battery would continue to provide adequate charge for my needs for at least 10K miles?
  2. In such a case, the initial cost of $9K for Polaris lithium would be less then the 5X replacement cost (every 3 yrs. over a span of 15 yrs.) of $12K for AGM 6V batteries ($300 X 8 batteries every 3 years). I use the 3 year replacement cycle based on my 15 years of using GEL in my 2005 E2.
  3. I’m ignorant as to how lithium batteries age with time as compared with the depletion rate of GEL’s considering # of charge cycles, SOC, passage of time etc. I see where regular lithium EV cars post life spans of at least 100K miles.
  4. So it’s reasonable to assume the Brammo lithium could readily have a useful life of 10K miles - just not sure about how that plays out when extended over 15 years??