# GEM eL XD Truck - Upgrades - Lithium, R4F Motor, On-Board Solar Charging, 72v to 110v Inverter, Lights

**URL:** <https://community.electricforum.com/t/gem-el-xd-truck-upgrades-lithium-r4f-motor-on-board-solar-charging-72v-to-110v-inverter-lights/15895>\
**Category:** GEM Forum\
**Created:** [April 20, 2019, 8:15pm UTC](https://community.electricforum.com/t/gem-el-xd-truck-upgrades-lithium-r4f-motor-on-board-solar-charging-72v-to-110v-inverter-lights/15895 "2019-04-20T20:15:45Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![GEMRIX](https://avatars.discourse-cdn.com/v4/letter/g/bbe5ce/32.png) [@GEMRIX](https://community.electricforum.com/u/GEMRIX)\
**Post date:** [April 21, 2019, 5:47am UTC](https://community.electricforum.com/t/gem-el-xd-truck-upgrades-lithium-r4f-motor-on-board-solar-charging-72v-to-110v-inverter-lights/15895/7 "2019-04-21T05:47:13Z")

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@Tyson_Davis, your install is pretty slick!

In my GEM truck there is one large battery tray that had more than enough room to hold all 6 of the original group 31 batteries clustered right next to each other with room to spare. The battery tray measures 22.5" wide X 31.75" long with at least 14" of height clearance. The front half of the tray is directly under the seat and extends back under the truck bed.

> [@Chevy lithium batteries for Gem](https://community.electricforum.com/t/chevy-lithium-batteries-for-gem/13922/30):
>
> 14" wide 34’ long ~5" high.  
> Room for two in a truck.
> 
> ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/b/bbbe30de024d2f525540edc0145ed0f2a59c3e5c.jpeg)

> [@On another topic](https://community.electricforum.com/t/15871/5):
>
> I put a 36" long battery in my truck. Only need to cut the back of tray out. About a 16" piece of the rear flange. Replace the cutout piece with aluminum angle.  
> Or even a flat piece under or over.

Either way would work but I decided to go with the split & stacked configuration for the following reasons:

- Save space toward the front of the tray for other electronics that I plan to install where they will be best protected by the seat
- Keep center of gravity low and in the middle lengthwise
- Grant’s video as referenced above
- Split & stacked like firewood, another popular source of stored energy… really this is the modern classic approach
- Should be easy to install because the underside of the truck bed is hollow with an access door on the top as well
- I plan to enclose the battery itself and the attached BMS in some sort of water resistant box. Perhaps something as simple as a plastic bin with a rubber seal will work so I can still show people that nifty battery pack.

 ![Ziploc%20Bin](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/8/89899efe58ee33d5746e7e7c7a5134e2ede57a61.png)

This particular bin is 19.70"L x 15.75"W x 11.02"H according to the listing. On Amazon, the Q&A section said interior bottom is 19 x 15. At the top 20.5 x 16 and 10.5 deep. Presumably the split and stacked configuration would be 17" long X 14" wide X 10" high. @Inwo, please verify actual assembled dimensions including “feet”. It may be best to mount the BMS on the original end plate.

This is the long answer to a simple question and @grantwest gave a slightly more concise answer while I was typing this. This is my thought process.

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