Homebrew Single Group 31 Battery Install (1 Viewer)

TeCKis300 · Jun 23, 2020

Took a cue from this thread and ordered a high quality Deka 1131PMF battery. It's a flooded lead acid which has the advantage of full compatibility with the stock smart alternator charging profile (and longest life prospects). With often sought features of AGM including:
- Spill proof
- Heavy duty full frame construction (claimed 20x stronger vibration resistance)
- Heavy duty plates for 2x better extended battery life (and therefore better deep discharge capacity while maintaining good battery life)
- Deep plate envelop pockets to increase life and reduce likelihood of shorts
- High current ratings (low internal resistance that likely also improving charge rate)
- ~30% more usable capacity

Best of all, easy to source from Lowes, and an excellent value proposition at $140 (-$10 core) shipped.

Mounting kit is available from Slee. I opted to roll my own.

1) Tray
- Trim stock tray mounting nubs half off closest to engine side, to allow tray to move over 3/8" to accommodate the wider frame of the group 31 battery
- Trim tray lip closest to the fender side, allowing the batt to span over the tray. There's a risen part of the sheet metal underneath that will perform as the locator for the battery towards the fender.

2) Battery Terminals
- As many group 31 have centered terminals and need a battery terminal extension.
- Made extensions from ring terminals butted back to back, with a short segment of 4 gauge wire. Many metal ring terminals can be crimped with large adjustable pliers. And/or soldered with a propane torch.
- Added these to military battery terminals in the following configuration and it was a perfect length

3) Hold down clamp
- Modify the two bends in the stock hold down bracket close forward radiator support. Goal is the bring the mating surface lower and parallel to the radiator support. Easily done with a vice and monkey wrench (for leverage). Wrap bracket with a towel to minimize scarring.

rusty87 · Jun 23, 2020

You’re on a roll!

mcgaskins · Jun 23, 2020

Any chance of the stock terminals working?

TeCKis300 · Jun 23, 2020

Yeah, could make stock terminals work. Though the posts on those start off about 1/2" off the deck and wouldn't lay as nice on top of the batt. There would be two pivots on the vertical axis making it not as stable at the right angle brackets where the cables mount. Vice the military terminals that that puts one pivot on the horizontal and triangulates to a vertical post. If that makes sense.

Any particular reason for stock terminals?

I'm on a role with mods as I'm deciding to keep the LX for at least a few more years past when the cybertruck launches. Might as well mod it now and enjoy it. And perhaps hold onto it for longer still.

eatSleepWoof · Jun 24, 2020

Looks like a good setup!

I have a few nit picks as I'm usually super paranoid when it comes to electrical:
- I'd use heavier gauge wiring; no technical reason that I can reference, but 4 gauge seems a bit small for such a critical location/use, even when doubled as you've done it. (Anyone know stock wiring size?)
- Crimping with pliers - any pliers - can lead to issues. Again, for such a critical use, I'd absolutely use proper crimpers, and then solder overtop as you've done.

Bookmarking for future mods!

TeCKis300 · Jun 24, 2020

eatSleepWoof said:
Looks like a good setup!

I have a few nit picks as I'm usually super paranoid when it comes to electrical:
- I'd use heavier gauge wiring; no technical reason that I can reference, but 4 gauge seems a bit small for such a critical location/use, even when doubled as you've done it. (Anyone know stock wiring size?)
- Crimping with pliers - any pliers - can lead to issues. Again, for such a critical use, I'd absolutely use proper crimpers, and then solder overtop as you've done.

Bookmarking for future mods!

Good points and allow me to postulate.

Wiring gauge requirements is also a function of distance. The cross section of these two short segments is plenty. Evidence that they are sufficient would be that they are larger in cross section than parts of the OEM conductors which are just stamped sheet.

Yes, agreed that crimping with pliers, depending on how it's done can be suspect. Use a long 12" plier, and the throat to crimp. For your reasons stated, I'd say do at your own risk. Just know I've got several crimpers on hand and I've crimped many many thousands of 4 gauge terminals in my time. Having produced grounding kits for various car models many moons ago and never a failure. Soldering is a solid option too that can be done with a standard propane torch.

BigMF · Nov 25, 2020

Alright @TeCKis300 , I guess I'm just going to have to move to San Diego. That way, when you do a mod that I'm going to end up doing 6 months later, I can just drive over and look at yours.

I WAS leaning towards the AGM route but really don't want to deal with having to buy a trickle charger and then remember to hook it up occasionally. I'd much rather do work once and let it roll. The savings of getting the $130 Deka battery plus $10 terminals versus the $430 battery PLUS $120 charger PLUS $50 diode gives me back $460 to put towards a bumper or fridge. Sweet!

TeCKis300 · Nov 26, 2020

The mod bug bites. Glad to help your mod dollars go farther.

Just car camped at Death Valley with my family of 4. I had no concern about the Deka doing its job. In and out all evening with doors open and a lot of power and lighting use. Got down to 37 degrees. Deka is always charged with no extra complexity, and held it's own with plenty of reserve by next morning.

sdnative · Nov 26, 2020

TeCKis300 said:
Just car camped at Death Valley with my family of 4.

View attachment 2507211
View attachment 2507210

Apologize for getting off topic, but can you share more detail on your tent setup? Is there a thread with more detail? Assume you have to leave the hatch open allowing heat to escape? How did that work with temps in the 30s?

CharlieS · Nov 26, 2020

BigMF said:
Alright @TeCKis300 , I guess I'm just going to have to move to San Diego. That way, when you do a mod that I'm going to end up doing 6 months later, I can just drive over and look at yours.

I WAS leaning towards the AGM route but really don't want to deal with having to buy a trickle charger and then remember to hook it up occasionally. I'd much rather do work once and let it roll. The savings of getting the $130 Deka battery plus $10 terminals versus the $430 battery PLUS $120 charger PLUS $50 diode gives me back $460 to put towards a bumper or fridge. Sweet!

Seems like a reasonable approach, just don't lull yourself into thinking you are getting all of the capabilities of a dual battery system. Minimally, I'd consider adding a Noco or similar to your shopping list, so you can self jump if your single battery dies.

TeCKis300 · Nov 26, 2020

sdnative said:
Apologize for getting off topic, but can you share more detail on your tent setup? Is there a thread with more detail? Assume you have to leave the hatch open allowing heat to escape? How did that work with temps in the 30s?

Happy to. I've gotten criticism from this forum that's it's not "overlanding" looking enough, but it works. Excellent with 2. We slept a family of 4 (kids 6 and 10) that night which is tight, but warm enough with with everyone cozy inside.

Here's a thread:

Car Camping, Rear Hatch Tent and Window Screen

I took my own advice from this other thread, and tried out a rear hatch/tailgate tent this past weekend. I go weekend camping very often with my kids through the YMCA father/daughter and separately father/son program, so it's just two of us at a time. Hard Shell Roof Top Tent vs Camping...

forum.ih8mud.com

TeCKis300 · Nov 26, 2020

CharlieS said:
Seems like a reasonable approach, just don't lull yourself into thinking you are getting all of the capabilities of a dual battery system. Minimally, I'd consider adding a Noco or similar to your shopping list, so you can self jump if your single battery dies.

Yes, this is key to have a portable jump starter for safety when remote and I do carry one. It is something to think seriously about. My setup has all accessories on a SwitchPros which has a low voltage cutoff for another measure of safety.

I would also temper the benefits of many of these classically installed dual battery systems as their integration is questionable with a lot of complexity, that in and of itself, could create reliability problems. This is how I would do dual batts for those that need more expanded reserves.

The single Deka is capable with solid reserve, but it is true that it won't power certain things depending on what one wants to power. My dual battery setup comes in the form of a portable Goal Zero 1000, which is arguably more capable than traditional dual batts, as it has lithium power density and high power inverter capabilities (1500W). We normally camp in my Airstream, which the Goal Zero also does double duty in. Straying away from my travel trailer base station for segments of backcountry travel, I pop the GZ out and use it in the car. Using it with a electric coffee maker and electric George Forman to re-heat premade meals in 10 minutes. When camping with the guys, I prefer propane and real cooking, but with a young family, convenience was important.

BigMF · Nov 26, 2020

CharlieS said:
Seems like a reasonable approach, just don't lull yourself into thinking you are getting all of the capabilities of a dual battery system. Minimally, I'd consider adding a Noco or similar to your shopping list, so you can self jump if your single battery dies.

Thanks for the input. I do have a portable jump starter that I always carry. I think it's Nocco but can't remember the brand without going out to look at it. Also, like @TeCKis300 , I'm planning on having a portable power station as well as solar down the road.

Bunga · Nov 27, 2020

Just a quick personal experience on the jump packs. I had a cheap Cosc_ one that worked great once and completely failed the second time with a full Li charge. No sweat, a buddy rolls up with this beautiful Noc_ boost, same deal. Won't provide enough power to spin up, but luckily we have jumper cables, then spins up fine. I think it comes down to state of charge. I run dual battery now. But for weight savings, a set of cables seems critical.

BigMF · Dec 4, 2020

Hi @TeCKis300 , just picked up my Deka from Lowes this afternoon. I believe I have all the parts described above to work on my new battery this weekend. I guess the only thing I'm not 100% clear on. It looks like you just bolted the existing battery cables to the two short sections for each terminal. Is that correct or am I missing something? BTW, that battery is heavy!

TeCKis300 · Dec 4, 2020

Ayup. That's exactly right. It's as your picture shows and closest in mockup to the ground terminal here. Sorry I didn't a pic of it in place.

Heavy's good for a lead acid batt - that's the first indication that's there's a good amount of lead in the construction for durability and long life.

Ratchey · Dec 4, 2020

BigMF said:
Hi @TeCKis300 , just picked up my Deka from Lowes this afternoon. I believe I have all the parts described above to work on my new battery this weekend. I guess the only thing I'm not 100% clear on. It looks like you just bolted the existing battery cables to the two short sections for each terminal. Is that correct or am I missing something? BTW, that battery is heavy!

View attachment 2515432

That is how I did it. Made 4 jumpers from 3/8s and 5/16s wire lugs and 4 ga wire. I also used large split wire loom to cover all of the exposed positive connections.

What have you done to your 200 Series this week?

Tested the roof rack on the 200 series. It’s a beast. For real I finally made a long time dream come true with a lift. Now I get to start a massive re-organization, but that’s ok. I’m a happy man. I think I may grab a cold beer, sit in a chair and stare at my lift LOL.

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You can see the connections @TeCKis300 made here