Off-Grid Engineering Dual Battery System Q&A

I run a pair of Odyssey batteries side-by-side in the stock location with the OGE tray. Mine are 25-PC1400 and

$378 35-PC1400 T Automotive and LTV Battery

35-PC1400. Its an old tray with the plain strap so I don't know how the newer machined ones work, if the relief is correct. This strap isn't all that secure, though, so regardless of fit it's not a great solution anyway. Also, use Loctite on all the fasteners since they like to loosen with vibration.

 

Anyone use a HKB voltage booster fuse? I bought and installed one to up the voltage to better charge the AGM batteries but am seeing a full 1v increase instead of .5-.6v as advertised. I emailed Leigh at HKB who responded saying the cold temperature compensation (-10°F when I installed the fuse) from the alternator is why the voltage is going so high (15.2v) which makes sense from how I understand our alternators to work. Is there any concern with having the truck run at those voltage levels form tended periods? The battery charger I use to charge/maintain the batteries in the truck, motorcycle and four wheelers starts charging at 16.8v and I’ve never had any problems so I’m inclined to believe that 15.2v won’t be a problem.

 

Thanks - I got it figured out and it probably goes against what others did.

I went to Napa yesterday and put two Optima yellow tops side-by-side and the tie down didn't fit - almost, if I had wanted to grind off part of the plastic I could have made it fit. I pulled two Group 35 Napa Legend batteries off the shelf, set them side by side and the tie down fit with a little play - so I got two Napa batteries for about $250 less then Optima and $300 or so for Odyssey. For my use case I think this will be fine and I am not worried about drawing down the house battery significantly.

Today I finished the install (except the remote switch) and the truck started which is awesome.

I had a message on the dash saying to check the charging system - this went away and I let the truck run, restarted and it didn't show up again so not sure what that was about. If anyone has seen this before and knows what it could be please let me know, I am guessing that the truck was sensing lower voltage in the main battery being new?

I was worried about messing up something on the install and I think it worked out OK so anyone looking for info on how to install from someone that was worried about it just let me know and I can tell you how it worked on my 2018.

 

I think you should be fine as it seems to depend on temperature, for example another manufacturer makes a similar voltage booster (arclightLEDs) that allows you to adjust the voltage output (+.5v or +1V FOR COLD TEMPS) in case you are worried about it spend another chunk of change and buy this one. *Note: I personally run the one that toyo22r sells on ebay and have had 0 issues with it and it has made alternator voltage MUCH better for me and my charge hungry batteries.

 

hmm. trying to install my tray tonight, but running into an issue where only 2 of the three holes for the fenderwell studs will line up, and the third one fouls on the support leg. any idea why?

 

The aux tray will fit on those studs but you have to really finesse it in there. It took me a few tries before I got mine fully seated on the studs and all other holes lined up.

 

That looks good!

I had some issues with the passenger side tray when I was installing mine. If I set it down flush on the bottom surface, the fender mounts didnt line up. And visa versa. Ended up stacking maybe 3-4 large fender washers up under the "cup" looking piece. Fills the gap between the tray and the fender, so the weight of the batter is still fully supported, but I can also lock down the two bolts into the fender as well. Now that my install is fully complete Ill try to post some pictures here at some point this week

 

Heres a few pictures of what Im talking about. Had to stack up 4 fenders washers (same O.D. as the "cup"). Applied some never seize to each one, and dropped the battery tray in place. With those 4 washers it was a nice flat fit between the three mounting holes on the bottom while still allowing the two fenders holes to line up.

Another note for anyone who reads this before installing their own split system kit. Instructions say to leave the fuel resistor plugged in. But its actually way easier to unplug it (wipe the dust off the connectors first), screw it to the tray, install the tray, then re-route the wires and plug them back in.

 

Sorry to hear you had problems getting that tray in. Believe it or not, I've seen his happen before and Ive also seen the exact opposite happen. That leg actually used to be a 1/4" longer but I shortened it due to being too long on most trucks.

I believe there are small variances in every truck produced that prevents me from getting a 100% perfect fit every time. Anyway, thanks for heads up! This is the data I use to make small changes every now and then.

 

No worries. Im sure there are variations in every truck. Imo better too short and having to add a few stainless washers than too long and being screwed.

 

Can the dual batterrry set up on opposite sides accomidate 2 group 31M agm batteries then?

 

Hey @SR-71A did you just push that duct work over? Mines crossing the tray corner and idk how much I can push it. Don’t wanna bend it or mess it up.

 

Thats a wire harness going into the cab. You should just be able to push it out of the way.

 

That wiring harness is very flexible and will end up resting against the back of the plastic battery housing. No worries about damaging it.

 

Sorry. Not enough room or strength in that fender to safely carry a group 31 on the passenger side. The recommended battery size is Group 35. If you need more auxiliary power, try rerouting your starter cables to the passenger side to make the Group 35 your starting battery. This leaves room for a Group 31 auxiliary battery on the drivers side.

 

@HeliMedic and @oni06 thanks

 

Group 31M has no problems on drivers side. I had one in my 08 for 2 years and it ran amazing. I guess I'll measure to be sure and I'd add a cage to passenger side to distribute the weight. I'm probably good with th 31M solo honestly was just interested. Thanks for the info either way.

 

No problem. A Group 31 fits absolutely fine on the drivers side. That was my recommendation.

The passenger side location lacks the room (mostly in the later model 2nd Gen and 3rd Gen trucks with the air pump) and the strength in the fender to easily and safely carry a Group 31 on the passenger side. Im sure if youre a handy fabricator, you can make it happen, but it was not necessarily the goal with my auxiliary tray.

 

I was wondering if its possible to do 2 different size batteries, I was thinking of doing a group 31 for aux power and 34R for main battery.

 

Sorry for the late response man I was out all weekend. Yeah I just pushed it over a little. Looks like it's a tighter fit on the 3rd gens, but should be doable