Custom Dual Battery Setup (AGM & Lithium) in a 4-Door Jeep JK

[theksmith 3,828]

i recently rewired all of my switched and ignition-controlled accessories to run off the house battery.

 

i also took the opportunity to change out my custom switch panel and bussman relay/fuse box for an Voswitch JK Overhead 8-Switch Panel & Control Box, mainly to give me more switches.

 

 

 

here's my old custom panel & ham radio faceplate mount. i had already moved the mic down to the dash a couple years ago:

 

 

the new Voswitch panel (i had custom switch actuators made by OTRATTW) :

 

 

the ham radio faceplate got moved down near the shifters:

 

 

 

the main reason for choosing the Voswitch over all the other sPod "clones" out there was that its fuse/relay box is completely sealed (o-ring on the cover and gland nuts for all wire entry/exit). i also like that it's electrically simple - the switches all directly control the relays and there's no communications bus, bluetooth, etc. the most complicated thing on the PCB is a low-voltage cut-off, which can be disabled with a DIP switch setting.

 

 

i extended the mounting bracket for the Voswitch box to add a Blue Sea fuse box next to it for non-switched accessory feeds.

 

 

i made sure to route all the wires so that the whole contraption can be unbolted and moved out of the way without having to unhook any connections.

 

 

the Voswitch has 2 modes, it can either be always powered and then turned on/off with a little metal combo backlight dimmer and on/off button. or, it can be powered only when the ignition is on.

 

i chose to remove the metal combo switch, and replace it with a 3 position (on-off-on) DPDT rocker switch, wired so i can have the whole system ignition-switched, all off, or constant powered. the red backlighting isn't overpowering at night even on full brightness, so i'm not missing the dimmer control at all.

 

the way it comes (stock photo):

 

 

my modified version:

 

 

so far i'm very happy with this new setup. i was out of switches before, now i have 3 unused spots for future accessories, and everything is powered from the house battery as intended. i was also able to simplify the overall accessory wiring, and label all the wires this time!

 

 

Edited November 3, 2022 by theksmith

[theksmith 3,828]

just finished my 2nd multi-night adventure with this setup and everything is working great thus far. 

 

to give you an idea of the real-world capacity for a 100AH lithium battery: on the second day, we got to camp about 4pm. so starting then with a full charge - i was able to run the fridge till the next morning, run my 12v oven twice (total about 1.5 hours), and run a 12v electric blanket for a couple hours (1 hour on high, 1 on medium) - then i was right at 50% capacity when we got going again around 8am.

 

i should note it was cold out (high 60, low 40), so the fridge wasn't having to work hard. but, if it had been warm weather then i wouldn't be using the electric blanket, so things would balance out similarly i think.

 

i will want a solar panel (or 2) eventually. i'd need that extra juice if i plan to stay camped in spot for more than a day.

 

found out the small factory inverter in the JK isn't great. it failed to operate @4x4tographer's drone battery charger. the wattage rating was plenty sufficient - i think it's just a cheaper modified sine wave unit. so, i'll be adding a small pure sine wave inverter to this setup soon!

 

 

 

Edited December 17, 2022 by theksmith

[theksmith 3,828]

finally added a small pure sine wave inverter to this system. this Giandel 1200 watt unit had good reviews and was thin enough at 3" to fit between the wall and fridge. FYI, it seems to go on-sale on Amazon for about 30% off every few weeks.

 

 

it was a quick install since i'd already wired in an extra fuse holder when i first setup this whole auxiliary battery system.

 

 

i ran a 3 outlet extension up to the passenger side of my rear FrontRunner cargo area shelf to have better access to plug things in when needed.

 

 

the inverter also has a remote turn-on button, but i left that off since it's easy enough to just reach behind the fridge and push the on button when needed.

 

gave it test run with this small electric kettle and everything seemed to work as expected!

 

 

 

Edited March 1 by theksmith

[jgaz 545]

Nice job on the packaging Kris

 

Also, the bed liner you applied to your drawer front and drawer box seem to be holding up well.

Ive referred several people to your “how to” when you built the storage unit

Edited March 1 by jgaz

[WILL E 397]

I love how clean your install is. 

 

I would be careful about running that inverter at high wattage with the fridge next to it.  That's a pretty  tight space and heat might be a problem.  If your parked and the fridge is slid out then no worries.   (Although the inverter probably has an overheat circuit)

[theksmith 3,828]

47 minutes ago, WILL E said:

I love how clean your install is. 

 

I would be careful about running that inverter at high wattage with the fridge next to it.  That's a pretty  tight space and heat might be a problem.  If your parked and the fridge is slid out then no worries.   (Although the inverter probably has an overheat circuit)

 

good point. i'll have to remember to keep the fridge slid out when using it with anything higher wattage. the only thing i can think of that i would use it for while driving would be a small battery charger. the inverter has a fan in the back which seems to kick on as soon as there's a load, and there's space in front of and behind to move air, so i think it would be fine for a small load with the fridge slid in.

 

 

[WILL E 397]

Yeah, it won't be a problem most of the time.  I was thinking coffee maker, blow drying your hair, electric cooker, that kind of thing.  Most of those activities would happen when you are parked and if the fridge is slid out there is plenty of space.    I can't tell what brand fridge you have but it looks like the intake/exhaust is at the front.  So that's good.  If you had my fridge that inverter would be right where the intake is.