Dueling Batteries: A dual setup on my 07 LX...

[v_man]

What's up OB, I'd like to share my dual battery install. Much of the info is copied over from my LX build thread, but I'll add a few more pics and details here...

The impetus for the dual was that I wanted to run a 12v fridge in camp and I wanted redundancy in my ability to start my truck.

Challenge number 1 was clearing a space in the engine bay for the 2nd battery. I did this by relocating a power steering reservoir and a few other electrical components.

Next I had to create a tray for the second battery:

What you see is a tray for a Yellow Top Optima that has attached side trays for a BlueSea auxiliary fuse box plus a spot for the necessary circuit breakers. The entire tray was built to mount to the curved interior of the LX.

 

[v_man]

There are numerous types of solenoids available for connecting and disconnecting batteries. The range is literally a $20 dollar solenoid at AutoZone and a $500 computer controlled electronic marvel that senses your every thought and anticipates your mood and when and where and why to disconnect your batteries.

I found a happy compromise with this $70 unit on Amazon. It's user controlled, as in there's nothing automatic about it, more about that later....
https://www.amazon.com/gp/product/B001YIPXR2/ref=oh_aui_detailpage_o01_s02?ie=UTF8&psc=1

The next task was to find a spot to mount the solenoid and the switch that controlled it. Here's where it landed. I like that I can hear it engage and disengage with a very satisfying click...

Next I mounted an in-cab switch to control the solenoid....

The connecting and disconnecting of the two batteries is completely user controlled. Obviously when you're in camp and the vehicle is off, you want your starting and house battery disconnected. But I also wanted the the option to wait and connect the batteries after the truck had been started, thereby giving the starting battery a chance to recover a starting discharge. I guess it all comes down to the fact that I'm a huge control freak and I needed the ability to do whatever I wanted with my two chunks of lead and acid. The only "uh-oh" scenario is leaving the two batteries connected after the vehicle is turned off thereby providing an opportunity for both batteries to become discharged, but I'm hoping to create a habit of always checking the switch every time I exit the vehicle....until then I'll carry a jump pak around...

 

[v_man]

The last step was to wire every thing up. I went with 2/0 gauge welding wire for my main cables. I added the yellow wire sheathing just for looks....

Then a few circuit breakers later, a relay here and there, and a generous helping of zip ties and it was all over...

A few other details: Total cost was anywhere between $600 and $800, that includes a new Yellow Top and a new group 27f Bosch starting battery, also included in that cost was the solenoid, 3 circuit breakers and the Blu-Sea aux box. Voltage drop between the two batteries with the car running is less than .02 volts. Total time to setup was several hours a day for about a week. Total beers consumed during install: quite a few. Number of times I accidentally sparked both battery posts with an errant wrench: 3.

 

[Delete Me]

Questions:

1. where did you run the ground for the new battery? pretty dang hefty I might add.
2. batteries wired in parallel?
3. looks like you put a circuit breaker on feed side to 2nd battery and on feed side of fuse panel. your thoughts here?
4. why not energize the dashboard switch only when vehicle is turned on? add a relay on feed side to switch.
5. nice dashboard switch. LV doesn't come with upfitter switches I guess. Nice. I guess not a question.
6. what circuits are you running off fuse panel?
7. did you add 12v outlets in rear of LV or ... ?

Thanks, -FB

 

[v_man]

1) the 2nd battery is grounded to the starting battery
2) batteries are wired in parallel so when connected it's like having one large battery
3) there's a circuit breaker between the 2nd battery and the auxiliary fuse box. The aux. box is rated to carry 120 amps so it needs a CB to protect that. And yea there's a CB between the solenoid and the 2nd battery that basically just acts like a quick disconnect for the 2nd battery. I like being able to completely disconnect the 2nd batt. and the aux. fuse box from the rest of the vehicle electronics
4) The switch controls the opening and closing of the solenoid. So the batteries can be connected wether the car is running or off. I wanted to be able to connect the batteries in the off chance I needed to run a winch when the car was off, or not starting for some reason. Plus if the starting battery ever dies I can connect the two batteries together with the switch
6) So far I'm only running a 12v plug in the rear for our fridge, but extra lights, a HAM radio, more power ports, an inverter etc. will all run off the aux. fuse box
7) yup I ran a dedicated 12v power supply in the rear of the vehicle for the fridge...

 

[HeliSniper]

This looks way professional.... I like your thought process as well... Only 3 time arching the terminals? You're a better man than I.....

 

[v_man]

This looks way professional.... I like your thought process as well... Only 3 time arching the terminals? You're a better man than I.....

ha, it might have been four , thanks...

 

[interscope8]

Excellent info here, going to have to pick up that BlueSea box for my 2nd battery install when I get to that!

 

[ABQruiser]

Reviving an old thread. V_man - Would you mind sharing pictures of the clearance and/or how you designed around the power steering reservoir? Did you have to relocate the reservoir? TIA.

 

[Magic Mike]

The last step was to wire every thing up. I went with 2/0 gauge welding wire for my main cables. I added the yellow wire sheathing just for looks....

Then a few circuit breakers later, a relay here and there, and a generous helping of zip ties and it was all over...

A few other details: Total cost was anywhere between $600 and $800, that includes a new Yellow Top and a new group 27f Bosch starting battery, also included in that cost was the solenoid, 3 circuit breakers and the Blu-Sea aux box. Voltage drop between the two batteries with the car running is less than .02 volts. Total time to setup was several hours a day for about a week. Total beers consumed during install: quite a few. Number of times I accidentally sparked both battery posts with an errant wrench: 3.

Very clean, nice work

 

[RickR]

Nice job, look great.

 

[OverlandGX]

Doing this asap, thanks for the write up