I'm sure this is another dumb question....

[banksy70]

I really appreciate the help you guys have offered on a bronco I purchased a few weeks ago. The latest dumb question is - what is this a picture of? It's not on but I'm not sure what will happen when I turn it on

https://ibb.co/hsryXm

 

[bknbronco]

dual flux capacitors.....(aka batteries)??? maybe you got 2 batteries and it runs some relay setup?

 

[okie4570]

Single or dual ejection seats, 007 kind of stuff

 

[AZ73]

What's "mer on" Maybe if there wasn't a black dot covering it we could help more. Whatever it is, it isn't stock.

 

[Slowleak]

Dual battery switch....
https://www.4x4groupbuy.com/store/wranglernw-dual-battery-tray-jeep-9706-p-4988.html

 

[thegreatjustino]

Dual battery switch

 

[AZ73]

Dual battery switch....
https://www.4x4groupbuy.com/store/wranglernw-dual-battery-tray-jeep-9706-p-4988.html

WOW that's pricey.

 

[Slowleak]

WOW that's pricey.

That’s what I was thinking...

 

[Rustytruck]

maybe it comes with jeep?

 

[DirtDonk]

Center position Dual OFF is where the alternator just charges the main starting battery.

Left position Dual ON lets the alternator charge both batteries equally. Likely no regulator to let it charge each one as needed, so it's up to the user (imagine that! a manual selector of all things!;D) to only turn it on when needed to top off the auxiliary battery.

EMER ON is the best feature actually. When activated it literally jumps the main starting battery with the auxiliary battery. So when your camping refrigerator gets left on overnight and the truck won't start in the morning, flip of a switch and you're back on the trail/road.
Very handy that.

Paul

 

[DirtDonk]

The Painless ain't exactly cheap either at $220 (https://www.wildhorses4x4.com/product/Painless_Standard_250A_Dual_Battery_Kit/Bronco_Batteries), but if you're building your own it's a good place to start.

Paul

 

[ntsqd]

There are, I think, better ways to do this sort of thing (ACR/VSR + Marine battery bank switch, @PKYS for ~$115 Note that the 120A is charging current limit, not a starting current limitation). But since that system is already in place and I assume working correctly I don't think I'd change it.

 

[RPM289]

That's cool! I was thinking simple a Drag car cutoff switch in power cable between 2 batteries and a 12v wire hot when lights are on ran to charge 2nd battery when running.