Hi everyone. I am looking to add a second battery for my truck. I chase for the Baja 1000 (and others) so at times I have the motor off and the radio on and even maybe the work lights. Being in Baja and chasing for a race I can't run into a issue where the motor is dead so having a second battery is just a good idea.

I picked up one of the Ford Battery Tray's on Ebay (http://www.ebay.com/itm/FORD-OEM-VAN...-/221310584664) and plan to use that.

My question is how do I wire it in. I see lot of setups using relays or solenoids but because this is an occasional thing I was thinking that using a typical boat selector should be adequate. I was planning to pick this guy up:

http://www.bluesea.com/products/6006...th__Knob_-_Red.

That way I just leave it off unless I absolutely need it and then on my way back to the states I can leave it on to make sure both batteries are fully charged by the time I get home.

Am I missing anything? Thanks

 

Looks like you have it covered, just make sure it's wired parallel, also see how RV aux batteries are wired to get an idea

13 FX4 sterling grey scab

 

RV aux batteries generally use solenoids to isolate the 2 batteries, and the house power comes off the aux battery. When the engine is running, the solenoid allows both batteries to charge.

 

I looked into the solenoid method but they are triggered off the ignition. Most of my accessories require the ignition to be ON which defeats the purpose. That's why I am looking at the manual switch method.

Here is how I am wiring it...



I will put the switch and fuse between the 2nd battery positive and 1st battery positive. Is 100amp enough?

 

Why not run a battery isolator set up? It will automatically charge both batteries and you can determine what each does without drawing power from the other. Put the radios and lights on the second battery and the other as the starting battery. I have run that set up many times for competition audio. The nice thing about is when you use the accessories it wont draw from the starting battery. The other nice thing about it is if your starting battery dies because of headlights or some other oops, you can give yourself a jump from the secondary battery.