Dual Battery Setup

Ok Im in need of a little help or input....

Im planning on hooking up dual batteries and currently have a red top as primary and a yellow top to service all the needs in my cap/bed area. Using an ATO battery tray.

My question is what gauge wires should I use to connect the batteries together and what would be my best system to control battery charges? Im not looking to spend a ton of money and I'm really just looking to put an isolator or VSR to regulate both battery levels.

Any recommendations on proper gauge between batteries (2ft max) or brands of isolators or VSRs?

2014 Tacoma Sport 4LV6

 

I use the ML-ACR
https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A
and 00ga wire to connect the two with a CB on each end of the wire.

 

http://forum.expeditionportal.com/t...ke-a-cheap-isolated-dual-battery-setup-for-50

 

I concur on the ACR and would suggest nothing smaller that #4 wire. Welding supply houses have this in a very flexible cable as well as the necessary lug terminals.