Durable Dual Battery Setup

by Greg Banfield

A friend of mine, Bill Mish turned me on to this setup a few years back.  This system was easy to set up, cheap to install and has lasted over the years.  I originally went down and bought an isolator and it never seemed to work right.  Plus, I wanted a system to double the amps to the starter or the winch, I wanted to be able to choose which battery to charge, I wanted to isolate all my accessories to one battery and have just the motor stuff run off of the other one.  This system has worked great.  The one thing I did while I was there, was to run 1 gauge and 1/0 gauge wire to everything.  It instantly doubled the rpm of my starter on start up, and for those long runs across the engine compartment, you can't beat the 1/0 gauge for not losing any amps to the winch.  The beauty of this system, is each battery pulls itself up by the switch.  You can run dual batteries (parallel) or pick which battery you want to run.  If you have questions about this system, just drop me an e-mail or post it to the EBML.  Hope this helps!

  • Original Starter Solenoid (Free, already there)

  • 2 Constant Duty Solenoids ($6.00-$12.00 each) (Cole-Hersee Part# 24082)

  • 2 Lighted Switches ($1.99 each)

  • 1/0 AWG and 1 AWG wire with 3/8 crimped eyelets ($20-$30 dollars for the good stuff, make your own)

  • 2 Batteries (already have one at least, 2nd Battery ($35-$2000.00)

  • 12 AWG wire for the switches (I am sure you have some somewhere in the garage, if not $2.99)

  • Miscellaneous electrical connections (eyelets for solenoid, spade for switches, etc. $1.00-$3.00)


_Solenoids _Fuse Block
This is how I arranged the solenoids.  The blue one is the factory solenoid.   Don't get confused here.  The two constant duty solenoids apply power to the + side of the starter solenoid.  Nothing changes there.  Your accessories, alternator and bat power are still in stock locations This is the remote fuse block I put in to run all the accessories.  I can pick which battery to power it when the truck is off or on.  I will blast the stereo and use BAT2, then when I go to start the truck I will use BAT1.  Then while I am driving, click ‘em both on for charging.
Dual Battery Schematic

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