Dual Battery Links
Painless Wiring
Hellroaring Electronics
Hellroaring Electronics - PICs & Install Info
Wrangler Electronics
Optima Batteries
Help for dual battery set-up
Below is a description of the site above...
Both batteries have their negative terminals to frame ground.
The stock battery positive wiring stays as is except another cable must
be run from the pos terminal to one Heavy Terminal of the solenoid. The
positive of the second battery goes to the other heavy terminal of the
solenoid. Now if we turn on the solenoid the batteries are in parallel.
The switch determines how we turn the solenoid on. There is no non
technical term for the type of switch but the guys at Radio Shack will
point you to it. It's a Double Pole Double Throw (DPDT) with a center off
position. RS part # is 275-1533 It's priced right at 1.99 in my 97 catalog.
OK this switch has 6 terminals in 2 rows of 3 1 2 3
4 5 6
Terminal 2 will go to one of the small terminals on the solenoid. The
other small solenoid terminal goes to ground. Your solenoid may have only
1 small terminal. In this case the case acts as the coil ground and you
only have to hook up the positive from the switch. Back to the switch.
Terminal 1 will get 12v from an IGNITION source. This wire must be hot
when the key is in START as well as ON. Voltage in wires on the accessory
leg will drop out in the start position. Thats why your radio dies as you
crank. We need to keep the solenoid on in start so we get the cranking
power of both batteries. Terminals 3&5 get wired to the positive terminal
of the 2nd battery. That's it for the solenoid control wiring.
Therefore if we leave the switch in center off we have separated
batteries and the truck functions as if it was stock. If we put the switch
in the 1&2 position the solenoid closes as soon as the key is turned on and
stays that way til the truck is turned off. The alternator will charge both
batteries and you will draw from both. The 2&3 position is "Self Jump" If
you left your lights on or something like that the 1st batt would be dead
and there wouldn't be enough juice to turn the solenoid on. But since term
3 is powered from the isolated 2nd battery it will close the solenoid,
"jumping" the dead batt w/ the 2nd. Terminals 4&6 are for indicator lights
if you want em. One side of each light is grounded and the other goes to
term 4 or 6. If you don't want indicator lights you could either Use a
single pole switch or jump across the rows to double up the rating of the
switch. The only downfall I can see is you're still screwed if you leave
the lights on and leave the switch in self jump. That's life I guess.
You can probably source out a suitable solenoid for under 20 bucks at
any forklift shop. Just tell them you need a 12 volt lift solenoid (tin can
type)for an electric pallet jack.
This information was given to me by Mike Taliento.
I take no credit for this information.
Thanks Mike,
Corey
© 1998 coreyperez@hotmail.com
