Dual Battery setup

Not only does this cat make a fine isolator he also has a slightly modified '79 K-10

Helroaring's products looks good.

I planning on doing the same modifcation, however, I've having a tough time find a good location to mount the second battery.

Do you have any thoughts on this? Where are you mounting the 2nd battery? I have a Chev Sub 97, 454.

Let me know if you have any insights.

The best way is with a heavy duty relay. They are available many places, like golf cart shops. They look like a Ford starter relay but they are different internally. If you need help with the circuit, let me know.

The Diesel batteries are hard wired together. If you leave the lights on they both die. On the newer trucks the computer shuts the lights off if you forget them on:)

Al

We have a 100 car fleat at work with dual batteries. one under the hood, and one in the truck for the radio and computer equipment. (can not start the car with the second battery) They are set up with a heavy duty relay. and since the cars are run 24/7 on and off all day and night, the relays wear out ofter a while. the manufacturer changed the relay contacts from silver to some other metal. Just by not having the silver contacts, the relays last half as long as the older ones. so make sure and get a top end relay of you go that route.

Go to Pep Boys and get an isolator rated at the amperage your alternator puts out, or higher.

Wire as indicated.

Get a Ford starter solenoid and wire the positives of both batteries so that each mains terminal goes to one of the batteries.

This gives you ultimate flexibilty. If you need a jump start, just activate the solenoid via a switch you installed in the cab, and you're able to jumpstart yourself!!

Have done it on every truck I've owned and several folks in the Jeep club's vehicles. Works like a champ, for about $100 of materials including cable .

Sorry Al-- the best way is NOT to use just the relay.

If you go that route and lose the alternator, you kil both batteries. Plus, over time, they will fight each other and damage the cells.

After running dual battery cars at work in a 24 hour operation, the batteries have laster over six years, both in the trunck and under the hood with a relay setup. I really dont think we have anything special, just a deep cycle battery in the trunk for the Radio and computer.

agreed

you should wire a setup that disconnects the unused battery. i used to wire them for friends using ford solenoids to switch off and on to the battery i wanted to use/charge.

john

Battery isolators are just large diodes. The forward voltage drop changes with current. A relay is better any way you look at it. Years ago I did this for a living, we used RBM 375 relays. RBM is now owned by Gould if someone didn't buy them out. The 375 could handle a lot of current and was dead reliable. It's easy to wire in, just one wire from the ACC terminal of the ignition switch, easily found in the fuse box, and some wire and it's done. No need to cut or splice any of the original wiring. If you think an isolator is better, tell me why.

Al

my 96 k2500 w/5.7 has dual batteries and they are wired together. I would get the second tray from a junkyard or dealer and a new positive cable from NAPA. The ground is just a ten gauge wire screwed into the drivers side fender. There is no isolator from the factory and my truck fires up fine in the winter (Indiana)