Dual battery setup question

Hey Guys,

I have an 84 chevy k10, and am trying to install two batteries (pos to pos and neg to neg). I've been told that I can install a solonoid in the positive line that when I turn on the ignition, the solonid will engage (like an old ford starter solonoid), and connect both batteries (basically to run a winch from the second battery). I've installed a solonoid from a 95 ford pickup, but the solonoid gets real hot when its engaged. I can only touch it for about 20 seconds before I need to let go, b/c it is hot. I am not using this solonoid for what it was intended, I know.. but have you guys ever heard of this type of set-up before? and if so, what kind of solonoid should I be using?

Hey Guys,

I have an 84 chevy k10, and am trying to install two batteries (pos to pos and neg to neg). I've been told that I can install a solonoid in the positive line that when I turn on the ignition, the solonid will engage (like an old ford starter solonoid), and connect both batteries (basically to run a winch from the second battery). I've installed a solonoid from a 95 ford pickup, but the solonoid gets real hot when its engaged. I can only touch it for about 20 seconds before I need to let go, b/c it is hot. I am not using this solonoid for what it was intended, I know.. but have you guys ever heard of this type of set-up before? and if so, what kind of solonoid should I be using?

starter solenoids are designed for a short time of operation..the coil of the solenoid is creating the heat..

you could try placing a droping resistor in the coil feed to reduce the voltage to 6volts..

search for a dual battery isolator

Thanks for the input guys. But how do the battery isolators work? will they let the alternator charge both batteries in the vehicle?

Thanks for the input guys. But how do the battery isolators work? will they let the alternator charge both batteries in the vehicle?

PST-SBI-3112 is a componet that isolates and connects two batteries used in a system with what appears you have ..

the main battery with this product has charging priority...when the slave battery drops this componet connects the main battery to the slave..

when starting both batteries are connected..this device costs about 90.00.....

to avoid any surge damage always connect the battery grounds to the same ground stud...........also the loads being driven need fuses current limiters.. this device has a limit of 150amps @12volts dc...

You need a continuous duty solenoid. They look just like ford starter relays but they have a metal housing instead of the black plastic. Most auto parts stores can get them, a few keep them in stock. Find out the amperage draw of the winch and multiply by 1.5 to find the capacity of the solenoid you'll need. Make sure you fuse the positive cable between the batteries, and make sure the cables, positive and negative, are at least the same gauge as the ones on the vehicle. (Most likely 2 gauge or 0 gauge.) Should be able to find the solenoid for around $30.

Master,
Would this be the right choice?
http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611784830

Or should I get something like this?
http://www.colehersee.com/catalog_top/index.htm

If I went with the first one, would it put more of a strain on my alternator?

Master,
Would this be the right choice?
http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611784830

Or should I get something like this?
http://www.colehersee.com/catalog_top/index.htm

If I went with the first one, would it put more of a strain on my alternator?


the one I mentioned is much better, fully automatic and can handle 150 amps..

the alternator is gonna be given two batteries to charge, this is added load...no way to avoid this fact..if it is a problem you can get an external voltage regulator, this increases alternator capacity/life.

solenoids would not have any effect on the battery..unless if you went with the manual switch control and forgot to shut down the solenoid., with the engine off..

The Grainger site solenoid is only 85 amps, the Cole-Hersee site defaulted to their home page. If you opt for a solenoid that will handle 150 amps continuously, it would handle starter amperage, thus allowing you to use both batteries when cranking. The two smaller terminals on the solenoid are what energize the relay. One goes to ground, the other goes to a vehicle circuit that has battery voltage when the ignition is in the RUN and CRANK positions. You can add a momentary SPST switch under the dash and power it from the aux battery. The additional switch will allow you to start the vehicle from the aux battery if the main goes dead. I used to work for a company that modified vehicles for the physically challenged, this is the set up we used. Simple, inexpensive and extremely reliable.