Dual battery setup with old battery?

[007]

I know that it is wrong, and I think I know why, but I purchased a diehard platinum series exactly one year ago and I'm thinking of using it with the one I just bought for a dual battery setup. (to avoid the $189.00 purchase)

If I understand correctly, the new one will be brought down to the old ones level of performance.

Other than that though, no other harm will be done correct?

Also: Is the National Luna kit still the way to go for a guy that wants to keep this simple, painless and cost effective?

When all systems were compared in the magazine I was leaning this way, just not sure if I'm missing out on something new and great.

 

[jasondavidmann]

You are correct, if you wire your second battery in parallel (12V) or in series (24V) the batteries will balance themselves.

Why are you installing a dual battery setup? If you do not need the increased amperage (parallel) or the 24 V (series) but are only using it to power lights, fridge etc.. why not install a battery isolator, the batteries will not even know that each other are there.

 

[chasespeed]

I agree.... unless you are using it for starting, ISOLATE IT.

Another option...use in conjunction with an isolator.... grab one of those Marine 4 way battery switches.... #1, #2, Both, or Off.....

What is the purpose of the 2nd battery?

Chase

 

[007]

Thanks for the replies!

The purpose for the second battery is to power a fridge, heater, lights, laptop and winch.

I doubt I would need to combine often, so if it makes the wiring more simple and reliable I could keep them isolated.

My big concern is just making sure I have enough battery to start the truck, I don't want to depend on my memory to toggle things on or off to do it either.

 

[ntsqd]

Given the use I'd suggest looking at one of the "Voltage Sensing Relays" or "Automatic Charge Relays". These run under to slightly under $100 and are automatic. They sense when the starting battery has been fully recharged before charging the Aux. battery, and they sense when the alternator has quit charging to disconnect the Aux. battery. West Marine carries Blue Seas' ACR and Del City Wire carries BEP Marine's VSR.

Coupled with a marine battery switch as suggested above (normally set on "1") will allow you to self jump-start off the Aux battery or otherwise force the two batteries to be paralleled should that be necessary. BEP offers a combination of their VSR and one of their battery switches in more or less one unit.