quick question

[lowriderram_95 10+ year member]

so I was thinkin about somethin, when adding a second battery could you not just run a wire from the alternator to the second battery? the way I was thinkin about doin it was remove the big 3 up front, leave the factory wire from the alt to the front battery and run a wire from the alt to the rear battery. would this work? if not why?

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[Tone415 10+ year member]

why would you wanna do that? JW

 

[fbi90909 5,000+ posts]

It will and technically both bats will still be wired together as 1 being that they are both connected at the alt. You should just run it from batt to batt

 

[lowriderram_95 10+ year member]

I'm wantin to do it this way mainly to save a little money. I've got a spare battery that I could build a sealed box for it even tho the trunk is completely sealed off from the cabin so no fumes would get in. but the reason I was wantin to do this is to get away from using a battery isolator since the batteries won't be the same. I just thought this would work and so that I won't have to use an isolator.

 

[fbi90909 5,000+ posts]

You're not goin to end up with isolated batteries. They will still be wired together being that both batts are making contact at the alt. If you want to isolate your battery then get a battery isolator.

 

[lowriderram_95 10+ year member]

I wasn't tryin to isolate the battery, I was trying to get away from using a battery isolator. so would it work or not? this is all I need to know

 

[c_b_ 10+ year member]

it will work. and it will eventually perform very poorly. your batteries, if left un-isolated, will wear each other out, causing premature failure.

 

[SPL Blazer 10+ year member]

it will eventually perform very poorly. your batteries, if left un-isolated, will wear each other out, causing premature failure.

How do you figure this?

 

[SPL Blazer 10+ year member]

Myself and quite a few friends of mine all run two or more batteries and never waste money on a battery isolator. The only reason for using one of these is to allow you to run your system with the vehicle off and not kill your main starting battery. If you don't plan on doing demos with the vehicle off then you have no reason to waste the money on an isolator. Just keep the big 3 intact and run the wire from one battery to the other.

 

[c_b_ 10+ year member]

How do you figure this?

when the vehicle is off, the batteries will take turns charging and discharging each other, this endless cycle will cause premature failure.

 

[SPL Blazer 10+ year member]

when the vehicle is off, the batteries will take turns charging and discharging each other, this endless cycle will cause premature failure.

I can almost see what your saying, but your wrong. The batteries will discharge themselves at the same time if wired together, which is what he's talking about. They won't take turns discharging and recharging, they will discharge at the same time. And if it's off they won't be able to recharge. Alternators don't work without the vehicle running.

 

[plugitin 5,000+ posts]

If one battery is weaker then the other this might happen...but as long as the batts are decent and wired together, your good to go. Have done it many times without an isolator...