oracle7

I'm planing to have a Parallel dual battery wiring . I have a good altanator that pushes 160 amp , I have optima yellow top. Now i need some guidance how to install both battery's.


I plan to do the fallowing . conect the second optima battery like a capasitor. for instance tha main baterry in engine second in trunk , so a positive wire will come from the main batt in engine to the second batt in trunk. Is this correct ? please let me know .

I heard about conecting solenoid/isolators bewen the 2 batteries, wich is more complicated/complex, but if if is ok to conect as i mentioned in the previous paragraph i will do it .

thanks for the imputs

oracle7

Ive read up that must use a solenoid/isolator to avoid "system drain " what system drain ?

Posible explanations :

system drain = drain the main battery + the aux baterry

system drain = each battery will suck power from each other (wich dosent make sense )


any other explanation about the " system drain " mystery word for not using a isolator/solenoid ???

MTT

iTrader: (17)

I installed my second battery in the trunk, ran a power wire from the alternator post to the battery in the back, grounded the rear battery, no isolator no nothing, still going strong as the day i installed it after two years.

note: both batteries are exactly the same and are the exact same age (this seemed important to whoever told me how to do it).

BigRedGuy

iTrader: (11)

In no particular order......

The "system drain" you're talking about is the result of running your stereo with the engine off in a 1 battery situation. This results in phone calls for boosts from all your friends.

An isolator is installed along with the second battery to prevent this. Any time you run the stereo with the engine off, the isolator prevents any draw on your "main" battery. Once the engine is running again, the alternator will charge up the second battery no problem.

MTT, the reason both batteries have to be the same model and age is to ensure they both charge and discharge at the same rate. It helps to stabilize the voltage levels and your alternator will thank you for it.

Personally I have always suggested an isolator in any multi-battery system my buddies have setup. I don't run my stereo with the engine off for more than a couple of minutes, so it hasn't been an issue for me.

HTH

oracle7

Thanks guys really appreciate the imputs.

KenC

The actual definition of a system drain in regards to isolating batteries is a result of the voltage drop. All voltages that are not isolated from each other try to equalize themselves out.

This means that if you're trying to play something off of a rear battery, it drains some of the voltage from that battery. Because of this, the front battery tries to equalize the difference, lending the rear battery some voltage. Because of the voltage loss due to wire length and such, the batteries can commonly just pitch voltage back and forth to each other when the vehicle is on, or when it is off, because it cannot always equalize perfectly.

Due to voltage loss in wires, if this keeps happening when a car's alternator is off, it can lead to the battery being drained through the resistance in the wire that connects the positive leads. An isolator prevents this by making the batteries effectively not 'see' each other, and therefore disables them from wasting voltage like this.