# Isolator?



## NissanTuner (Dec 1, 2002)

Whats the purpose of a battery isolator? I have 2 batterries hooked up in parallel w/o an isolator, and I havent had any problems in the 5-6 months they've been hooked up that way? I hear a lot of people say on the boards you should buy an isolator if you hook batteries up in parallel, what exactly is the purpose?


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## Nostrodomas (Jun 15, 2002)

WHY YOU NEED TO ISOLATE YOUR BATTERIES 
Many vehicles and other types of equipment have multiple batteries... one to start the engine, and others to power accessories. To understand the problem of multi-battery drain, and how a Power Battery Isolator prevents it, think of electricity as water. Electrical current is equal to the flow of water, and voltage is equal to the pressure. The alternator pumps current (water) into the batteries. 

The current then flows through the wires (pipes) to the accessories. Its important to think of batteries as storage tanks. If a fully charged battery is connected directly parallel with a discharged or empty battery, the voltage pressure in the full battery will force its current into the empty battery until the current stored in both batteries reaches a common level. The discharged battery will always rob power from a charged battery. So, no matter how many batteries you have on your vehicle, the accessories connected to one will draw power from the other batteries in the circuit. This is the problem of multi-battery drain. If it's allowed to continue unchecked, it can leave you stuck with dead batteries and an engine that won't start... all when you least expect it. 

THE SOLUTION 
To eliminate the multi-battery drain problem, a Power Isolator acts as a check valve between the batteries, preventing current from flowing from one battery to another. Each battery is isolated, and acts as an independent power source. So, no matter how drained your accessory batteries become, they will never drain power from the battery you are depending on to start your engine. When the current is used from battery #2, the check valve (diodes) stops current flow from battery #1. When the alternator is charging, current can only flow in one direction, from the alternator to the batteries. 

Each battery then determines the amount of current which flows into it by its own state of charge based on the voltage regulator setting. With this system, the alternator is protected, and the batteries are protected. The balanced electronic Isolator is absolutely the only way proper isolation and control can be accomplished and every multi-battery problem solved.


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## kbrassfi (Aug 1, 2002)

what they are probably referring to is not just an isolator, but an isolator/relay, works the same way as an isolator but swithes between batteries to try to charge them, but if you add too much power your stock alternator can't hold a charge on one battery much less two. Best bet? upgrade your alternator and screw the second battery, its useless pretty much. because it doesn't matter how much storage capacity you have if you can't refill them at the same or higher rate than they are depleting themselves


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## NissanTuner (Dec 1, 2002)

ok thats kinda what i thought an isolator was used for, o prvent a battery from draining another battery.

On a side note though, I have yet to deplete either of my batteries, i think people underestimate the amount of power the alternator can put back into the battery when its in use.

Some nights I go out and have both the 1350 watt system running at about 50% of max volume, and an 800 watt power inverter running for 5+ hours straight. I can run the both for about 2 hours before i notice my lights start to flicker while im parked, if im driving i never get flicker.

I want another alternator, but only because im pretty sure this one will burn out eventually. a larger alternator wont let me run my system for longer if im parked.

Thanks guys, Heath that was a pretty intuitive explanation


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## kbrassfi (Aug 1, 2002)

actually I have ran my system on stock alternator with a meter hooked up to it, even runnin with 0 guage wire to the back it was only putting out less than 12 volts, you are not getting optimum performance from your system if not running at 14.4V which is what most amps, etc rate their power ratings at, if you still think you know whats going on, go for it, more power to you, but I've been down this road and I think I have a little more experience with it. I would say at the very minimum you'll need a isolator/relay to be on the safe side.


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## NissanTuner (Dec 1, 2002)

Not sayin I know more about audio than you, i plan on buying an isolator just to be on the safe side, and I would still like to upgrade my alternator, but thats kinda pricey in light of all the other upgrades im going thorugh right now.

Thanks for the info guys


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