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May 12, 2009 | 03:30 AM

SPL FREEK

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From: NEW YORK

isolators

I've been wondering of how many of you guys are running dual batteries?
and also...why do some of you guys run isolators and some of you don't?

May 12, 2009 | 05:19 AM

Papajorgio

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From: hawaii&florida

http://ezinearticles.com/?Battery-Is...tems&id=683228

hope this helps..

May 12, 2009 | 07:56 AM

mkorsu

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From: East Bumble F, NJ

For multiple battery installs at my shop we build battery isolation circuits using 200amp relays. The main reason is to allow the alternator to charge all batteries in the system while the engine is running but seperate the front "main" battery from the systems battery(s). This way, if the customer plays the system at a show with the car off and drains the rear battery(s), he can still switch to the front battery and start his car.

Additionally, a battery isolator has a .7 volt drop at each isolator (standard voltage drop for a diode), so we use relays to avoid the voltage drop.

May 13, 2009 | 09:09 AM

Big Mack

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From: Arizona

Quote:

Originally Posted by sueno2jz

http://ezinearticles.com/?Battery-Is...tems&id=683228

hope this helps..

Wow..."Most people run their amplifiers and added accessories from a secondary amp to lighten the load on other factory installed devices."

Really? I would think most people would run them from a secondary battery, and it doesn't lighten the load on other factory installed devices at all. It actually adds to the load presented to the alternator.

Isolators are good - provided you use solenoid based ones (the article actually did a decent job explaining this). Standard voltage drop across a silicon diode is 0.6V - not a tremendous amount when you consider the alt should ideally be charging at 14.4V. Batteries are 13.8V, and there you have a difference of 0.6V. Since most alternators charge up a bit higher than that, though, their potential is still higher than the battery, therefore current will flow.

Let's be clear, though - batteries are only good for additional engine off time for accessories. If you are trying to feed more amplifiers or other equipment but exceed the capabilities of the alternator, you're not going to see a benefit until you add an alternator that keeps up.

Big Mack

May 31, 2009 | 02:38 PM

SPL FREEK

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From: NEW YORK

I mean i have a stinger relay isolator but i have seen people just slice off the alternator wire and go direct. I mean.. Is that safe??????????

May 31, 2009 | 03:31 PM

Big Mack

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From: Arizona

Quote:

Originally Posted by SPL FREEK

I mean i have a stinger relay isolator but i have seen people just slice off the alternator wire and go direct. I mean.. Is that safe??????????

Safe for what? Starting fires? If so, then yes. If not, then no. There should be a fuse inline, at a bare minimum. Most sanctioning bodies won't let you run directly to an alternator from what I remember, but it's been a while. If you're talking extreme competitors, though, they'll do pretty much anything, including blowing up amps and subs just to squeeze out an extra 0.1 dB, so don't gauge it on that. For a regular use vehicle, go with an upgraded setup that has all the standard parts inline.

Big Mack