what do battery isolators do

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=102542
Printed Date: May 04, 2024 at 3:12 AM

Topic: what do battery isolators do

Posted By: memphisgod
Subject: what do battery isolators do
Date Posted: February 25, 2008 at 3:14 PM

I am curious what exactly a battery isolator does. I can get them really cheep and I think I might need one but i need to know what they do first.

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Memphis Gods Need Some Mojo

Replies:

Posted By: KPierson
Date Posted: February 25, 2008 at 3:48 PM

The point of an isolator is two fold.

1. it prevents your alternator from seeing two batteries at the same time. A battery is a load, and usually adding a second battery to a charging system will stress the alternator.

2. Prevents both batteries from being discharged. You can use your "reserve" battery for engine off listening and when it is dead your radio will shut off. However, when you go to start the car you will switch back to the "primary" battery and the car will start right up.

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Kevin Pierson

Posted By: Petebob
Date Posted: March 02, 2008 at 2:59 PM

Are these known by any other names? over here (UK) when I take a quick look on eBay they only have the large red key swtich.

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The Original Muppet

Posted By: mrrairai
Date Posted: March 03, 2008 at 8:51 AM

They are also known as solenoids.

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Kenwood XXV-05V
Clarion 7" Monitor
(4) T212D2
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(1) RF Power 750X
(2) T162S Components
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(2) Powermaster D3100s

Posted By: Petebob
Date Posted: March 04, 2008 at 12:34 PM

When you say "Solenoid" isn't that a general sort of term for an electrical coil device?

If any of you guys could point out a kit on the web, I'd appreciate it.

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The Original Muppet

Posted By: toofly
Date Posted: March 14, 2008 at 11:28 AM

you could try and look up battery isolators

Posted By: superchuckles
Date Posted: April 02, 2008 at 4:08 AM

actually, most battery "isolators" are just a bunch of diodes wired up in parallel to increase their current flow, hooked up between the alternator & batteries, so that your vehicle can have separate batteries for the audio system (or whatever) and the starting system. the "isolation" happens because the diodes prevent the audio battery from draining the starting battery, yet allow the single alternator to charge both batteries. pretty simple actually.

Posted By: superchuckles
Date Posted: April 02, 2008 at 4:10 AM

what you guys are thinking about with "solenoids" & key switches are battery disconnects. they are used to quickly disconnect the battery from the system in case of short, or if you just need to do it over & over & don't want to have to unbolt a battery cable.