standard battery isolator in a tahoe

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=98117
Printed Date: May 16, 2024 at 9:50 PM

Topic: standard battery isolator in a tahoe

Posted By: hardwarz
Subject: standard battery isolator in a tahoe
Date Posted: October 19, 2007 at 2:18 PM

I purchased a battery isolator from Summit Racing last winter. I mounted it to my 99 Tahoe, but never got a chance to hook it up. I finally hooked it up and it doesn't work.

I researched it and it's a standard battery isolator. Apparently, I need a CS battery isolator designed for a GM. The CS type battery isolator has an extra input for the ignition. ???

When I apply 12-14VDC to the center, I get 12-14VDC -0.7VDC at each terminal. When I hook the isolator up to the alternator, it sees ZERO voltage at the center terminal.

Can someone explain why the 4th terminal for the ignition is on the CS battery isolator. Can someone help me hook this standard battery isolator up so it'll work or am I screwed and have to sell it and buy a CS type battery isolator?

The isolator I have is a Transpo 140A. It's installed in a 1999 (old body style) Chevy Tahoe, Vortech 350, 4x4, 4 door with tow package.

Thanks

Hardwarz

Replies:

Posted By: fakepete
Date Posted: October 19, 2007 at 2:40 PM

I was unable to find any information about this isolator. Did it come with any diagrams or terminal markings?

From the results of your testing, I would guess that the alternator would be connected to the center terminal and the battery would connect to either of the other two terminals. The unused terminal could be connected to a second battery if you have/need one.

Posted By: audiocableguy
Date Posted: October 19, 2007 at 3:03 PM

You can use a 300Amp Contactor Switch (big 12V relay) to isolate your batteries. Stinger and others use the same unit, they just re-brand it.
Voltage drop across the isolation diodes is a loss between half and a full volt.

Posted By: hardwarz
Date Posted: October 19, 2007 at 3:51 PM

fakepete wrote:

I was unable to find any information about this isolator. Did it come with any diagrams or terminal markings?

From the results of your testing, I would guess that the alternator would be connected to the center terminal and the battery would connect to either of the other two terminals. The unused terminal could be connected to a second battery if you have/need one.

https://www.transpo-usa.com/ That's the company (at least that's the logo on the isolator and the name)

https://www.motorcityreman.com/2-130.html sells the Transpo 130 standard battery isolator

posted_image

Here'ss a image of a standard install.

posted_image

A standard isolator would hook up just as described. I've now found CS type isolators

posted_image

I'm just trying to find out if there's a way to use the std battery isolator in a GM.

Hardwarz

Posted By: fakepete
Date Posted: October 19, 2007 at 5:59 PM

I didn't realize your alt needed the excitation and voltage regulation wiring to operate. I would go with audiocableguy's suggestion and use a contactor or solenoid switch.

And just out of curiosity, why do you need an isolator?

Posted By: hardwarz
Date Posted: October 19, 2007 at 9:16 PM

I'm hooking the isolator up so that:

1) I can charge both batteries.

2) Using a Ford type starter relay, use the 2nd battery to jump start the Tahoe from inside the cab without getting out of the vehicle. (Relay will get it's +12VDC from the 2nd battery and ground out inside the cab) I wanted to do this last winter, but the isolator didn't workout the way I wanted it to.

3) The stereo system I'm building will get it's +12VDC from this battery, as well as the new lights (fog and maybe overhead spots)

Thanks for all the help.

Hardwarz

Posted By: audiocableguy
Date Posted: October 19, 2007 at 9:48 PM

https://www.wranglernw.com/pc-6348-790-dual-battery-tray-kit-for-chevrolet-suburban-tahoegmc-yukon-ck-pickup-1996-1999.aspx

Posted By: hardwarz
Date Posted: October 19, 2007 at 11:17 PM

Humm... picked up the stock tray from my dealer for $35. Wire, I took from a pair of heavy duty jumper cables (4g), $25. Ford type Starter Solenoids, $30.

Got everything except that neat little switch. The switch has, Dual on, Dual Off and Emergency on. Seems to me that Dual On and Emergency On are the same thing, especially since it's only dual battery and single solenoid. (now 3 batteries, that would be more imaginative.

Maybe I should look at doing something like, a 30A relay that feeds it's self to activate the starter solenoid. When the engine shuts down, the power will be interrupted and dual batteries are off. With engine on, press the button and it charges the 2nd battery (or jumps the other battery)

Thanks for everything.

Hardwarz