Battery isolator issue

Quote:

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Originally Posted by irondoc

Thanks Tim, I'll try tomorrow.

I seem to remember that when i reverse polarity, it reads -12.6V, not the small amount you suggest.
Cheers
Lucas

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Hi Lucas, if the instructions in my last post seem double-dutch to you, phone me when you can carry out some tests and I will talk you through the testing.

OK, I think I have solved my problem - sort-of. Thanks for the advice Tim.

When I do your earth test, I get a voltage of 1.5mV or thereabouts, so less than the 0.02V you mentioned.

I took all my measurements from the battery terminals as well as my ABR battery monitor for the tests. The auxillary battery was at 12.7V and the main battery 12.55 when I started and the batteries were separated.

When I started the fridge, the auxillary battery dropped to 12.2V on the ABR monitor, but read 12.4V at the terminals. The main battery dropped to 12.35V on the ABR monitor, but maintained 12.55V at the terminals.

So it seems the issue is with the battery monitor - the main battery is not providing current to the fridge, it just seems the battery monitor is getting affected by something - possibly because the fridge and battery monitor are earthed at the same point..... But I guess I am happy that the batteries are truly separated.

Thanks again
Lucas

Hi guys, just to clarify my minor electrical gremlins, I think I discovered something else which made me feel something wasn't quite right with my battery voltages.

I also had the sense that something was still drawing power when the car was off - well, I think I found it - I have the console cooler and I noticed yesterday that the cooler was switched on. It runs for a few minutes after the car is stopped, and I suspect this was responsible for the lower main battery voltages as well as the Redarc isolator disconnecting early, when it used to stay connected for a longer period.

Well, I hope that is it and will solve my issues.
Cheers
Lucas