Problem (I think) with Redarc Isolator

[baitfish]

with ur isolator mate what makes it switch on and off, is it a voltage sensing type or is it just an input? if its a sensing one then make sure its getting its reading only from the main battery, if its an input from an external source like ur acc switch, then tripping the CB wont cut power to the acc circuit and the isolator will remain on.

 

[maulbeagle]

OK, updated diagram with all breakers etc included.
Also wiring from aux battery going to tub and voltage gauge.
Tony can you see anything on here that would cause the isolator to misbehave ?
it's a Redarc, which I believe switches solely on the voltage of the battery connected to the "main" terminal.

 

[mitch92]

Ok, if your drivers side is to be your aux, but goes to the main terminal, then from that to cb then Passenger side I think the problem is in the driver batt. If the relay senses the voltage from this main terminal then if the cb trips there is still voltage above 13.2 on the driver battery, so relay will stay on till this drops off.

 

[Old.Tony]

The isolator shouldn't need to be between the aux battery and the back of the car, it should be between the two batteries only - there might be something happening from that.

I've redrawn how I'd wire it up, and I've NOT drawn in the negative lines, because they COULD all just go to chassis anyway, although the run to the rear benefits from being cabled individually, removing that half from the diagram makes it clearer.

Symbols should be fairly obvious. A = alternator, I = isolator, B = breaker. No real need for a breaker in the engine bay since your cable should be well-protected.

 

[bods]

From what you are saying the isolator is behaving normally. What happens if you apply load to the aux battery and get the voltage down a bit? Also, the redarc you have, does it have dual voltage sensing or just the main terminal?

 

[maulbeagle]

bods, i'm not sure. will try this and get back to you.
also not sure if it's dual sensing, it's just an SBI12.

 

[baitfish]

old tony's on the money i reckon mate, you've gone a bit over the top really. Bods has a point to, if you trip your CB the red arc wont switch until whatever battery it is sensing drops to low and starts drawing from the other battery to level themselves out.

I'd leave the CB or isolator in there just encase you want to remove the AUX for some reason, that way you can positive isolate the AUX battery terminal and not have it arc out on anything.

 

[sparra04]

Any updates?

 

[maulbeagle]

no updates yet Sparra.
only thing that makes sense to me is that the isolator is dual sensing, but i don't know how to tell the difference between the standard and dual ones.

 

[baitfish]

just an idea mate, when u open the CB, and put your meter on each battery when the ute is running, which one has 13.8 or so and which one has the same voltage as when the car is off?

 

[maulbeagle]

i think that they both will have 13.8 as the isolator doesn't disengage when I open the circuit breaker.
will give it a go though.

 

[baitfish]

by your drawing there should be no path from the CB to the isolator when the CB is open, so whether or not the isolator opens the batteries should be isolated from each other. One should have the alternator voltage, the other just battery voltage. Have you tired disconnecting both sides of the isolator and checking with ohms if if actually operates?

 

[maulbeagle]

OK will check it and see.
haven't tested the isolator with nothing connected, as i know it definitely isolates the batteries when the starting battery is not fully charged (eg after starting the car), and then joins them once the battery is charged.

 

[baitfish]

is this how yours is set up?

 

[maulbeagle]

effectively it looks the same (mine has more doo-dads hanging off it).

 

[maulbeagle]

@baitfish -

by your drawing there should be no path from the CB to the isolator when the CB is open, so whether or not the isolator opens the batteries should be isolated from each other. One should have the alternator voltage, the other just battery voltage.

ok so did the test, with the car running and the circuit breaker open, the starting battery (passenger side) is at 14.16 volts, the aux battery (drivers side) is at 13.2, the same as without the car running.
during this whole test the isolator stayed engaged (lit up, terminals joined).

i'm thinking maybe faulty isolator ? according to the pictures from redarc it definitely isn't a dual sensing model, as mine has the override wire which the dual doesn't appear to have.

 

[bods]

Can you put up a pic of your setup? What happens if you engage the override wire? Does the voltage even out between batteries? Can you hear the solenoid click when it engages?

 

[maulbeagle]

bods there was some pics on earlier posts.
the isolator definitely clicks, lights up, and engages properly, the issues seems to be it doesn't disengage (isolate batteries) when the circuit breaker between the starting battery and the "main" terminal of the isolator is opened.

 

[Old.Tony]

If there's no change in the aux battery then the alternator's having no influence on it. We need to test some more.

Without starting the car, load the auxiliary battery up for a while with a decent load. You want the battery voltage to drop to 12.4-12.6V which will NEED recharging.

Still without starting the car, disconnect the isolator's input from the starter battery (which should also disconnect it from the alternator).

Start the car and measure the voltages on both batteries.

If your aux battery is showing a higher voltage, then it's being powered from somewhere else - it's not right, because it means the aux battery could drain the starter. This could also be throwing off the voltage measurements making the isolator look like it's not working properly. This test will determine whether or not that's what is happening.

 

[bods]

I've seen the diagrams, I meant actual photos of the way it looks in the vehicle to see if there's anything that doesn't quite look right...