VE Ex Police Duel Batteries

[Garfish58]

I have just purchased an ex police car which has duel batteries, does anyone know whether you can switch between the two?

[Grinded]

Is there a reason to switch between the two?

I would think if its setup like most others it was most likely there to run all their extra bits (2 ways, lights etc etc.)

No expert on this but I do know that a mates cruiser has dual batteries, and the backup one trickle charges the primary battery, and has never had the primary battery go flat on him since installing it around 3 years ago.

[vlctrazz]

no u cant switch between the 2, it is just there to power the lights and radios, if you havent connected anything to it, it wont be doing a thing.

[BOOGER]

as above said, you can't switch between the 2. We were having quite a few problems with ours going flat. Holden put an isolator switch in so we could switch between them ie use one battery, charge the other then switch over.

[APCLB]

Perfect for a BIG sound system setup.......

[Garfish58]

Hi Guys

Thanks for the all your feed back, much appreciated.

[Dillzio]

sorry to revive and old thread like this, but i figure it's better than starting a new one on the exact same topic.

I've just found a second battery in my ex police VE (from SA) and I was wondering if it's doing anything at all. It has lots of wires and plugs coming off of it and looks like it used to have the lights, siren, computer, doughnut maker etc hooked up to it.

When I turn on headlights/highbeams with the key out (should run off accessory battery if it's set to) the voltage drops on the main battery but not the second/accessory battery. Likewise, when I start the car, the voltage goes up on the main battery, but not on the second battery. I'm wondering if the second battery is hooked up at all?

The second battery just sits on 12.95v whatever I seem to do to it. One thing I was thinking though is that perhaps the accessory battery won't be set to charge until it's voltage gets lower than it is. Does anyone have any experience with this setup and know how it works?

thanks

[XUV]

wack one of these SMART START SBI 12V 100A (SBI12) in it and at the flick of a switch have the other battery as a start up back up
http://www.redarc.com.au/products/uploaded/thumbnails/db_file_img_222_300x300.jpg

[Dillzio]

wack one of these SMART START SBI 12V 100A (SBI12) in it and at the flick of a switch have the other battery as a start up back up
http://www.redarc.com.au/products/uploaded/thumbnails/db_file_img_222_300x300.jpg

100A wouldn't be enough to start a car though would it?

I had another fiddle with the second battery today and found out it does have a isolator on it that clicks on after a while then the second battery starts charging. It didn't seem to do it yesterday, but after I charged the main battery overnight and put 7AH into it now the second battery is actually connecting to the alternator about 10 sec after I start the car - perhaps the accessory battery only starts charging when the primary battery is really full? It was reading about 14.3 with the car running yesterday which I would think would be enough for the isolator to click on but perhaps not.

I tested the resistance between the positive terminals of the two batteries and found they do seem to be hooked together once the isolator clicks on, all be it with about 3ohms resistance though. I also had a good look at the wiring and I still don't think the battery is actually powering anything. All the plugs for the cop gadgets are dead because they're hooked up to two relays with nothing connected to switch them on. There is a lead coming off the battery that leads to one of those self-resetting circuit breaker things that's about the size and shape of a matchbox (i forget their proper name), and there's a fairly hefty wire coming off that heading towards the front of the car behind the wall liner of the boot but I don't know what that's connected to (if anything).

I also noticed the second battery is a car starter battery (530CCA), not a deep cycle battery, but according to the service record it was replaced after the equipment was left on about 6 months ago so perhaps the roadside assist guy put in a normal battery instead - the second battery looks pretty much brand new!

[XUV]

100A wouldn't be enough to start a car though would it?
!
that's not what that means, it's how many amps coming your alternator, your alternator is 85 or 100amp.

Starting depends on battery cca and cable thickness.

Isolators generaly switch on when main battery is at 13.2 Volts to charge 2nd battery an switches off when main battery drops to 12.6 Volts

the redarc does this , but at the flick of a switch it form a link to the 2nd battery if main battery is flat.

You could disconnect the main battery and see if it starts as it mite have one in place,
as coppers wouldn't want to be stuck with a flat battery , just ask one of the many that come here ;)

[Dillzio]

I have my doubts the second batt could start the car as I don't think the leads connecting to it are thick enough, but I might give it a try and see what happens :)