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duel batteries and how they work ?
Posted: Wed Sep 28, 2005 1:19 am
by Mousie
hi i have all the gear already in the gar i just got but.. how the hell dose it all work ?
it states on the solenoid cut in 13.8 cut out 12.7
so dose that mean while the voltage is above 12.7 it will be used and charged
once drops bellow 12.7 dosnt get used or charged ?
is this true ? dose the alternator charge thet batterie at all or do u have to pull it out arfter it reaches 12.7 and recharge it ?
thanks
Re: duel batteries and how they work ?
Posted: Wed Sep 28, 2005 8:52 am
by chimpboy
Mousie wrote:hi i have all the gear already in the gar i just got but.. how the hell dose it all work ?
it states on the solenoid cut in 13.8 cut out 12.7
so dose that mean while the voltage is above 12.7 it will be used and charged
once drops bellow 12.7 dosnt get used or charged ?
is this true ? dose the alternator charge thet batterie at all or do u have to pull it out arfter it reaches 12.7 and recharge it ?
thanks
Not exactly. It means that when your main system (alternator plus original battery) has more than 13.8V, the solenoid will kick in so that your main system starts charging battery number two.
Then when the voltage drops below 12.7V, either because of some serious drain eg a winch, or because the engine has been switched off, the solenoid will disengage and isolate battery #2. That means you can drain battery #2 as much as you like and battery #1 will stay charged so you can start the car.
So the usual scenario would be:
Battery #2 has been drained by your fridge (or whatever).
Battery #1 is fully charged. You start the car, draining battery #1 a bit.
Engine running, alternator charges up #1 only, until it's so fully charged that voltage hits 13.8V.
Solenoid senses voltage and kicks in, so battery #2 starts charging using alternator current plus battery #1.
You shut down the car, solenoid disengages so that battery #2 (or anything hooked up to it) can't drain battery #1.
In other words, the system is designed to always charge your starting battery first, and only start charging your aux battery when the starting battery is fully charged. So the purpose of the system is not so much to give you the super power of two batteries, it is to protect one battery for starting while you use the other battery for other stuff.
Jason
Posted: Wed Sep 28, 2005 11:53 am
by mabsydney
Duel batteries fight each other with pistols at dawn.
Dual batteries on the other hand are used in your 4wd to power accessories without flattening your cranking battery

Posted: Wed Sep 28, 2005 3:06 pm
by Mousie
ahhhh ok nice i see i see
now i just gotta get a second batterie
Posted: Sat Oct 01, 2005 6:24 pm
by vanzbrown
Sorry, just on this, is it worth getting one of the Duel Battery Kits that some of the 4wd store market, or just get one set up at the local auto electrician. I remember reading somewhere that someone bought a solinoid from Dick smith or someplace and hooked up a duel battery set up them selves. With the solinoid setup, deep cycle or normal for the second battery if you dont have an electric winch?
Thanks
Lee.
PS. Sorry to hijack, but i figure its roughly on topic...
Posted: Sun Oct 02, 2005 9:42 am
by G_loomis
I have a dual battery isolator that I am goin to fit to my truck...It only has 3 wires coming from it.
RED : 12V positive main battery
BLACK : Negative earth
WHITE : 12V Positive Aux. Battery
In the diagram that came with the isolator it has a circuit breaker in between the isolator and battery on the red wire. What sort of circuit breaker is this meant to be? And where can I get them from?
There is also a V. Booster (which is optional) on the white wire between the isolator and Aux. Battery. I am guessing this is a Voltage booster

Would there be any benefit to having this in my setup?
I am in the south brisbane area if that helps!
Posted: Mon Oct 03, 2005 9:10 am
by Shadow
G_loomis wrote:I have a dual battery isolator that I am goin to fit to my truck...It only has 3 wires coming from it.
RED : 12V positive main battery
BLACK : Negative earth
WHITE : 12V Positive Aux. Battery
In the diagram that came with the isolator it has a circuit breaker in between the isolator and battery on the red wire. What sort of circuit breaker is this meant to be? And where can I get them from?
There is also a V. Booster (which is optional) on the white wire between the isolator and Aux. Battery. I am guessing this is a Voltage booster

Would there be any benefit to having this in my setup?
I am in the south brisbane area if that helps!
A circuit breaker can be purchased from any auto electrics places. They sell them for car audio applications aswell so any big ricer stores will carry them.(probably at an inflates cost though) Normally they are self resetting, but you can get manual resetting breakers asell.
You can get them fairly easily up to about 200amp, I would suggest at least a 100amp breaker for a battery charging application.