Dual battery settup

[muddyperils]

Been looking around for a while trying to decide the appropriate charging system for my needs, and I am now more confused than when I started???
I will be using the setup for winching and running a fridge!! Some people say duel cranking batteries are the go, others crank/deep cycle.....be buggered!!
One electrician doesn't like the traditional solinoid setup, that charges after the main battery has reached a certain charge, because what if it doesnt reach that charge due to some reason, the second will not get charged at all!!
So I am looking at a system that charges both batteries all the time....is this wise....any experiences would be great to here...

lord giveth me tha power

[chimpboy]

The idea behind the 'traditional' system is that if you have some kind of system failure, you can live without your second battery, which runs accessories, but you can't live without the main battery, which starts the car.

In other words, the logic is that you never want to be in a position where you can't start the engine. For example, if you have to do some heavy winching, you still want to be able to start the car afterwards. If you just leave the batteries permanently connected, you could drain them both when winching and you'd be farked next time you wanted to start the car. Remember you need that engine running to charge the battery after winching!

Normally, the second battery will start charging as soon as the first battery has been charged up from the work it did starting the car, which doesn't take long.

If you're really worried about the second battery not getting charged, you just want to have a little system for monitoring what the charging system is doing and/or the condition of the second battery. This is easy and cheap.

As for which type of battery to get, the ideal would be to have one for winching and one for the fridge, but in the real world three batteries take up a lot of space. There are some batteries, especially marine batteries, that are designed to do both (because it's more common on boats to use a single battery for starting and for accessories). I think one of the Optima Blue Top batteries is designed for this, or see the exide "stowaway" on this page.

I've never tried any of these batteries so I can't recommend one over the other.

If you can't get one that is designed for both cranking (ie winch) and deep cycling (ie fridge), then you would probably want to go for one that is designed for cranking. One that is purely for deep cycle will be too easy to kill with the winch, and will struggle to deliver good current to the winch anyway.

Cheers,

Jason

[Charlie]

You defiantly need a deep cycle for the fridge and the biggest cranking battery you can get for starting/winching preferably an optima yellow top which will accept as much charge as your alternator will give out as well as being duel cranking/deep cycle .I have a GSL battery isolator and wiring set up so I can jumper start from the deep cycle if the starter flattened by winching. Either way get the biggest batteries you can afford or fit.
Regards Charlie

[Kelvin Warburton]

You defiantly need a deep cycle for the fridge and the biggest cranking battery you can get for starting/winching preferably an optima yellow top which will accept as much charge as your alternator will give out as well as being duel cranking/deep cycle .I have a GSL battery isolator and wiring set up so I can jumper start from the deep cycle if the starter flattened by winching. Either way get the biggest batteries you can afford or fit.
Regards Charlie

[Tiny]

there is two trains of thought about he use of deep cycle batterines in a traditional 4wd dual battery set up. many old hats prefer the dual battery as it made for low amp draw for a long / constant period. The problem however with a deep cycle battery is the time it takes to charge, and in the life of most 4wdrivers it will struggle to charge in the required time. In a caravan the battery will have a solar cell ofr similar and will trickle charge at all time where as in a 4wd, unless you are going to drive all day flat out you will never keep up. A standard cranking or a marine battery which is a cross between cranking and deep cycle is beter as it will charge within the time the vehicle is running and wil well and truly last the time you are camping to run the fridge and the lights etc for the night.

Another benifit is running a winch of this secon cranking battery.

As far as soloniods go, you can get all kinds of battery control regulators etc, IMO as long as the 2 batteries are isolated from each other, and only charge when the main one is fully charged is all that is required. As said above you need to ensure that the main starting battery is preserved as you can live without cold beer, but you need to be able to start the car

[BOB_1]

I have had a different setup that has never failed me on the two cars ive had in the last 6 years. I run a winch, fridge, lights etc. Basically a 100 amp continuous duty solinoid connecting the two active terminals of two cranking batterys. When the ignition is on, the batterys are connected, when off, they are not. A small push button is used to click the solinoid if the main battery is too low to do it. All accessorys, winch, fridge, everything - is connected to the normal ignition battery (Starting battery) and nothing is connected to the other. I went this way after running a fridge off the second battery and having the accessories on running the stereo causing two flat batteries. Takes the point out of having them really. We run the "smart" soliniods in our work cruisers with our radios running off one and the starting off the other, the only smart thing about this setup is carrying a portable radio when both are flat.

Each to thier own depending on the use, the setup above was the simplest, cheapest, easiest and most reliable other than just running a cable between the two I have found.

[Charlie]

Good advice from Tiny but I'm always very wary of the term marine battery,you really need to do your research because their more to a marine battery than adding a blue top and fifty bucks to the price! The best guide thiers not a lot in the way of real bargins about in the battery world.
Regards Charlie

[Tiny]

Good advice from Tiny but I'm always very wary of the term marine battery,you really need to do your research because their more to a marine battery than adding a blue top and fifty bucks to the price! The best guide thiers not a lot in the way of real bargins about in the battery world.
Regards Charlie

as always a good reputable brand is the way to go and in this case a marine battery is engineered differently. They are probably over priced any way as it is considered a specialty item, but in reality there is no real difference in manafacuring costs.

An optima is idealy the best as they are engineered to cope with the bumpy ride a battery will get in a 4wd, but they are also worth a pretty penny so while the costs are worth it in the long run, the initial cost may well be beyond the budget allowed.

Optima are here http://www.my4x4.com.au/onlinestore/sto ... ategory=91 with pricing so you can see the kind of budget you need to go down this path.

As far as standard batteries the Century are a good option, they are not an optima, but they do handle the task very well.

Try to steer clear of the NRMA branded batteries, they tend to have a short life aspecially in hard conditions

[Nev62]

For the last 5 years I have not run a winch, I have no accessaries, do not do trips by myself to isolated locations and my engine is a 2.6lt 4cyl petrol. What battery do I run??? One $49.95 Kmart special for 5 years and never had a problem

[HotFourOk]

Thanks for that