Dual Battery Wiring diagram?

[CJ Burns Esq]

Does any one have a diagram for wiring up a Dual battery set up?
Any help appreciated.
CJ

[Area54]

What is your planned purpose for the batteries - there are quite a few ways to wire up two batteries.

Planned usage: Winching or fridge/accessories?
This will be your first question, once you know this then you can plan which batteries (deep cycle or regular cranking) to buy, and at the same time work out which system.

[CJ Burns Esq]

"D" All of the above.
I don't yet have a winch but it is definitely on the cards due to the type of places I go to and the unsavoury people I know.
I am looking at options at the moment.
What would you suggest if I was going for a winch set up?

[BeZeRK]

use a normal solinoid, $40

one side to main batt, other to second batt, the small terminal on solinoid that is on main batt side goes to earth, other small terminal goes to somthing that turns on with ignition (ie Wiper motor)

Easy as that, if you want more control, put a switch on the wire going to wiper motor, so you can use the switch to turn system on or off....

Very simple system, but it works

[BeZeRK]

Oh, yea, and for the second, use a deep cycle battery, run all your accessories off this.. Your main battery should only run starter and winch.

[Area54]

Ahh, not a good idea to use two different types of batteries in this system. This system is good, but a deep cycle battery is no good for cranking (they aren't designed for this purpose, this shortens the life of the battery considerably). With this system the batteries are connected when cranking and when in the 'accessory' position (ignition). The batteries need to be separated for use (pirahna make an excellent dual battery system) if you want to incorporate a deep cycle. How much winching do you intend to do? how long do you want to run the fridge? I can't offer detailed info on the winching, but I can help you with the fridge etc.
Depending on the vehicle, it would also pay to upgrade the current output of the alternator to cope with added charging load of two batteries.

[Andrew_C]

With the solinoid system, put a wire running from the + extra battery through a button on the dash to the solinoid also so if your main battery is so drained it can't run the solinoid. just press the button and away you go. No more need to carry jumper leads. Not like mr piranah's setup when you still need jumper leads to start it with a flat battery from one to the other.(Don't get me started on piranahs crappy rip off systems.)

[landy_man]

the pirhana systems are very good at what they do and are designed for... that is to run many low drain accessories off a deep cycle battery...
I had one in my defender and it never gave any trouble... even after filling the battery box (under the seat - what was LR thinking) many times with beautiful thick Toolangi mud slush

a mate runs the jaycar DIY kit in his Rangie and as far as I know never had a problem...
if you're handy with a soldering iron and know your way around capacitors and resistors this kit at $60 or something is a bargain...

[BundyRumandCoke]

If you go for the solinoid connected to your ignition system( which I have in mine and has given me no troubles) get a continuious duty solinoid, not an intermittant duty, such as a starter one. Intermittant duty ones are just that, for intermittant use only, and they wont handle being on continuiously.

[murcod]

a mate runs the jaycar DIY kit in his Rangie and as far as I know never had a problem...
if you're handy with a soldering iron and know your way around capacitors and resistors this kit at $60 or something is a bargain...

I've got the Jaycar/ Dick Smith kit in my Feroza. It suits my purposes well and I haven't had any problems with it.

The only negative thing I've discovered about it is, while it won't drain your main battery, if your main goes flat it could drain your auxilary. There are diodes in the MOSFETs that it uses to isolate the batteries and they will conduct back into the main battery: eg. I disconnected the earth on my main battery only to discover everything still had power to it because the controller was allowing the aux to supply power back to the main and the aux battery was earthed separately.

It's therefore feasible that if the main battery had a problem and was flat enough the auxilary could discharged into it... or put another way, leave your headlights on and both batteries can go flat.