Dual battery systems for winching

[big bundy]

after dual batt's for winching, is there only one real type of dual battery system, ie charges up, 1st battery, once reached 13?? or so volts its charges the other one? but from what i have heard, when winching this doesn't allow current back through from the other batt fast enough?

plan to be using a yellow top as main batt and a 660cca as backup.

Anybody point me in the right direction???

[MUD EMPIRE]

At risk of being told I'm wrong.......My 2 cents.......
Use two batteries of the same type/make and wire
them together to give you 12V. Forget the wiring
systems involving high tec crap. Keep it simple.
This way your winch works well and it starts well
and the end user is happy......simple.

[DamTriton]

At risk of being told I'm wrong.......My 2 cents.......
Use two batteries of the same type/make and wire
them together to give you 12V. Forget the wiring
systems involving high tec crap. Keep it simple.
This way your winch works well and it starts well
and the end user is happy......simple.

K.I.S.S. principle....agree.

[ausyota]

Or just use one of those big rotary marine switches and leave them linked all the time except when you camp for the night and just isolate the starting bat.
That is the system I plan on using when I eventually set mine up.
I think this requires the two batteries to be identical to work well though.

[chimpboy]

At risk of being told I'm wrong.......My 2 cents.......
Use two batteries of the same type/make and wire
them together to give you 12V. Forget the wiring
systems involving high tec crap. Keep it simple.
This way your winch works well and it starts well
and the end user is happy......simple.

You're wrong

No, look, this is a good idea for some uses, but it is not actually a dual battery system in any meaningful sense. The idea of a dual battery system is that it keeps one battery protected from being drained, so you can always start the vehicle. With a simple setup where they are just wired together, you have no guarantee that you will be able to turn the starter motor after you've done your winching.

For a winching setup, you need to ask yourself what you want to achieve. Do you just want maximum winching, and don't care if you can start the car afterwards and/or you destroy batteries at a rapid rate? If so, no problem - hook them together directly and there's no better option.

But if you want to protect your ability to start, you need something more complex. The flipside of this however is that all the charge you are saving for starting is not available during winching.

Off the shelf automatic dual battery systems are all designed for camping/deep cycle type applications. They assume that the main drain will be on the aux. battery, and starting will be on the original battery. This is not optimal for a winching setup because for max winching, you run the winch off the same battery as the starter (since it is hooked to the alternator).

Anyway, to cut a long story short - what do you want from your dual battery system? Max winching at all costs? Security when it comes to starting? It makes a difference.

[chimpboy]

Or just use one of those big rotary marine switches and leave them linked all the time except when you camp for the night and just isolate the starting bat.
That is the system I plan on using when I eventually set mine up.
I think this requires the two batteries to be identical to work well though.

The batteries need to be identical for a 24V system. In a 12V system, ie batteries in parallel, it is probably better to make them identical but in reality, it really doesn't matter very much.

I can't say a big and costly marine rotary switch appeals to me much, a VSR type dual battery unit is only a hundred bucks and it's a setup and forget deal. What do the switches cost? I thought they were up near the same price, and they are much much crapper for the sort of camping application you have in mind.

[mudmacaca]

I would use a marine switch because it is easy and you are not relying on an electronic solenoid they handle a huge amount of amps and put up with some punishment and I dont think they are as expensive as you think.

I just got my hands on a 120ah deep cycle battery from a fire panel. I reckon I will have a hard time killing it

[chimpboy]

I would use a marine switch because it is easy and you are not relying on an electronic solenoid they handle a huge amount of amps and put up with some punishment and I dont think they are as expensive as you think.

I just got my hands on a 120ah deep cycle battery from a fire panel. I reckon I will have a hard time killing it

Fair enough, I thought they were around seventy bucks but now you mention it, they are only about twenty. So in that case, I agree, if you are trying to save the extra dollars it's a good option.

However, for what it's worth, I would trust a relay to be about as likely to break as a switch anyway.

[MitchellBros4x4]

I agreee with ausyota, go for the BEP marine grade Voltage Sensitive Relay setup. These days you get what you pay for and in my experience when you skimp on the cash to save it, you end up spending double that to fix it later. The BEP VSR will do everything you want it to do (doesnt make coffee or grab the phone when your under your truck), but it will manage you batteries for you and keep them in top notch condition, ready for when you need them most. I would recommend the 300amp unit which is the constant current draw that this unit will cope with, also, if you need some more oompf, you can switch it and use both batteries at once for winching, cold starting etc and it automatically switches after back after 10 seconds. The unit is very simple to install and can be done with simple hand tools.

[big bundy]

thanks heaps!