A few questions

[cad69]

For the amount of use the winch would get a 24v solar cell might be enough to trickle charge the 24v battery. Is there enough sun over there?

Cad

[FredTransit]

For the amount of use the winch would get a 24v solar cell might be enough to trickle charge the 24v battery. Is there enough sun over there?

Cad

You are, of course joking?

[cad69]

You are, of course joking?

What a shame, solar cells are widely used down here. Handy things on campers.

Cad.

[stevew]

Does anyone make such a switch... haven't come across it before. Tho it could be done with contactors but sooner or later you will get the big bang on a failure me thinks.

Cad

You can get big contactors, 100A+ rating, reasonably cheaply and they are really quite robust and unlikely to cause a problem. But that's what fuses are for!

It would be quite an easy job for any one with access to fat cable and a big crimping tool. I'd have no worries doing it.

Here's what I had in mind:


You'd just have to make sure that the AUX battery was NOT connected directly to the van body.

Steve

P.S. I've got small solar panel on my van but really it does **** all! Still it keeps the battery in good condition when I don't use the van for while.

[cad69]

Yep that looks like it would work. I would like to see an auxillary set of contacts cut the supply from the alternator on 24v mode, got a gut feeling it would blow the diode rectifier sooner or later, also like to see two contactors with pos and neg separated. Bit of dust and moisture.....

Looks good tho... well done.

Cad.

[sidspop]

That layout would work, but then you would need a very big alternator to recahrge the two batteries after use by the winch. They draw a hell of a current.
If I were doing this job, I would put two batteries in series close to the winch, and add a 24volt alternator to the engine. That way the 12 and 24 systems are isolated, and no large switched currents are needed.
Make sense?

[stevew]

You want to cut the alternator off because you think the winch would draw too much current? Hmmm, maybe. You could fit a breaker in place of the fuse. They're pretty cheap these days with all the multi kilowatt hifi boys using them!
I agree that a 24V alternator and batterywould be better, but way more expensive! I've never used a winch of that type, what sort of current do they draw? I guess it depends on how you use it, if you're driving to a pickup, winching on the vehicle and then driving back over some distance I wouldn't see a problem. If you're picking up 10 cars in a day all within a 5 mile radius then I wouldn't expect the battery to last! I guess you'd have to try it and see.
Even so as the aux battery flattens the supply to the winch will drop but the alternator will be keeping up half of it.
What setup do the 4x4 guys use. They all have big winches and usually 12V. Do they need to take steps to protect the alternator? Cad you should know this just about every 4x4 I saw in Oz had one.
Steve