Winch Wiring

[milky]

I've got the winter pack with the dual battery setup and was wondering if it's possible to wire in a 24v winch?

[cooperman]

Simple answer is no as the surf runs the 2 batteries in parallel making it 12Volts only.

[milky]

I've been reading around on different forums and the replies seem to be that it is possible. I need to run everything of the one battery, set up a caravan split charge for the second battery and set up new wiring connecting the first and second battery to the winch, with isolators so that they and the winch ar only connected when in use.

What do people think on this? Will the surf run everything from one battery or not? Will having a 24v loop connected when winching affect anything everything else which is just connected to teh one battery.

[TFB]

Is there any reason you want a 24V winch?

With a little bit of a wiring mod you could do it.

You'd need both batteries in parallel for most of the time, and when you wanted to winch you'd need a decent soloniod to throw them in series with the vehical wiring fed off of just of one battery.

Overall I'd prefer a 12V winch as despite the reduced current draw of a 24V, there's too much scope for things going wrong with the wiring e.g. a welded relay contact that could end up frying the cars electrical system

Regards

TFB

[sparkyaj]

you could use diodes to prevent one bat back feeding into the other one, but i would strongly suggest using a 12v one for ease.

[mud skipper]

i would seperate the batteries and run the engine off one battery and all ancillaries off the other thru a split charge system. on a landy you can rig up a second alternator and run both batteries seperatly.
the battery that you connect the winch and accessories to ideally needs to be a deep cycle type.

how much winching are you planning on doing?

[sparkyaj]

also tip for the day - try doublingup 6v bats. deep cycle will last much longer. thats what we use on cherry pickers and they work a treat under load.

[milky]

it is all down to cost. i got the winch for £40 with solenoid, plate and lead, and was wanting see if i can wire it in for about the same.

i don't intend to use the winch that often hence trying to save as much cash as i can. Plus my surf is my toy and if i tell my wife i'm off to spend another few hundred quid on a winch i don't tthink she'd be happy.

[TFB]

Plus my surf is my toy and if i tell my wife i'm off to spend another few hundred quid on a winch i don't tthink she'd be happy.

now that I can understand!

This circuit should work.

Under normal conditions the batteries are in parallel and both being charged by the alternator. There is a double pole switch or relay that will switch the batteries into serial mode with the existing cars electrical systems being fed across just one battery and the winch solenoid being fed across both batteries

The switch or relay will need to be capable of handling the current from the winch without welding the contacts shut. The plate on the winch should tell you the current or power.

I'd get a 2nd opinion on the diagram before installing to it as I've not long woken up and only on my 3rd espresso.

Regards

TFB

[adpsimpson]

To answer an earlier question, the Surf is fine with only one battery for running the usual vehicle loads - we've got ours set up like that, with a deep discharge leisure battery in the other spot, and it's grand.

[milky]

Thanks for all the input.

The diagram was a massive help and i think it is what I'm going to try. My only issue now is the maximum current of the winch is 400amps and the maximum continuous current of any switch I've found on the market is 230 continuous but this one at maplins seems to have a higher peak

After spending time looking at the diagram I've also realized that if i change the switches in the wrong order i will send 24v's to the car before sending to the winch. If i switch in the correct order i will send 12v's to the winch before sending 24v's to it. I've attached the winch specs showing the current table.

As I'm new to winching how often am i likely to use full draw and for how long? Am i likely to melt the switches?

[mud skipper]

i have had to use my winch for periods of upto half an hour on several occasions at full power, when your winching a dead vehicle up a bank or through a mud run then it can take some time to recover them.

that winch in your post is a slow but powerfull one like you would find on the back of a recovery truck, 265.1 ratio.

what do you want from your winch?

[TFB]

Most of the switches with a high current rating are simple make/break and not changeover. The idea is that both switches are thrown at the same time, ideally using a dual pole change over contactor. The only types of that kind of unit I've found are heavy duty industrial control units at £300!.

Another alternative is to use two of these with the coils wired in parallel so they will switch at the same time.

Regards

TFB

[adpsimpson]

Following this topic with interest. Two things - firstly it should be relatively easy (and cheap) to rig up some heavy duty starter motor relays, which you could get from a breaker yard, to handle the current. Although the maximum current draw may be 400 amps, that's very dependent of speed and torque - I'd have thought you'd struggle to make it put that much power out pulling a Surf. And starter relays can typically handle large currents quite well. However since their simple make or break switches, you may need 4 of them. A simple double-pole double-throw switch could be used to switch them - I'll have a go at a circuit now, just for the interest.

Secondly, you'll do no damage to the winch by supplying it with 12 volts for a short period, but you'll do massive damage to the truck by supplying it with 24 volts for a short period. If you don't have a good, automated switch unit, working out the order in which to switch things therefore would be pretty important.

[adpsimpson]

Here's my attempt at working out how you could do this safely and cheaply.

Two high-current relays control each of the circuits, wired to a SPDT (two way) switch. So when the switch is changed, all 4 relays are disconnected for a bit (one battery fully isolated).

My diagram (excuse the sloppiness and non-standard symbols...) shows a switch with side A and B. When A is selected, relays 1 and 2 are active, and the circuit in blue is connected (12V parallel batteries to the vehicle, nothing to the winch). When B is selected, relays 3 and 4 are active, the circuit in red is connected (12V to vehicle, 24V to winch).