Heavy Duty Car Electrics

[sotal]

I think I've sorted out what I need but if anyone can confirm that my quick "ms paint" circuit diagram is correct and what kind of switch I need - It would be helpfull.

I need to connect a 24V Motor up to a 12V Vehicle, easy I need two batteries, but I also want to be able to use the second Battery as a helper Battery to boost the first Battery to help starting and obviosuly the normal circuitry needs to carry on working at 12V even when the motor is running at 24V. Also I would prefer it if when the battery is connected as a booster battery it would charge from the alternator as well.

I have attached my quick circuit diagram which I think should allow me to do it.

I think the circuit is correct and I think I need a double pole, double throw (dpdt) switch to flick between series and parallel. The switch needs to be rated to 230A at 24V

Question 1) Can anyone see any problems doing it like that?

Question 2) The motor comes in 2 versions 12V and 24V - We got the 24V (it was cheap!) In the manual it says that the 12V model requires a 60Amp Alternator and a battery capable of delivering 440 cold crank amps, but it doesn't mention the 24V one. Will it matter that the alternator is only on half the circuit and only 12 Volts?

Question 3) Does anyone know where I can find a suitable swicth - I tried Maplins but they didn't have anything heavy duty enough

Thanks for any help

[Flat Pack]

Can't think of any reason why it fundamentally won't work, couple of things to think about though. Will the alternator be up to the job of charging 2 batteries in parallel? I don't know, might not be very efficient at it. Second one is the booster Battery will get discharged pretty fast while you're running the motor, you'll be drawing a lot of current from it and have no charge circuit in place for it. You'll have to be careful to avoid raising bits of the electrics to 24v that you don't want to too :)

I don't think you'll find a switch capable of passing 230A at 24V, that's well over 5KW of power! Best bet would be a solenoid (as used to switch power to starter motors), I guess you can find them in dual pole but I've never really looked. I'm not sure you can get relays that'll switch that much current either.

[mikeb]

What the funk are you up to? Trying to convert your celica into a Prius style hybrid?

The currents you are talking about are mahoosive, you will need monster cable and switching/relays. Please tell me 230A is a typo, but then you mention 400+ cold cranking amps! You do realise that 440A at 12v is the equivalent of 7 horsepower!

I don't think the circuit you sketched will work, you said you need a permanent 24v to the motor, but when the switch is in the other position it will only get 12v ? I assume you don't want to run motor whilst simultaneously having both batteries on charge (i.e. in parallel)?

You might well need a larger alternator to keep both batteries charged.

I will try and draw something up for you.

EDIT: This is my take on it, it's quite similar to what you've drawn.

EDIT 2: Corrected version!

[sotal]

It's for my off-road project :D

The motor is a 6.2 hp Recovery Winch. The cabling involved is extremely thick.

It only pulls 230A at full load, and you can only run the winch for a minute at a time. Full load is 6000lbs. The 12V version requires 400Amps at full load!

I think fundamentaly your circuit does the same as mine. It doesn't matter that the winch is still connected at 12V as it won't be used at the time.

We got it very cheap from a friend who had, had a rear end smash, they had said it was 12V and had used it a fair few times on their vehicle which is 12V - So I presume it would work at 12V put perhaps be only half the power with it having the 24V magnet? We've got a spare Battery and a rear mounted Battery cage and loads of the heavy duty cable (although it's all black)

So we just need to sort out what kind of switch to use. I was imagining one of those big levers switched. It is possible to just change a couple of wires over each time I want to use it but it would just be neater to flip the switch!

If the alternator won't be powerful enough then I guess I would just leave it in 24V mode, so only the first Battery is being charged, then flick it to 12V mode to boost on startup if required, then once it's started flick it back. Then keep the second battery charged from the mains at home??

Any other ideas??

[daktari]

I take it this is for the Landy??? Mikes should work OK. Some of the 4x4 boys locally have done some strange things with electrics, but the one thing i noticed is the abundance of MK domestic electrical fittings. albeit waterproof. So i guess that you need to be looking at some heavy duty domestic or industrial switces. And you need to be looking at 100amp applications just to be on the safe side. Don`t know where you would get them though.

Just read your reply. What make is the winch. ???

[sotal]

The Winch is a Superwinch X6, if you look on the superwinch site you can download the full manual etc.

I was thinking about mains switches and if they would work the way I was thinking it was as I half the Volts I could double the rated amps??

So a 50A 240V Switch would be

100A @ 120

200A @ 60

400A @ 30Volts

Then I thought how will I connect a cable thats not far off an inch in diameter to a mains switch!!

[daktari]

An inch? Surely thats a bit of overkill on someones behalf... :D You`d get away with using H/D starter motor cable for that. Pinch some off a passing lorry. It`ll run happily on 12V

[sotal]

It's not quite an inch but it's not far off. I'm guessing about 3/4 of an inch. It is heavy stuff.

You say it'll run happily on 12V are you sure?? Will it run at full power or half power??

Initially I thought they were the same model and it could run at either 12 or 24, but apparantley there is two different magnets inside

[daktari]

It's not quite an inch but it's not far off. I'm guessing about 3/4 of an inch. It is heavy stuff.

You say it'll run happily on 12V are you sure?? Will it run at full power or half power??

Initially I thought they were the same model and it could run at either 12 or 24, but apparantley there is two different magnets inside

Yeah just seen there are 2 versions. 1646 is 12V and 1647 is 24V It should have an ID plate on it somewhere. Usually the motor casing. I wouldn`t like to put 24V through the 12V I don`t know how well they cope with overloading.

[mikeb]

I was thinking about mains switches and if they would work the way I was thinking it was as I half the Volts I could double the rated amps??

No, the voltage is irrelevent. Domestic mains stuff is 13A whether you put 230v or 12v across it doesn't matter.

I don't know what size/rating your Battery is, but 230A is a big load.

The motor voltage is nothing to do with the magnets, but the windings on the armature. But basically, if you run a 24v motor at 12v it will run at half speed (which might be more appropriate in your case).

[sotal]

Running at half speed will it still have the same power? ie will it still pull 6000lbs ona single line?

If so it may well be worth just wiring it up as 12V

[daktari]

Running at half speed will it still have the same power? ie will it still pull 6000lbs ona single line?

If so it may well be worth just wiring it up as 12V

If you use a pulley block and double the cable up. 12V will get you of most things. Not sure about a vertical pull, so avoid cliffs if at all possible.

[mikeb]

Running at half speed will it still have the same power? ie will it still pull 6000lbs ona single line?

If so it may well be worth just wiring it up as 12V

No, it will have less power. You are probably best to try it at 12v first and see if it will pull what you need before wiring up 24v.

As for switches, the winch manufacturer lists some on their website I believe. Otherwise, you might get away with some solid state relays, but the highest rated I've seen are 100A or so.

[sotal]

Thanks for the advice guys

Mike the problem with wiring it up at 12V and seeing if it's good enough is that I'll have to go and get stuck in some mud to see, then if it isn't good enough I'll look a right fool stuck in the mud with a huge winch

Daktari - I was going to get a pulley block anyway as it's supposed to effictively double the max load, or half the strain on the wire rope at 6000lbs.

I hadn't noticed any switches on the superwinch site - but I'll go and have a look now and see what I can find

Cheers

*******************

Just checked the superwinch site - they don't do any suitable switches - they've got some for the smaller winches and the others are just for the remote control

[GIDDLEPIN]

The last job I worked at was a cravan transport firm using 24volt winches. If you just want a basic on/off switch why not go for a Battery isolator? they are a reasonable price and would take all the amps you would need.

[mikeb]

Mike the problem with wiring it up at 12V and seeing if it's good enough is that I'll have to go and get stuck in some mud to see, then if it isn't good enough I'll look a right fool stuck in the mud with a huge winch

Just checked the superwinch site - they don't do any suitable switches - they've got some for the smaller winches and the others are just for the remote control

Well, if you use your original circuit you can operate the motor at either 12v or 24v by changing the switch over.

I was looking at the remote control swiches on the superwinch site, now realise they're not what you are looking for.

[sotal]

Well, if you use your original circuit you can operate the motor at either 12v or 24v by changing the switch over.

Yes but if I find a suitable switch to make my circuit up, I won't need to run at 12 Volts

I know what you mean though - I make the circuit up minus the switch to start with then if I do get stuck try it out at 12 Volts if that doesn't work then manually change the wires over to give me 24 Volts.

Giddlepin - It's not just an on/off I need - it needs to be dpdt otherwise an isolator switch would probably do. Maybe I could bolt two together?? :D or if they make a double isolator switch to isolate two circuits at once??

I guess I might be able to use something like this:

http://www.thetoolboxshop.com/sess/utn;jse...%3Fa%3D0-605-26

but at that price - I'll just do it manually

[GIDDLEPIN]

Why not use solenoids then?

[sotal]

********************************************

Something like this is what I originally had in mind:

http://cgi.ebay.co.uk/WYLEX-4-POLE-100-A-I...1QQcmdZViewItem

I might try something like that - if it's too much it'll start to get warm and I can turn it off??

Why not use solenoids then?

I don't really know enough about them. The winch itslef has got two solenoids in the control box which switch the winch forwards and backwards when you press the buttons on the remote.

Other than that I would have no idea how to wire them up, and I could see a potential problem using two solenoids if one was quicker than the other I would get a short

[GIDDLEPIN]

The only way you would get a short would be if you had the button pressed on the winch control swithch at the same time, the motor won't draw any power untill one of its two solenoids are activated