Outer Limits 4x4 Board

Can you run a 24volt winch on a 12 volt connection in my truck

You can hook it up, but you'll have bugger-all torque.

Unless I've misunderstood your question?

Cheers,

Scott

NJ SWB wrote:You can hook it up, but you'll have bugger-all torque.

Unless I've misunderstood your question?

Cheers,

Scott

yep it will run at approximately hlf speed with less than half the torque

so your 7hp motor would be a 3hp maybe? and half the speed.

deleted a post full of mis-information.

Mytqik wrote:Power = Volts * amps

Therefore if you cut the volts in half you will need to double you amps. Therefore your esiting 12V system had better be rated to carry a large amount of amps.

IE 4hp motor = 2.9kw = 2900Watts. Therefore on 12V it will require 2900/12 = 240ish amps. That is alot of current in anyone's language.

The drama will be that your winch motor will be designed to handle only half that amount of current & you may melt the internal copper winding.

Agree with above

Mytqik wrote:Power = Volts * amps

Therefore if you cut the volts in half you will need to double you amps. Therefore your esiting 12V system had better be rated to carry a large amount of amps.

IE 4hp motor = 2.9kw = 2900Watts. Therefore on 12V it will require 2900/12 = 240ish amps. That is alot of current in anyone's language.

The drama will be that your winch motor will be designed to handle only half that amount of current & you may melt the internal copper winding.

No.

The current draw varies depending on load (and hence motor speed and "back emf.") The highest current draw will be at stall, when you have no back-emf and effectively a resistive load. Half the voltage will give you half the current.

If 12V stall current is higher than maximum load current under 24V conditions (what stops the motor stalling normally?) then you're in trouble. If the 24V motor is designed to cope with stalling (even if only briefly) you can't draw more current on 12V.

If you really want to know:

1. Find the spec for maximum rated continuous current.
2. Measure the resistance R across the motor terminals.
3. Divide 12 by R (above) and you have 12V stall current.

If current in 1 is greater than current in 3, you're fine!

Scott

What a bout a 12v to 24volt inverter

Not sure if the 24volt solenoids will reliably fire on 12 volts?

there not 24V solinoids, they are 12V, the 12V and 24V unit has the same solinoid, just a different wiring method

BTW a 24V motor on 12V will draw only half the current that it would at 24V

Mytqik wrote:Power = Volts * amps

Therefore if you cut the volts in half you will need to double you amps. Therefore your esiting 12V system had better be rated to carry a large amount of amps.

IE 4hp motor = 2.9kw = 2900Watts. Therefore on 12V it will require 2900/12 = 240ish amps. That is alot of current in anyone's language.

The drama will be that your winch motor will be designed to handle only half that amount of current & you may melt the internal copper winding.

If this reasoning were correct then running the winch motor at one volt would blow it up instantly, because it would have 24 times the intended current running through it. Also, it would last much longer at 48V because then it would only have half the current.

So I don't think this is right. The formula to apply first is V=IR, or volts = current * resistance.

This is the same as:

Current = voltage / resistance

The resistance in the winch motor isn't going to change when you change the voltage. So effectively if you halve the voltage, you halve the current.

THEN you look at the power output, and that is current times voltage as suggested. So if you have half current, half voltage, then if anything you'll get 1/4 total horsepower.

The load on the motor will throw these calculations out a bit, but to get an idea of how much grunt the winch will have, just consider how well your starter motor works if your battery drops down to 6 volts. It's virtually useless.

It *would* be possible to run a second battery to get 24V. The only problem then is keeping the second battery charged with your single 12V alternator. This could be managed with a couple of solenoids; you have the second battery in parallel for charging, then it switches to being in series (24V) for winching. A bit complicated but not that hard really.

What's wrong with just running a 12V winch on 12V?

Jason

The 24volt winches are much faster.

The second battery Idea sounds good Chimpboy.

I might just bite the bullet and put in a second 24volt alternator just for the winch and leave the rest of the car electronics on 12volt.

Keep em coming peoples.

LudaCris

Chimp boy you are 100% correct. Please ignore my above post, it is wrong. I put the cart before the horse so to speak.

Running the 24V motor on 12V will only halve the line speed & 1/4 the power, so it will be prety useless.

Sorry to anyone that I mislead.

ludacris wrote:The 24volt winches are much faster.

The second battery Idea sounds good Chimpboy.

I might just bite the bullet and put in a second 24volt alternator just for the winch and leave the rest of the car electronics on 12volt.

Keep em coming peoples.

LudaCris

i think this is the way to go chris, winches are designed by an electical engineer........they are suposed to know what there on about...... and most of the time there preety spot on, dont forget this winch would have undergone extensive testing before being sold as reliable. i assume you want to use a winch that is out of warrenty, because it would void any warrenty if you did do it. i think your asking for trouble if ya put a 12V on 24V...........

just my educated opinion

ludacris wrote:What a bout a 12v to 24volt inverter

For the power levels required for winching, not an option. Even high efficiency inverters will be wasting too much power at these levels - if you could build one.

Go the 24V alternator option.

Cheers,

Scott

ludacris wrote:What a bout a 12v to 24volt inverter

Invertors are dc to ac.

you could convert your alternator, starter and lights to 24 volt and use a switch mode dc to dc convertor to power your 12v accessories. The 12v lights could be wired as pairs in series to make them 24v.

I dont think you would find a dc to dc converor that could handle the current draw of a winch.

Dual 12v and 24v systems are probably more practical.

Having a single 24v alternator to charge a pair of 12v batteries in series (for 24v) and running your 12v systems from 1 of the batteries, might sound appealing, but the problem is that 1 battery will be drawn down more than the other and the other, that isn't drawn down will fail prematurely from being overcharged.

American magazine Fourwheeler or Petersens 4wheel And Offroad (Can't remember which one)had an article on this some time ago.
They had a 24-Volt battery setup in addition to the car's original 12-Volt, and a special voltage converter/charger combo charging the 24-Volt setup.
Downside is that when you've discharged the 24-Volt setup, the converter/charger can't power the winch alone...

If there's space for two alternator, i second the opinion that dual setup is better....

How about this - running a 24V winch with a constant load (ie winching up a hill) Now whether you run 24V or 12V both setups will have to draw the same current because the load is the same in each case. So with the 12V setup the motor speed will be much slower (which creates less back EMF which allows the 12V to push the same current).

So with both setups they both draw the same current but with the 12V the motor spins much slower which create less windage cooling of the windings plus the winch effort will take much longer to complete. So running 12V in a 24V winch could burn the motor out???

Have heard of half stuffed batteries (ones that done produce full voltage)killing engine starter motors by the same process.

Apparantly the hot winch challenge setup is to use a stock 12V winch and run it at 24Volts. Just be carefull that you dont stall the motor up too much cause it will blow up - bloody fast line speed though.

Sam

Strange Rover wrote:How about this - running a 24V winch with a constant load (ie winching up a hill) Now whether you run 24V or 12V both setups will have to draw the same current because the load is the same in each case. So with the 12V setup the motor speed will be much slower (which creates less back EMF which allows the 12V to push the same current).

So with both setups they both draw the same current but with the 12V the motor spins much slower which create less windage cooling of the windings plus the winch effort will take much longer to complete. So running 12V in a 24V winch could burn the motor out???

Have heard of half stuffed batteries (ones that done produce full voltage)killing engine starter motors by the same process.

I've not heard of this myself, but your theory makes some sense. The only part you've not covered is that current alone isn't the whole story - heat is generated from the power, which is V*I. With half the voltage and the same current you'll still only have half the power. But with less cooling from less turbulence, and operating for longer, the motor could eventually overheat to failure.

Half-stuffed batteries usually have a higher internal resistance, which means that terminal voltage falls off faster as current rises. I'd want to see it happen myself before I'm convinced.

Cheers,

Scott

NJ SWB wrote:Half-stuffed batteries usually have a higher internal resistance, which means that terminal voltage falls off faster as current rises. I'd want to see it happen myself before I'm convinced.

Cheers,

Scott

Me too......

Sam