Transform Your Winch: How to Convert an Electric Winch from 12V DC to 120V AC"

[bskramer]

i have an electric winch that runs off a 12v dc car battery and i want to run it off of 120v ac house electric current. is this possible, and if so how would i do it?

thanks for any help

 

[blaunacht]

You use inverter and then you use transformer for increasing voltage.

 

[cjameshuff]

You use inverter and then you use transformer for increasing voltage.

That's the wrong way around.

bskramer: you need a 12VDC power supply capable of supplying enough current to run the winch. It may draw considerably more current than a typical wall-wart or other small supply can handle. Does the winch have any markings that would give an idea what its current requirements are? What sort of situation are you using it in...does the supply have to operate outdoors or be mounted onto something?

If usage is intermittent, you might get what you need from a trickle charger and a 12 volt battery. Not the best solution, but a simple one.

 

[mheslep]

Why not buy a 12V car battery (~$50) and and a 12V battery charger (~$80) (which is essentially a 120VAC to 12VDC converter?

Or, if you have an old out of service tower computer (PC), you might start with ripping the power supply out of it, as they are 120VAC to 12VDC (and other outputs). They're typically 2-300W, though I'm not sure how much of the load can be placed on the 12VDC outputs, and any useful car attached winch is going to want >>10A @12V. No loss if you blow it though.

 

[bskramer]

thanks the winch draws on average 70 amps and peaks around 90. will a 350W power converter from a tower PC be able to handle that? when dealing with amps and Watts what is the equation that compares the two, and how do I know if the power converter will be able to handle the 70-90 amp load of the winch. is it the Watts that determines the max load capable of being supported?

 

[mheslep]

thanks the winch draws on average 70 amps and peaks around 90. will a 350W power converter from a tower PC be able to handle that?

No. Go w/ the battery and battery charger.

when dealing with amps and Watts what is the equation that compares the two,

http://en.wikipedia.org/wiki/Electric_power#Direct_current

and how do I know if the power converter will be able to handle the 70-90 amp load of the winch. is it the Watts that determines the max load capable of being supported?

You need to know both current and voltage of the load, giving you Watts.

 

[DaleSwanson]

The equation you want is amps * volts = watts. So:
90 amps * 12 volts = 1080 watts
1080 watts / 120 volts = 9 amps in a household circuit.
There will be some losses from inefficiency as well.

They sell https://www.amazon.com/dp/B000P7O5DG/?tag=pfamazon01-20. Note that the one linked to claims 5 amps, so it isn't powerful enough for your purpose. I'm not sure if you'll be able to find one that outputs 90 amps, as that is quite high.

I think mheslep's battery + charger combo idea may be your best bet.

Edit:
It's probably a good idea to mention that typical car batteries don't deal well with being drained completely and then recharged. If you are going to do that, you may want to go with a (more expensive) marine deep cycle battery. A typical car battery is rated at about 100 amp hours. Meaning your (almost) 100 amp winch will run for about an hour. If you only plan on running the winch for a minute or so at a time and then allow for recharging a car battery may work fine.

 

[cjameshuff]

mheslep's right...go with the battery and charger. Lead-acid batteries are used largely because they're good at giving large amounts of current, for things like starter motors. A power supply capable of giving 90 amps at 12 volts straight from the wall is probably going to be expensive, and also going to be likely to flip breakers/blow fuses.

A couple cautions, though:
Make sure you have proper ventilation to prevent hydrogen buildup. Lead-acid batteries can produce hydrogen when charging.
Get a charger that automatically turns off when the battery is charged. The above hydrogen production is caused by overcharging, which also damages the battery.
90 amps is a good bit of current, and many lead acids can deliver a lot more. Be very careful not to short that thing out.

edit:
Here's an example of what you'd need to do this with a power converter: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_231686_-1

 

[bskramer]

Thanks

 

[mheslep]

90 amps is a good bit of current, and many lead acids can deliver a lot more. Be very careful not to short that thing out.

Good point. A $500 AC/DC power supply will include short circuit protection. A hard short in the output of a 12V car battery it will destroy everything in the circuit up to the point of the short.

 

[bskramer]

hard short?

 

[mheslep]

hard short?

Versus a brief incidental contact, e.g. momentarily swiping battery jumper cable clamps together.

 

[sophiecentaur]

I think a 150A fuse would be quite adequate protection for your battery and leads. Also, a good, 'intelligent' battery charger would give you maximum use of the battery (duty cycle) whilst charging it at a safe , optimal rate.
The best chargers cost a bit though.