Winch amp draw

[nismo4x4]

hey guys something doesnt make sense. Im looking at buying a 12000lb winch which apparently draws 400amps...the YD25 alternator is rated at 130amps...

bit confused as im not keen to hear a pop and fork out for a refurbished alternator...

 

[KraftyPg]

Got a spec sheet for the winch? Or website where such a thing exists?

 

[bm0]

OK I am not an expert on these things... Old.Tony will probably drop in shortly with a much better explanation... however in lieu of that...

Your battery (starting) will have a CCA of about 680CCA (or is it 660?) which means it can output 680 amps for a short period of time for the purposes of starting a motor (with a starter motor) Essentially running your winch is the same concept.

Your alternator will not generate enough current to run the winch alone, which is why you have your battery as part of the system.

Your alternator will however bring the voltage up to 14ish volts (someone will correct me with an accurate figure for the Nav) which lowers the current required for the winch to do the same work.

The alternator will also recharge the battery after winching.

In short, I cant see how it will cause damage to your alternator and whilst I don't own a winch (yet) I could see how that sort of current draw could be possible on one of these winches at full load.

brad

 

[bm0]

just to add this in.. i found this on the Tigerz11 webpage, it shows how the current draw increases as load on the winch does. Tigerz11 recommend a 650CCA battery for this winch.

Line Pull Line Speed FPM (m/min) Motor (Amps)
0 22ft (6.8m) 80
4000 (1814) 11.5ft (3.5m) 175
6000 (2722) 9.8ft (3.0m) 230
8000 (3629) 8.2ft (2.5m) 280
10000 (4536) 6.8ft (2.1m) 355
12000 (5443) 5.6ft (1.7m) 400


taken from here

 

[scooba_285]

what cca do the navs have?

 

[Old.Tony]

bm0 has it right.

While the winch and starter motors will draw several hundred amps, they only do it for a short time. Let's run some numbers so you can see how it's not really that bad.

Krankin discovered that the D22 (D40 will be similar) draws between 500 and 550A to crank the engine over. You do that for about 3 seconds usually, and the engine is going. In amp-hours, that's 550 * 3/3600 = about half of one amp hour. It will take your alternator all of about 10 seconds to restore the battery's charge.

A winch operating at maximum current (which they don't do for the entire time) will draw (say) 400A. You will winch for about 1 minute, maybe 2. 400A times 2/60 = 13A of total draw. A 90A alternator running at a third of its potential will put that power back into the battery in about 10-15 minutes.

Don't worry about your alternator. The power isn't coming from there, it comes from your battery. The alternator just replenishes the battery later.

While you're winching - keep your engine running just to be on the safe side.

 

[bm0]

what cca do the navs have?

According to Century, my D40 needs a 660CCA battery.. The factory one that i still have in my 08 does not specifically show a CCA rating, but safe to say it is equal to or greater than 660.

they dont list a D22... *insert pun about D22 inferiority here*

 

[Geoff3DMN]

they dont list a D22... *insert pun about D22 inferiority here*

D22's have twin cranking batteries from the factory not one like a D40 *insert smug look*

 

[justdrinkbeer]

Tony is on the money once again, just to pipe in with an addendum:

You will want to be running the car while winching, it will keep the voltage up & the battery topped up a bit while winching, also, you don't want to be winching non stop until the battery goes flat, you'll burn the winch out before you do.

If you bought it with you're own money you'll want to look after it, i'd be reluctant to winch for more than 30 secs without a short break

 

[nismo4x4]

ahh ok thanks fellas...the winch spec sheet only showed amps so assuming its talking about CCA not the alternator amps...thats cool then. iv running a CAT battery with 780CCA.

THanks again fellas

 

[scooba_285]

does the alternator put charge back in the battery quicker when the revs are up higher? or is it the same as when its idling (governed by something somehow)???

 

[nismo4x4]

well i had my fair share of flat batteries and jump starts. And it did kick over alot better when revving higher revs.

 

[Old.Tony]

does the alternator put charge back in the battery quicker when the revs are up higher? or is it the same as when its idling (governed by something somehow)???

Short answer - yes.

The more revs, the more power the alternator CAN put out. It is regulated by the alternator (and ECU in the D40, not sure about the D22).

When idling, the alternator really can't put out a lot of power. If you're winching at night, it's best to have someone sit in the driver's seat of the winching vehicle and hold the RPM up a little (1200-1500rpm ought to be sufficient while actively winching).

 

[BravoBrad]

I miss my hand throttle.. it was very handy when winching.