Anchor Winch Power Consumption vs Batteries

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Slipperman

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I am looking at fitting an electric anchor winch for the first time. Looking in various catalogues, electric power consumption is given for different models at between 60 and 120 amps. Not sure how this relates to my battery capacity. I have two 95 amp/hour linked in parallel - will this be sufficient to lift, say, a 15kg anchor plus some chain, and still leave me some battery power for all the usual stuff? Apologies for being an electrical thicko!
 
Most leccy windlasses have a 100amp breaker, or thereabouts, so can't draw more than 100 amps (and usually rather less). Allowing a (generous) 5 minutes to lift your gear, that's 100A x 1/12hrs, or approx 8Ah...small in terms of your battery capacity. However, it's prudent to run your engine (preferably at more than tickover) to augment the battery(s) whilst using the windlass.
 
macd said:
However, it's prudent to run your engine (preferably at more than tickover) to augment the battery(s) whilst using the windlass.
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So why is that? Perhaps so that the higher voltage results in slightly lower current in the cables for the same power? Or to start with a higher voltage so that the windlass is still seeing what it should despite volt-drop in the run forward?

I know "always have the engine running" is standard advice, and I've sailed on charter boats where the windlass circuit is disabled otherwise, but if the energy actually extracted from the battery is relatively small (due to the short run time) then it can't be in order to top up capacity.

Pete
 
PCUK said:
If the battery isn't fully charged and the engine isn't started first then you may haul the anchor and have no power to start the engine. Simple common sense!
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How many boats big enough to fit an electric windlass don't have separate engine and service batteries? :confused:

Pete
 
macd said:
...there's also the fact that windlass manufacturers generally recommend running the engine.
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Sure - I'm not suggesting one shouldn't, I'm trying to understand why.

It's looking increasingly likely that I will soon be the part-owner of a boat with (for the first time) an electric windlass, so it is of some relevance to me.

Pete
 
Think it is as much a matter of pragmatism as any rational reason. My windlass does not need the engine to run and I have often used it for short bursts - hardening up against the anchor when berthed stern to, or letting out some more rode with no ill effects. However, you would normally have the engine on when using it for any length of time, so the drain on the battery is virtually zero.
 
Thanks for the replies guys, just what I was looking for. I do have a separate engine start battery, but have noted the point about running the engine and guess that would probably be the norm.
 
I guess it may be to put less strain on the battery - 80amps drain is pretty high for a battery, but with 50 amps being supplied by the alternator it's a less savage draw on the battery?
 
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