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seafox · 29-07-2007, 21:28

what battery is best for the anchor winch? A deep cycle or a marine starter battery.

The starter is designed for short bursts of high current. The anchor winch operates for a lot longer than the starter motor on the engine

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Vasco · 30-07-2007, 06:08

Seafox,

Are you contempalting a dedicated battery for the windlass? Most of the thinking nowadays is to run the windlass off the house batteries. Of course the engine is usually running when using the windlass. My windlass won't work without the engine running. In a engineless emergency the anchor can be dropped by loosening the clutch.

**Alan Wheeler** · 30-07-2007, 12:23

Vasco, what do you mean your windlass won't run without the engien running?? Yikes. Careful mate, you will burn out your alternator. Your battery should be capable of running the winch. You run the engione to maintain the voltage to the battery. The Alternator should not be supplying the current to the winch. If it is, you need a much bigger battery.
Or am I not understanding.

**Alan Wheeler** · 30-07-2007, 12:32

Now to answer the original question.
It's all about current and how the battery delivers that current. A deep cycle is not all that good at delivering a large bulk discharge of current. They tend to be too slow at doing so. A start battery will. A winch, especially under load is sucking a huge amount of current. So a Start battery is best at providing that short duration of large energy requirement. However, if the house bank is large enough in comparison to the current demand of the winch, then it is quite fesable to deliver that current from the house bank with no loss of performance from either winch or house bank. But the ratio must be fairly high and I am not sure what the difference should be. Maybe Rick can jump in here.
Now in saying that, it is the "technical" point of view. It is true that many, including myself, power the winch from the house banks. But I have 400Ahr of bank and about to go to 800Ahr. So I don't have a problem with current supply shared over 4 x 200Ahr batts. Plus the other reasoning is that I like to keep starting for just that and only that. Maybe I am being a bit over board there, but it's the way it is for the time being. It has worked for me so far with no issues.

hellosailor · 30-07-2007, 12:48

Wheels, I suggest the answer lies more in "it depends".

A group 27 AGM deep cycle battery can be used to start a one-kilowatt starting motor, according to several makers. Not because it is built for high impulse use like an SLI battery, but because it has so much power available that a one-kilowatt load can be dealt with, for short times.
(Battery capacity, about 80AH. 1kw load for three seconds, 69 Amp-Seconds, or about 0.2AH of load, unless I'm fumbled my math again. the plates have enough area to supply that "one quarter of one percent of capacity" from their surface, practically.)

Could be that a "dual purpose" battery, which has plates designed in a compromise of both, with sufficient capacity, would work well for a winch. "Depending" of course on the winch's draw and how long it was going to be used, versus the battery size.

The average SLI battery is designed and sized for a particular starter motor, i.e. a Group24 may be matched up with a 1 to 1.5 kilowatt starter, a Group 27 for the next larger motor, etc. all based on the fact that a starter motor also is not supposed to be run for more than 15 seconds in 20-30 minutes, and usually will be run for less than five seconds.

So...depending on what that winch draws, and for how long? Could be multiple good solutions. Lifting an anchor from 300 feet I'd suggest deep cycle and the engine running with good cables as well.
< G >

Vasco · 30-07-2007, 14:36

Wheels,

The Lewmar windlass on these boats is wired so that they will not operate unless the engine is running. There is some sort of relay/switch/fuse thingmajig that prevents the windlass from operating. It can be bypassed but I have kept the wiring the way it came. The windlass is power up and down, no freefall. As I said earlier in an engineless emergency I would loosen the clutch (a big nut and I have a large wrench always handy) and then the chain would freefall. The winch does run off the batteries but the switch thing is to prevent you from killing the batteries.

Steve Pope · 30-07-2007, 18:33

An interesting thread, I am converting from a manual single speed Goiot to a 2nd hand Lofrans Tigre and have been pondering whether to use some heavy welding cable or go to heavy duty tinned cable. The cost points me towards the welding cable and the fact that I already have it. Re the batteries I thought it was a given that you used the engine start batteries and not the house ones, I run 2 truck 12 volt batteries for starting and 4 Trojan T105 6 volt for domestic use with a bridge for emergency starting.

hellosailor · 30-07-2007, 20:01

Steve-
If you're lucky, go to Vegas. Otherwise...those welding cables are a very fine wire, and they will oxidize and take water damage much faster than battery cables will. I'd use fully tinned battery cables, or fully tinned "#3 Machine Wire" which is extremely close, differing AFAIK only in that the insulation isn't rated for engine compartments (heat and oil resistance).

I've come to learn that The Creeping Crud will attack any wire on a boat, no matter how well you think it is sealed, unless it is tinned. Of course if the welding cable is so cheap that you can afford to throw it out in five years, and don't mind doing the job all over again...(shrug).

I can't see why you'd use just the starting battery (a small distant battery) and alternator to power a winch, instead of selecting "ALL" and giving it every amp you can.

coot · 30-07-2007, 23:05

Quote:

Originally Posted by Vasco

As I said earlier in an engineless emergency I would loosen the clutch (a big nut and I have a large wrench always handy) and then the chain would freefall. The winch does run off the batteries but the switch thing is to prevent you from killing the batteries.

My windlass has a similar interlock with the engine. I considered defeating it so I could raise/lower the anchor under sail or in an emergency. But subtle details can make a big difference: my windlass does not require the engine to be running -- it requires the key to be in the ON position.

The implication here is that I can run the windlass without running the engine, as long as I don't mind listening to the engine fault (i.e. low oil pressure) alarm while I'm doing it.

**Alan Wheeler** · 30-07-2007, 23:57

Steve, as long as you seal the ends of the cables well, the welding cable will do just fine.
I seal the crimp and cable end by placing hotmelt glue on the cable end (after the crimp or/and solder of course) and then slid a piece of heavey walled heatshrink over it all. You can even buy heatshrink with the glue on the inside wall of it. Then heat the shrink down and the glue squezes in and gums up the entire thing and seals it from any water. I have fully tested this with something compleatly different. A cable that has a lug connected and immersed in Salt water four feet down and it has never leaked yet in three yrs.

stevemac00 · 31-07-2007, 07:10

seafox, probably a starter battery. A windlass motor is a starter motor. As you point out it runs longer than the 5-15 seconds but still doesn't drain the battery much (150A x 3 minutes is less than 8 amp hours) so a small starter battery (like a small Optima) will easily deliver that kind of current. Then you can put a relay charger will will deliver up to 15A to the battery and "refill" it in about 30 minutes from your house bank.

But if you have anchoring problems you could run out of battery therefore I (and many others) run off the house bank. It may never happen but I need to insure against it.

hellosailor · 31-07-2007, 08:25

Wheels, so what kind of zinc do you use on that cable under four feet of salt water?
< G >

Coot, I'm guessing your windlass/key interlock was set up as safety, to make sure an "authorized person" was on the boat and that stray sea lions or partygoers couldn't accidentally unhook your boat. Not a bad idea, really. You know, those drunken sea lions can be real pranksters.
< G >

vacendak · 14-10-2007, 23:53

still, on a bigger boat (>=40") dedicated windlass battery
should be considered seriously (because of voltage drop in long cables)
OPTIMA SPIRALCELLS might be the best option

S/V Antares · 15-10-2007, 10:25

I think A dedicated battery forward is a good practice on a "Larger" boat. Run reasonable size charging wire from your Charger /alternator. The shorter the distance to the load from the battery the better in cost and performance. Just a little Voltage drop will greatly reduce the performance and overheat the motor and and more often "weld" the relay contacts. Make sure you have a Battery switch for the system and do not forget that when measuring cable runs to measure both Pos. and Neg side for the total length for determining cable size. Then get bigger cable!