Electric Windlass - what battery/electrical setup?

[Babylon]

I'm planning on fitting an electric windlass (http://www.seateach.com/South-Pacific-Vertical-Windlasses.htm) which will have a 1000w motor drawing a typical 25A (12v); I don't know what the max draw is.

A couple of questions:

1. Can I run the windlass off my normal domestic bank of two 110Ah deep-cycle batteries without damaging them, or do I need a separate car-battery (ie big cold cranking amps)? I'll have 80m of 8mm chain on a 35lb anchor, so when its all out and at a retrieval rate of 18m/minute that'll take over four minutes of hauling up a lot of weight and therefore a big draw on the batteries, unless the engine is running.

2. What would the esteemed panel advise re switching? A foot-switch on the foredeck or hand-switch (but there is no anchor locker with a lid), or a 5m remote control lead, which would presumably mean I can handle anchoring/weighing direct from the cockpit?

 

[prv]

Yes, run the windlass off your main bank. Just make sure you work out suitable cable sizes to go the distance without excessive volt drop. Then buy them as welding cable rather than anything with marine in the name!

The usual reason for a separate battery is to avoid having to run large cables through the boat. But to me this seems like a poor tradeoff, as the cost, disruption and complexity of a whole extra battery is surely worse than that of fitting big cables.

As for switching, that's down to personal preference. None of the standard approaches are bad, but personally I would have a wireless controller (usable from anywhere on board, no exposed electrics to get wet) and a backup wired one stowed in the forecabin. When the wireless controller ends up with flat batteries and you can't find the spares, or the whole thing gets dropped over the side, you can crack open the forehatch and lead the cable for the backup controller out on deck that way.

Wireless control boxes can be had for under a tenner on eBay. The handheld unit is not waterproof, but could easily be made so by opening it up and sealing the circuit board in a plastic bag, then reassembling.

Pete

 

[pvb]

It's certainly cheaper, easier and more practical to run the windlass off your domestic bank. The engine will mostly be running when you're using the windlass, so most of the current should be supplied from the alternator anyway. A dedicated battery adds complexity and cost, not to mention additional weight up front.

As for switching, I find that foot switches are convenient, especially as on my boat the chain tends to pile up in the chain locker and needs "adjusting" frequently so I have to be near the windlass anyway.

 

[Tranona]

Yes, wire it to the house battery. In practice you rarely have to retrieve that amount of cable, nor do it without the engine running to keep the battery charged while you are using it. I have my remote on a wander lead wired inside the forecabin and take it out through the hatch. Avoid any plugs or cables in the anchor locker as this results in the cable getting too close to the windlass - guess how I know the consequences! Similar with foot switches, they limit where you can control the windlass from. A radio controller is useful to work the windlass from the helm.

 

[vyv_cox]

My advice pretty much matches prv's, with some detail changes.

1. Run cables forward, not adding an extra battery. My chain, anchor, batteries are the same as yours, except I have now changed to 3 x 110 Ah batteries. I ran 35 mm2 welding cables forward, they have now been there for well over 10 years with no problems. I occasionally take up or lower a small length of chain without running the engine but normally it would be running for any retrieval or laying operation.

2. My Maxwell came with a wired switch for the cockpit, which has proved to be a superb arrangement for Mediterranean use. In addition to that I have footswitches on the foredeck, used mainly for normal anchoring as opposed to stern-to. I'm not opposed to wireless switching but hard wired ones have served us well for a long time.

 

[prv]

Yes, wire it to the house battery. In practice you rarely have to retrieve that amount of cable.

With a 25 amp draw and 220 Ah of battery, he could wind in cable for four and a half hours without doing serious harm! I'm quite certain that nobody has that much chain to retrieve

(OK, I know it's not quite that simple with large currents, but it illustrates that flattening the battery is not really a concern, whether the engine is running or not.)

Pete

 

[pvb]

With a 25 amp draw and 220 Ah of battery, he could wind in cable for four and a half hours without doing serious harm!

Err, about half that time - the Peukert effect is stronger than people think! Still ample time to retrieve most anchors though...

 

[Tranona]

With a 25 amp draw and 220 Ah of battery, he could wind in cable for four and a half hours without doing serious harm! I'm quite certain that nobody has that much chain to retrieve

(OK, I know it's not quite that simple with large currents, but it illustrates that flattening the battery is not really a concern, whether the engine is running or not.)

Pete

Babylon raised it as an issue in his original question, so hopefully he now knows it is not!

 

[Sans Bateau]

IMO the best set up is to have the windlass wired to the starter battery, you only operate the windlass after starting the engine. Why do it this way?

1. The engine starter battery is better matched to the type of current draw which the windlass will take.
2. Wiring to the house batteries could see you having to manually raise the anchor. Imagine you spend three nights at anchor in the summer, fridge on, playing some music in the evening, the water pump, the shower pump all running the batteries down. You then come to raise the anchor to find (possibly) there is not enough juice to do so.

This is why the windlass is wired to the starter battery on Galadriel.

 

[pvb]

IMO the best set up is to have the windlass wired to the starter battery, you only operate the windlass after starting the engine. Why do it this way?

1. The engine starter battery is better matched to the type of current draw which the windlass will take.
2. Wiring to the house batteries could see you having to manually raise the anchor. Imagine you spend three nights at anchor in the summer, fridge on, playing some music in the evening, the water pump, the shower pump all running the batteries down. You then come to raise the anchor to find (possibly) there is not enough juice to do so.

This is why the windlass is wired to the starter battery on Galadriel.

If you "only operate the windlass after starting the engine", most of the windlass current will come from the alternator anyway, so battery type doesn't really matter. Wiring it to the house batteries preserves the integrity of the separate starter battery; if the windlass is operated without the engine running, it won't affect the charge state of the starter battery at all.

 

[vyv_cox]

IMO the best set up is to have the windlass wired to the starter battery, you only operate the windlass after starting the engine. Why do it this way?

1. The engine starter battery is better matched to the type of current draw which the windlass will take.
2. Wiring to the house batteries could see you having to manually raise the anchor. Imagine you spend three nights at anchor in the summer, fridge on, playing some music in the evening, the water pump, the shower pump all running the batteries down. You then come to raise the anchor to find (possibly) there is not enough juice to do so.

This is why the windlass is wired to the starter battery on Galadriel.

There are good reasons why I don't.
1. My starter battery is a tiny AGM (too small really) so it doesn't match the current draw particularly well.
2. Your doomsday scenario doesn't happen with 125 watts of solar panel and 330 Ah of domestic battery. However, if it did I would switch my 1-2-both switch to 1, start the engine, then switch it to 2 to power the windlass.

 

[prv]

you only operate the windlass after starting the engine.

No I don't.

At least, I didn't on KS. If the anchorage wasn't constricted (and, admittedly, a few times when it was...) I would happily raise the anchor and sail away. Quite possibly I'll do this less often with a bigger boat, or rather my definition of "unconstricted" may change, but I certainly wouldn't rule it out completely.

1. The engine starter battery is better matched to the type of current draw which the windlass will take.

The OP quoted a draw of 25 amps. That's less than a tenth of even a small starter motor. I very much doubt any deep cycle battery would struggle with that. And a "leisure battery" is fine even for engine starting anyway.

Imagine you spend three nights at anchor in the summer, fridge on, playing some music in the evening, the water pump, the shower pump all running the batteries down. You then come to raise the anchor to find (possibly) there is not enough juice to do so.

Sounds like a good time to start the engine, then

This is why the windlass is wired to the starter battery on Galadriel.

On Ariam, like Kindred Spirit before her, the engine start battery is for starting the engine, and nothing else.

Obviously I'm not trying to tell you what to do on your boat, just explain why I prefer my way.

Pete

 

[duncan99210]

We use the domestic batteries to power the anchor winch. 35mm cables run to the chain locker from a relay box in the saloon. I have a wired remote fitted to a socket in the chain locker for emergency use and a cheapo wireless remote from ebay for daily use; make an enormous difference to the operation with no extraneous cables to get tangled up in things and I can do the whole thing single handed from the wheel if required.

 

[Sans Bateau]

There are good reasons why I don't.
1. My starter battery is a tiny AGM (too small really) so it doesn't match the current draw particularly well.
2. Your doomsday scenario doesn't happen with 125 watts of solar panel and 330 Ah of domestic battery. However, if it did I would switch my 1-2-both switch to 1, start the engine, then switch it to 2 to power the windlass.

Ah! Well we have a starter battery with something like 900CCA and 2 x 125ah domestics plus a 45 watt solar panel, and thats of little use most of the time.

 

[Sans Bateau]

Obviously I'm not trying to tell you what to do on your boat, just explain why I prefer my way.

Pete

Thats very good of you.

I missed the bit about 25amp draw. Our Lofrans draws up to 90amp. How many times could you retrieve 60 meters of 10mm chain and a 16kg anchor with a domestic battery before killing it?

Replying to another post, as for starting the engine before raising the anchor when using the domestic batteries, you may have to wait until the engine battery is first full charged before the split charge regulator starts to fill up the domestic bank.

 

[pvb]

Replying to another post, as for starting the engine before raising the anchor when using the domestic batteries, you may have to wait until the engine battery is first full charged before the split charge regulator starts to fill up the domestic bank.

I guess that when you say "split charge regulator", you're thinking of a VSR. The starter battery would almost always reach a high enough voltage to trigger a VSR within a few seconds of the engine starting - it only needs about 13.5 volts. Most people don't have VSRs, but have splitter diodes, in which case the alternator's charge is immediately available.

 

[prv]

you may have to wait until the engine battery is first full charged before the split charge regulator starts to fill up the domestic bank.

I wouldn't, because my alternator charges the service battery first, that being the one more in need of charging. Although I've never known the Smartbank relay not kick in immediately to charge the engine one at the same time; perhaps it would delay if I ever seriously flattened the service bank.

(This is the system as installed on KS; Ariam is still as-purchased, with I think a big hefty diode block. Will be rebuilding her system to suit my preferences ( /prejudices ) in due course.)

Pete

 

[prv]

I guess that when you say "split charge regulator", you're thinking of a VSR.

Not necessarily, Sterling do an "Alternator to battery charger" which takes current from the alternator, applies magic battery charging goodness to it (different voltages, anti-sulphation pulses, etc) and sends it out of two separate outputs to the two banks. I believe it operates as Galadriel describes, getting the engine battery up to "float" stage before it starts on the service one. But as you point out, that shouldn't take very long given how few amp-hours it takes to start a healthy engine.

Pete

 

[prv]

How many times could you retrieve 60 meters of 10mm chain and a 16kg anchor with a domestic battery before killing it?

Given the typical sizes, two or three times more than I could with an engine battery!

Pete

 

[pvb]

Not necessarily, Sterling do an "Alternator to battery charger" which takes current from the alternator, applies magic battery charging goodness to it (different voltages, anti-sulphation pulses, etc) and sends it out of two separate outputs to the two banks. I believe it operates as Galadriel describes, getting the engine battery up to "float" stage before it starts on the service one. But as you point out, that shouldn't take very long given how few amp-hours it takes to start a healthy engine.

It doesn't. The Sterling Alternator to Battery Charger has a straight connection (via a diode) to the start battery, so the start battery has immediate charging.