Best type of battery for anchor windlass?

[Paddy Layback]

I'm very grateful for all the helpful replies!
Plenty of planning required..

To add a new slant: I went to the boat show this morning, to hopefully get a discount on a windlass, (which they did, hurrah!)
andI asked the salesman about choice of batteries, and he said, just use ordinary truck batteries, with a big CCA rating!
Obviously they are cheap, but I will probly get sealed batteries with a decent CCA rating, (I don't like H and O fumes wafting about really, nor want to mess about with distilled water, specific gravity testers and all that palava)

They will be paralleled up with the house battery, assuming I can get the same type of battery, with isolator switches to isolate the windlass batteries from the house batts if I want, and using big fat cables from forward to aft.

 

[pvb]

They will be paralleled up with the house battery, assuming I can get the same type of battery, with isolator switches to isolate the windlass batteries from the house batts if I want, and using big fat cables from forward to aft.

Why not just use the big fat cables to power the windlass? Either save the money you would have spent on the batteries, extra fuse, switches, etc, or add the extra batteries to your house bank.

 

[Paddy Layback]

Why not just use the big fat cables to power the windlass? Either save the money you would have spent on the batteries, extra fuse, switches, etc, or add the extra batteries to your house bank.

Hi, the reason is that my 1 house battery, and my 1 engine battery, are just 80 AH each! They are near the companionway ladder. Access isn't brilliant but it's ok.

Despite being a very heavy boat, she doesn't have much room at the back to expand the existing battery banks by 200 AH (-ish).

Whereas there is plenty of room under the forepeak berths, with great access.
( And she floats a touch down by the stern at the moment.)

Your comments are much appreciated PD.

 

[geem]

Hi, the reason is that my 1 house battery, and my 1 engine battery, are just 80 AH each! They are near the companionway ladder. Access isn't brilliant but it's ok.

Despite being a very heavy boat, she doesn't have much room at the back to expand the existing battery banks by 200 AH (-ish).

Whereas there is plenty of room under the forepeak berths, with great access.
( And she floats a touch down by the stern at the moment.)

Your comments are much appreciated PD.

What!! 80 amp hr house battery!! We are 44ft live aboard with 900! Pretty normal when we speak to our cruising friends. What kind of boat has space for such a tiny house battery?

 

[pvb]

What!! 80 amp hr house battery!!

Have to agree that's unacceptably tiny in today's world. I'd be spending money on more house batteries as a first priority. There's always space - in my last boat I had 7 batteries lurking in fairly inaccessible underbunk lockers.

 

[Paddy Layback]

Well I've just worked around it by being miserly, never had any problems, all my lights are LED, my trusty 1970's Grundig portable does for music, and I have a head torch. I would never want 900 AH, what on earth for?

Plus, all those amp-hours need putting back in somehow, I find it simpler not to gobble them up in the first place!

The windlass batts could double up as house at certain times, eg up a river, on a buoy for a day or two(no need to get the anchor up, definitely motoring a bit after departure).

 

[geem]

Well I've just worked around it by being miserly, never had any problems, all my lights are LED, my trusty 1970's Grundig portable does for music, and I have a head torch. I would never want 900 AH, what on earth for?

Plus, all those amp-hours need putting back in somehow, I find it simpler not to gobble them up in the first place!

The windlass batts could double up as house at certain times, eg up a river, on a buoy for a day or two(no need to get the anchor up, definitely motoring a bit after departure).

We are liveaboards. A different life to yours but even weekend sailing I couldnt imagine 80 amps. Autopilot, nav lights, instruments, chart plotter. Your battery would last about 5 mins on my boat......

 

[Paddy Layback]

We are liveaboards. A different life to yours but even weekend sailing I couldnt imagine 80 amps. Autopilot, nav lights, instruments, chart plotter. Your battery would last about 5 mins on my boat......

I also live aboard . 2 years on this boat, 3 on my previous one, (although I tend to find a cheap marina for the coldest months of the year)
No plotter, no fridge, no autopilot...but wind vane steering, LED lights, 1 GPS, echo sounder.

 

[Chris_Robb]

Thanks for all the answers above, there are surely some fancy batteries available these days!

To GHA: That's a good point you make there, I was mulling over using fat cables anyway, even with the batteries forward. (There isn't room for them aft really).

Using cables capable of carrying starter motor size currents the length of the boat would enable me to start the propulsion engine (Volvo 36) with the windlass batteries, which might come in handy one day..as Sandy above points out..

One complication, of course, is charging different types of battery off the same alternator, some hard thinking/research to be done!

I have a 2005 AGM battery still working quite happily running both the Bow Thruster (little used) and the anchor winch -(1200 watt). I am amazed that the battery is still working after 11 years.

Rather than run off my domestic or engine battery, my engine battery is linked to a Sterling Battery to Battery charger which then goes down tahre thinner cables to the bow battery - but they are still pretty large cables. This system works a treat and has been in since 2008 as the boat originally had only a dedicated mains charger for the bow battery.

Ring Sterling and chat the problem through - even down to wire size.

 

[Paddy Layback]

I have a 2005 AGM battery still working quite happily running both the Bow Thruster (little used) and the anchor winch -(1200 watt). I am amazed that the battery is still working after 11 years.

Rather than run off my domestic or engine battery, my engine battery is linked to a Sterling Battery to Battery charger which then goes down tahre thinner cables to the bow battery - but they are still pretty large cables. This system works a treat and has been in since 2008 as the boat originally had only a dedicated mains charger for the bow battery.

Ring Sterling and chat the problem through - even down to wire size.

Hello that's very interesting, I will definitely ring them, thanks!

 

[pvb]

Hello that's very interesting, I will definitely ring them, thanks!

That's the same sort of system I described in post 20. But as the battery-to-battery charger costs £200-300, you might as well just install hefty cables, which would also allow you to use windlass batteries as part of your house bank.

 

[lw395]

If you go the fat cable route, the alternator will be able to contribute more to the windlass.
The windlass will only pull full power when the anchor is stuck in. Once the anchor is free, it will draw less power.
Likewise lowering, the alternator will provide a lot of the current. So the battery will need a lot less recharging.
But a battery with high cca close to the windlass will provide the surge current and near-stall current, limiting the draw down the cables.

It does need careful thought. It's more demanding than starter motors because windlasses get used for longer bursts, so the cables etc can heat up more.
It's good to have some cable resistance to prevent the whole surge going on the alternator. Particularly if you have a small alternator.
One subtlety is that as the bow battery gets old, the alternator and long cables get a harder life.
Thinner cables can be simpler, they will drop enough volts that the bow battery has to do more of the work. If they are somehow current limited to a safe value all is well and good.
Medium cables which pass enough current but have enough voltage drop to get really hot can be the worst option.
It's worth getting the numbers together and working out the voltage drops etc IMHO.

 

[Paddy Layback]

If you go the fat cable route, the alternator will be able to contribute more to the windlass.
The windlass will only pull full power when the anchor is stuck in. Once the anchor is free, it will draw less power.
Likewise lowering, the alternator will provide a lot of the current. So the battery will need a lot less recharging.
But a battery with high cca close to the windlass will provide the surge current and near-stall current, limiting the draw down the cables.

It does need careful thought. It's more demanding than starter motors because windlasses get used for longer bursts, so the cables etc can heat up more.
It's good to have some cable resistance to prevent the whole surge going on the alternator. Particularly if you have a small alternator.
One subtlety is that as the bow battery gets old, the alternator and long cables get a harder life.
Thinner cables can be simpler, they will drop enough volts that the bow battery has to do more of the work. If they are somehow current limited to a safe value all is well and good.
Medium cables which pass enough current but have enough voltage drop to get really hot can be the worst option.
It's worth getting the numbers together and working out the voltage drops etc IMHO.

Thanks for your viewpoint. I will have switches on the fat cables running forward, so I can isolate them from the alternator and the house battery if I want.
Because:
.. being able to get the anchor up without involving the alternator or house battery, and with the engine not running (it might be U/S), is essential to my way of thinking.

In my humble and personal opinion, and being in the lucky position to design and (mostly) install my own system, the very idea of being forced to run the engine to get the anchor up is a load of codswallop...