Anchor Windlass Battery Question

[ctva]

I am considering replacing three 85ah lead acid domestic batteries with 2 100ah lithiums (proper type) which will be charged off a combined B-B with MPPT solar input (Renogy 30AH model) retaining one lead acid engine battery. I currently have a Sterling Procharge Ultra which I will set to a lithium profile and charge the domestic bank from that. Not sure if the lead acid will be ok but I can sort that later if needed.

The question is, what would be the best way to charge a single lithium battery at the bow for the windlass, approx 8m from the main batteries? Is there a 2 bank B-B option?

Any thoughts would be welcome.

Thanks

Chris

 

[PaulRainbow]

Fitting a lithium battery at the bow for the windlass would be mad, fit an AGM. What is there now and how is it charged ?

 

[Frayed Knot]

Paul’s never one to beat about the bush, is he?
I asked a similar question a while back & got some really helpful advice - plus a bit that wasn’t. You might find it useful to take a look. LiFePo Query
All things considered, it pretty much could be summed up by Paul’s answer above

 

[ctva]

Fitting a lithium battery at the bow for the windlass would be mad, fit an AGM. What is there now and how is it charged ?

Nothing there at the moment, hence the question. Why would a lithium be mad for the windlass, cost?, suitability?, or something else?

So given the setup above, what would you recommend?

 

[vyv_cox]

Why have a dedicated battery for a windlass? For a thruster maybe but no need for a windlass. Just run heavy cables forward for it. Mine has been like this for 20 years at rather further distance.

 

[JOHNPEET]

Sometimes there a multiple acceptable solutions to a problem which may only be differentiated by the preferences or opinions of the boat owner!
I have three battery banks, all of which are AGM:

1. house bank - 6 x 140AH configured for 24v
2. dedicated engine start battery servicing both engines - 2 x 160AH configured for 24v
3. dedicated windlass battery - 2 x 100AH configured for 24v

I also have a single 75AH for starting the generator.

The three main banks are charged either by the main engine alternators via 2 x Victron Argofet battery isolators or by a Victron 60 amp 3 way charger from shore power or the generator.

For my usage - the system works well.

Reasons for this approach - Redundancy mainly! I have change over switches on the battery supplies which allow me to start the main engines from their dedicated start battery or the house bank. Equally, I can operate the windlass from its dedicated battery, or the house bank.
Without a dedicated windlass battery, the windlass’s power requirements would have to be taken from the engine start or house bank - a personal choice to make - I chose to go separate.
I believe this to be a sound approach but others may choose to take a different approach.

 

[Tranona]

I am considering replacing three 85ah lead acid domestic batteries with 2 100ah lithiums (proper type) which will be charged off a combined B-B with MPPT solar input (Renogy 30AH model) retaining one lead acid engine battery. I currently have a Sterling Procharge Ultra which I will set to a lithium profile and charge the domestic bank from that. Not sure if the lead acid will be ok but I can sort that later if needed.

The question is, what would be the best way to charge a single lithium battery at the bow for the windlass, approx 8m from the main batteries? Is there a 2 bank B-B option?

Any thoughts would be welcome.

Thanks

Chris

Does your windlass currently run from your house bank? Presumably when you install your lithium house bank you will keep the dedicated engine start and charge that directly from the alternator then a B2B from the start battery to the house bank (plus from solar). In that case your windlass will run from the new house bank using the existing wiring.

Lithium is not recommended for bow thrusters and to a lesser extent windlasses because those items require a high amp load for short periods which lithium does not like and there is no benefit from the deep discharge properties. Best batteries if dedicated to the thruster or windlass is LA, probably AGM with a high CCA. The advantage of a bow battery charged by a B2B from the start is the smaller cable size, less important for a windlass, but if you have both windlass and thruster as I have a bow battery (in my case a 110aH Numax leisure) is arguably better.

 

[ctva]

Does your windlass currently run from your house bank? Presumably when you install your lithium house bank you will keep the dedicated engine start and charge that directly from the alternator then a B2B from the start battery to the house bank (plus from solar). In that case your windlass will run from the new house bank using the existing wiring.

Lithium is not recommended for bow thrusters and to a lesser extent windlasses because those items require a high amp load for short periods which lithium does not like and there is no benefit from the deep discharge properties. Best batteries if dedicated to the thruster or windlass is LA, probably AGM with a high CCA. The advantage of a bow battery charged by a B2B from the start is the smaller cable size, less important for a windlass, but if you have both windlass and thruster as I have a bow battery (in my case a 110aH Numax leisure) is arguably better.

Manual windlass at the moment which is why I'm looking at the options. I was looking at options for a battery near the bow as the 35mm cable is not cheap. Could I run two B2B charges off the one alternator, one to the Lithium house bank and another to a windlass battery? Or is this just too complex?

 

[PaulRainbow]

Manual windlass at the moment which is why I'm looking at the options. I was looking at options for a battery near the bow as the 35mm cable is not cheap. Could I run two B2B charges off the one alternator, one to the Lithium house bank and another to a windlass battery? Or is this just too complex?

35mm cable from the engine battery or you can run 2 BtoB chargers. Simple cables are, erm, simple. A second BtoB isn't cheap and you'll still need to run cables to the bow. Finally, with 35mm cables you'll get some decent current from the engine battery and the alternator, which will help the windlass.

KISS

 

[QBhoy]

I’d think it better or more conventional to have the windlass just ran off one of the domestic batteries or similar. Or at least ran from a battery back in the engine bay at least. Most boats wouldn’t likely have a dedicated battery up forward for just a windlass in mind. Or even a dedicated battery anywhere for just this in mind.
Much easier to run cables and the required ancillary items, of the required rating towards the bow, rather than have an isolated battery up there where a battery might not be too happy.
Best of luck.

 

[ctva]

Thanks for all the input.

So, if I'm just going to run a 35mm cable to the bow, which wopuld be better to run it from, the 200ah Lithium domestic or 86ah lead acid engine battery?

 

[Neeves]

Sorry to be repetitive, with apologies to NormanS

If you are changing your windlass now is the time to look at your chain. Down size you chain (will your chain need to be regalvanised 'soon'), you can buy a windlass with a smaller motor, the smaller motor will need less power, so smaller electric cables. The smaller power demand will make running the windlass off the house bank more sensible (or easier) than a separate windlass battery. The smaller link size will remove weight from the bow and reduce the amount of space used in the chain/anchor locker. You can have a longer chain of smaller size link and still save weight and space (depends on how much longer).

You may not notice but your yacht will perform better with the lighter chain in the bow.

You will need a decent snubber, but they cost peanuts.

I have a series of articles on smaller chain and snubbers - if you have missed my science lessons

I note Paul is saying run the windlass off the engine battery. To me I like to keep the engine battery - for the engine. But it might depend on the size of your engine battery and the sizes of your ground tackle. We had small chain, 6mm and aluminium anchors, 8kg each anchor. If the windlass failed - for any reason - I could retrieve by hand. I cannot start the engine by hand and I cannot use the autopilot nor bilge pumps by hand. For us running the windlass off the house bank, which was 400amps, seemed sensible. Keeping a dedicated battery for the engine seemed sensible - with the fall back of being able to switch engine to the house bank (which in 20 years we never had to do). I don't think it relevant but our house bank was 4m from the windlass.

Our practice was to always have the engine(s) running in neutral (catamaran) when retrieving the anchor.

Jonathan

 

[QBhoy]

Thanks for all the input.

So, if I'm just going to run a 35mm cable to the bow, which wopuld be better to run it from, the 200ah Lithium domestic or 86ah lead acid engine battery?

Personally I’d keep essential items like that on the engine battery. But I’d also add that I’d upgrade that battery to a dual purpose high cca marine battery. You can get the likes of a 110ah dual battery with some serious cca ratings these days. Along the lines of 800cca or more. But also capable of other duties too. Keep the domestic leisure supply side for non essential items around the boat. Nav lights, windlass, navigation instruments and engine duties ideally from their own dedicated and strong supply source battery. Peace of mind should follow.
My thoughts at least.

 

[QBhoy]

Manual windlass at the moment which is why I'm looking at the options. I was looking at options for a battery near the bow as the 35mm cable is not cheap. Could I run two B2B charges off the one alternator, one to the Lithium house bank and another to a windlass battery? Or is this just too complex?

Also, I’d suggest that with regards to the cable rating, to perhaps be aware of the expected impact/drop in available power values berween the source battery back aft…and the delivered power up the bow at the windlass itself. So despite a 35mm cable likely being able to rate at 240amp. Should the windlass demand anything close to that, you’ll be touch and go. Unlikely she’ll demand anything as much perhaps, but worth thinking about the power drop effect you’ll almost certainly encounter. You’ll likely want or require a relay and circuit breaker in line too. Should help things greatly.
All the best.

 

[PaulRainbow]

Thanks for all the input.

So, if I'm just going to run a 35mm cable to the bow, which wopuld be better to run it from, the 200ah Lithium domestic or 86ah lead acid engine battery?

Engine battery, no question. If you can fit a bigger one, do so. Fit the thermal circuit breaker recommended by the windlass manufacturer close to the engine battery.

 

[PaulRainbow]

Personally I’d keep essential items like that on the engine battery. But I’d also add that I’d upgrade that battery to a dual purpose high cca marine battery. You can get the likes of a 110ah dual battery with some serious cca ratings these days. Along the lines of 800cca or more. But also capable of other duties too.

Why would you do that for an engine battery ?

An engine battery (and the windlass) just want high CCA, they get that from cranking batteries, no need for so called dual purpose and it doesn't need to be capable of other duties, it's the engine battery.

 

[QBhoy]

Why would you do that for an engine battery ?

An engine battery (and the windlass) just want high CCA, they get that from cranking batteries, no need for so called dual purpose and it doesn't need to be capable of other duties, it's the engine battery.

Just making it simple. Most available marine batteries of that size, are commonly labelled as dual purpose. Why wouldn’t you ? Mostly, generally speaking, a 110ah battery like this, will have a greater cca than the like for like 85ah version. A good 85ah starter battery will do well for 650-700 cca id suspect. You’ll see more from a 110ah starter capable battery.
That’s all.

 

[PaulRainbow]

Just making it simple. Most available marine batteries of that size, are commonly labelled as dual purpose. Why wouldn’t you ? Mostly, generally speaking, a 110ah battery like this, will have a greater cca than the like for like 85ah version. A good 85ah starter battery will do well for 650-700 cca id suspect. You’ll see more from a 110ah starter capable battery.
That’s all.

The reason you'll see more CCA isn't because of the "marine" or "dual purpose" labels, which are nonsense, it's because it's a bigger battery. For engine starting, all you need is a starter battery, the clue is in the name

If one wanted to spend a little more than a standard starter battery costs, an AGM battery would be a good investment, which i suggested in post #2

 

[QBhoy]

The reason you'll see more CCA isn't because of the "marine" or "dual purpose" labels, which are nonsense, it's because it's a bigger battery. For engine starting, all you need is a starter battery, the clue is in the name

If one wanted to spend a little more than a standard starter battery costs, an AGM battery would be a good investment, which i suggested in post #2

Well aware of that. Making things simple just. You shouldn’t get yourself so flustered by silly things. Some might even think you out to create argument even . It’s all good. Everyone else knew what my point was, without needless sillyness.

 

[PaulRainbow]

Well aware of that. Making things simple just. You shouldn’t get yourself so flustered by silly things. Some might even think you out to create argument even . It’s all good. Everyone else knew what my point was, without needless sillyness.

I'm not flustered and the needless sillyness is you, starter batteries should be starter batteries, that's simple enough.