Best Way to Power a Windlass

[stormalong]

Originally Posted by Shenandoah52

@ stormalong, I think overall that was one the better responses to the OP's question. I did, however get a chuckle out of this line... "You are adding a heavy battery at the bow where you do not want more weight."

Since the weight of a bow battery is equivalent to 30' of 3/8" chain I can't imagine a thread where anyone would actively encourage boat owners to cut off 30' of their anchor chain because that 30' of chain is going to cause them problems at the bow.

Is that a stretch? Most definitely.

I have a bias toward the 'pro' side of this issue due to years of anchoring off the SoCal coast where I would regularly be anchoring in deep water several times in a single day. Pulling up an anchor from 150" depth multiple times in a day shaped my thinking. If one's boating habits only require the occasional anchor hoisting from shallow water than a bow battery is probably overkill.

Shenandoah52: I once did a calculation of how much weight the ground tackle and windlass added to the bow. IIRC it was about 600 pounds - too much already.. Your saying that you would raise your anchor from 150 feet multiple times a day is one of the reasons I would not put a battery forward. Once that battery gets partially discharged unless you have appropriately sized cable you are pulling with a weak battery. The issue with that forward battery is not just weight, it is momentum. In rough conditions one G of acceleration doubles the weight of the battery so it had better be very secure. If it breaks loose it is the proverbial loose cannon. If it is a FLA, as tho OP's other batteries are it could be an acid bath.

We will have to agree to disagree on this one. Best, Brian

[Jim Cate]

Shenandoah52, I'm a little surprised that a pro would advocate use of a gel battery in this application, unless the house batteries are also gel. The charging regimes are quite different, and charging a gel at FLA absorption voltages ain't a great idea.

And FWIW, here's another advocate of cabling to the house bank for the windlass. 16 years of full time cruising in this boat with Maxwell 1200/1500 VWC and 30 foot cable runs, no motor issues due to low voltage (plenty of dissimilar metal corrosion issues, though). We've never anchored in 150 feet, but plenty of 60 feet and a few 80s in our history, using 60 lb anchor and 10 mm chain.

Jim

[Shenandoah52]

Originally Posted by stormalong

Shenandoah52: I once did a calculation of how much weight the ground tackle and windlass added to the bow. IIRC it was about 600 pounds - too much already.. Your saying that you would raise your anchor from 150 feet multiple times a day is one of the reasons I would not put a battery forward. Once that battery gets partially discharged unless you have appropriately sized cable you are pulling with a weak battery. The issue with that forward battery is not just weight, it is momentum. In rough conditions one G of acceleration doubles the weight of the battery so it had better be very secure. If it breaks loose it is the proverbial loose cannon. If it is a FLA, as tho OP's other batteries are it could be an acid bath.

We will have to agree to disagree on this one. Best, Brian

Hi Brian, I hear what you are saying but what you are missing is my rode was a heavy Danforth with 30' of 3/8" chain attached to 3/4" three strand rope on a 28' boat. Hardly 600 pounds including the windlass.

Also, after pulling anchor the run would be a good hour to the next drop giving my charging system time to recover. Keep in mind my windlass was also coupled to 2 deep cycle batteries amidships.

Notice also I don't recommend acid batteries. And the draw required by the windlass is what it is and will use up 'X' amount of battery capacity regardless. Being able to draw power from an auxiliary battery that is complimentary to overall battery capacity is the reason I stated it is the preferred method for high-draw DC motors run off batteries. Rule of thumb being to use the shortest run of cable from the battery to the motor.

And if one is unable to properly secure a battery in a battery box to their boat, well, well, geez I have no words...

[Shenandoah52]

Originally Posted by Jim Cate

Shenandoah52, I'm a little surprised that a pro would advocate use of a gel battery in this application, unless the house batteries are also gel. The charging regimes are quite different, and charging a gel at FLA absorption voltages ain't a great idea.

And FWIW, here's another advocate of cabling to the house bank for the windlass. 16 years of full time cruising in this boat with Maxwell 1200/1500 VWC and 30 foot cable runs, no motor issues due to low voltage (plenty of dissimilar metal corrosion issues, though). We've never anchored in 150 feet, but plenty of 60 feet and a few 80s in our history, using 60 lb anchor and 10 mm chain.

Jim

Jim, you're dead right. I've been using Optima batteries since the turn of the century and it never even occurred to me I'm probably the odd man out on this one. Thank you for pointing that out. The entire boat battery world has probably changed so much over the years I'm WAY farther out of the loop than I thought

And I also realize I'm the odd man out on putting a battery next to a high-draw DC motor. I also realize the prevailing view is if it ain't broke don't fix it. My advocating that position is from seeing the difference it makes in real life at my home shop and on my service truck. I would never go back to having my winches NOT have a battery next to them.

Many thanks for that post.

[Disailor]

Engine is always running when weighing anchor just in case & to provide more juice to a start battery up at the base of the V-berth (battery box provides a step up to berth). #8 wire (same size as comes out of the windlass) runs from the battery to a remotely controlled relay & then to the windlass.


A switch at the helm energizes a continuous duty relay that connects the windlass bat to the engine start battery with #6 wire. An off road vehicle remote control unit ($12 online) operates the windlass.

[stormalong]

Originally Posted by Disailor

Engine is always running when weighing anchor just in case & to provide more juice to a start battery up at the base of the V-berth (battery box provides a step up to berth). #8 wire (same size as comes out of the windlass) runs from the battery to a remotely controlled relay & then to the windlass.

A switch at the helm energizes a continuous duty relay that connects the windlass bat to the engine start battery with #6 wire. An off road vehicle remote control unit ($12 online) operates the windlass.

What is the wattage rating of your windlass. #6 wire sounds incredibly light for most windlasses I have ever heard of.

[Disailor]

A switch at the helm energizes a continuous duty relay that connects the
windlass bat to the engine start battery with #6 wire... ---End Quote--- ...#6 wire sounds incredibly light for most windlasses I have ever heard
of.

To be clear: the #6 wire runs from the windlass battery to the engine
start battery for charging current current. The #6 wire size is from a
wire size chart for 3% drop for the length involved.
The #8 wire was used between the windlass & the fwd battery because that
is the size of the wire coming out of the windlass as well as the
appropriate size from the wire chart with a 3% drop

[stormalong]

Originally Posted by Disailor

A switch at the helm energizes a continuous duty relay that connects the
windlass bat to the engine start battery with #6 wire... ---End Quote--- ...#6 wire sounds incredibly light for most windlasses I have ever heard
of.

To be clear: the #6 wire runs from the windlass battery to the engine
start battery for charging current current. The #6 wire size is from a
wire size chart for 3% drop for the length involved.
The #8 wire was used between the windlass & the fwd battery because that
is the size of the wire coming out of the windlass as well as the
appropriate size from the wire chart with a 3% drop

This is exactly what is wrong with the idea of a forward battery. You expect that forward battery to supply all of the power to the windlass. The light wire from the engine start battery cannot assist when the forward battery gets depleted after repeated anchoring attempts. That #8 wire sticking out of the windlass is based on it being very short. Have you checked the amp carrying capacity of that wire for the round trip distance to your windlass battery. I asked you the wattage rating of your windlass and got the answer above. You did not answer the question I asked. If you have a very low power windlass then maybe you are OK but your response says to me that you don't know.

Also, how are you determining the amperage draw from your start battery to the windlass battery to get within the 3%? If that forward battery gets low what prevents a much heavier load on that #6 wire? Do you have that wire fused to prevent an overload from turning that wire into a heating element?

If you are closing a switch at the helm to join the two batteries how are you determining when the windlass battery had been recharged? Sounds to me as a way to routinely undercharge your windlass battery and maybe drain your start battery. Undercharging your windlass battery in a slow death. When it dies you will be raising your anchor manually and if you forget to open the charging circuit when you turn off the engine you may end up with a dead start battery. I hope you are not cruising with this setup.

[Q Xopa]

Originally Posted by stormalong

This is exactly what is wrong with the idea of a forward battery. You expect that forward battery to supply all of the power to the windlass. The light wire from the engine start battery cannot assist when the forward battery gets depleted after repeated anchoring attempts. That #8 wire sticking out of the windlass is based on it being very short. Have you checked the amp carrying capacity of that wire for the round trip distance to your windlass battery. I asked you the wattage rating of your windlass and got the answer above. You did not answer the question I asked. If you have a very low power windlass then maybe you are OK but your response says to me that you don't know.

Also, how are you determining the amperage draw from your start battery to the windlass battery to get within the 3%? If that forward battery gets low what prevents a much heavier load on that #6 wire? Do you have that wire fused to prevent an overload from turning that wire into a heating element?

If you are closing a switch at the helm to join the two batteries how are you determining when the windlass battery had been recharged? Sounds to me as a way to routinely undercharge your windlass battery and maybe drain your start battery. Undercharging your windlass battery in a slow death. When it dies you will be raising your anchor manually and if you forget to open the charging circuit when you turn off the engine you may end up with a dead start battery. I hope you are not cruising with this setup.

Not that Im arguing either way. I can see the merrits and drawbacks of both approaches.

My newly installed 1200W windlass (Nilsson V2200) manual recommends AWG 6 wire for the 24v version, which I have for an upto a 70ft cable run. My run is close to 70ft. It only needs to cater for 50A at 24V. But I have actually gone with AWG 4, which they say is good upto 140 ft cable run.

Also they are only aiming for a max 10% voltage drop which they think is acceptable.

My boat has got a Fwd windlass batt from the PO. I am mid refit, and thinking I wouldnt bother with it any more.

But I am considering an each way bet with perhaps having a couple of small no maint batts as well.

Im looking at which small dry cell batts might be good.

Just tossing around options.

[Jim Cate]

FWIW: If I were an engineer designing a motor for a 12 v windlass on a recreational boat, I think I would base the design on a loaded supply voltage of perhaps 10.5 v or so, not the nominal 12 v. I suspect that that is the case for most small boat windlasses, and explains why we have had success with long cable runs.

Jim

[Q Xopa]

Originally Posted by Jim Cate

FWIW: If I were an engineer designing a motor for a 12 v windlass on a recreational boat, I think I would base the design on a loaded supply voltage of perhaps 10.5 v or so, not the nominal 12 v. I suspect that that is the case for most small boat windlasses, and explains why we have had success with long cable runs.

Jim

Yes 12v windlasses are often a bit of an ask. Its a lot of Amps trying to get sent a long way, which is not always easy.

Even if the batt is Fwd, it still has to get charged from a long way back. Of course Fwd batts have additional issues to deal with too.

It doesnt take much to upset that supply needed.

24v with lower Amps required makes windlass installs easier.

Obviously not always practical though, particularly with smaller boats.

But my windlass has installation guidelines in the Manual. As Im pretty sure they all do. If you cant lay your hands on this, then I would email or phone the manufacturer. No need to design engineer this stuff as the manufacturer has already done it.

Im not very smart but even me, in my limited experience, I have looked at what they recommend and stuck to, or bettered, them. It all seems to work fine.

[Q Xopa]

Originally Posted by Jim Cate

FWIW: If I were an engineer designing a motor for a 12 v windlass on a recreational boat, I think I would base the design on a loaded supply voltage of perhaps 10.5 v or so, not the nominal 12 v. I suspect that that is the case for most small boat windlasses, and explains why we have had success with long cable runs.

Jim

Reading your post again, I think you are saying you 'over spec' your cables?

That sounds good to me. Obviously a bit costlier upfront but can reduce headaches down the line.

[Sailor 99]

Originally Posted by stormalong

This is exactly what is wrong with the idea of a forward battery. You expect that forward battery to supply all of the power to the windlass. The light wire from the engine start battery cannot assist when the forward battery gets depleted after repeated anchoring attempts. That #8 wire sticking out of the windlass is based on it being very short. Have you checked the amp carrying capacity of that wire for the round trip distance to your windlass battery. I asked you the wattage rating of your windlass and got the answer above. You did not answer the question I asked. If you have a very low power windlass then maybe you are OK but your response says to me that you don't know.

Also, how are you determining the amperage draw from your start battery to the windlass battery to get within the 3%? If that forward battery gets low what prevents a much heavier load on that #6 wire? Do you have that wire fused to prevent an overload from turning that wire into a heating element?

If you are closing a switch at the helm to join the two batteries how are you determining when the windlass battery had been recharged? Sounds to me as a way to routinely undercharge your windlass battery and maybe drain your start battery. Undercharging your windlass battery in a slow death. When it dies you will be raising your anchor manually and if you forget to open the charging circuit when you turn off the engine you may end up with a dead start battery. I hope you are not cruising with this setup.

@Disailor ^^^^^^^^^^ This... 100%



You don't tell us the voltage or wattage of your motor but number 8 wire to windlass from the forward battery is simply not good unless it is right beside it and that seems unlikely. A battery 5 ft away needs number 6 wire.



When installing a windlass you have a choice. You can pay for the wire up front or you can pay for the wire each time you rebuild the motor. The damage to the motor is cumulative. Each time you over heat the motor it takes a little more life out of it.



When calculating wire size the distance is the round trip distance from the battery, not one way.

[sailingharry]

As has been said repeatdly, your symptoms with the chart plotter are NOT related to the wiring to the windlass. They are either with the battery (likely) or the wiring to the chart plotter (not likely -- a 2A draw will not usually result in measurable voltage drop).


However, you've also gotten a whole bunch of answers on how to solve the problem you don't have (wiring to the windlass).


On my 1998 Saga 43, a fairly high quality build of a Bob Perry design, the factory install is 1/0 wire (welding cable, in fact), driving a Maxwell 1700. This works flawlessly, and has for 20 years. My father's 40' motor sailor has both a windlass and a thruster running directly off cables as well (no idea of size). A battery forward is a common installation, but is in no way a mandatory solution or the only way to do it. Your boat is 30 years old and has been working fine this way -- don't fix a problem you don't have!


Oh, and there is another myth repeated here. DC is different from AC. In AC with rotating machinery (only rotating machinery -- not resistive loads like light bulbs, stoves, etc), the speed (and therefore the power demand) is set by the frequency (all synchronous motors run at a multiple of frequency, normally 1/2, or 1800 RPM, but some rotate at 1 revolution per cycle or 3600 RPM) . As voltage drops, current increases to maintain the same power. In DC the speed is not fixed (compare the cranking speed of an engine with a nearly dead battery vs one with a freshly charged battery). As voltage drops, speed drops, power drops -- and current DROPS! Lightbulbs and motors do NOT draw more current as voltage goes down. Motors might run longer (if the windlass speed drops, it takes longer to pull the anchor).



Harry

[sailingharry]

Originally Posted by Jim Cate

FWIW: If I were an engineer designing a motor for a 12 v windlass on a recreational boat, I think I would base the design on a loaded supply voltage of perhaps 10.5 v or so, not the nominal 12 v. I suspect that that is the case for most small boat windlasses, and explains why we have had success with long cable runs.

Jim

Jim,


You are spot on. While windlasses aren't up front about it, I think they do as you suggest. Thrusters are more specific, providing rated power at stated voltages, typically around 9.5V. They know you aren't going to get 12+ out of the battery at that current, and they know you can't realistically limit drop to 3%.


Harry