Best Way to Power a Windlass

[sailcrazy]

We have a 2017 1200w Maxwell VW2500 windlass (100 amp) installed on our 30-yr old monohull. 12v power is supplied via a pair of manufacturer-installed heavy cables (+ & -), each approx 30' long; power comes from our house bank, 6 3-yr old Trojan T-105s, initially rated at 675 amphrs. Ever since I installed the new windlass, however, we've been getting a "low voltage" alarm on our chartplotter when we bring the anchor up. There are no other signs of battery or power problems, except during windlass operation. It's possible the builder used welding cable (vs tinned wire) and the cables are feeling the effects of age and corrosion(?). One option is to replace both cables. Another option is to install a dedicated windlass battery in the bow. But how big a battery(s) should I install, to ensure the windlass will have the power it needs to bring the 25kgm Rocna up? And what's the best way to recharge that battery(s)? Currently we use a Balmar Duo-Charge to recharge the start battery, so another Duo-Charge would work? Or a Mastervolt Magic 12/12? Or??? Or...should I be looking somewhere else to resolve the issue? Looking for advice and suggestions.

[model 10]

I installed a G-27 as far fwd in the main cabin as I could. So it's maybe 12' away from the windlass, so 25' of cable. I used the biggest stuff I could find, 00 I think. It's a 1000w windlass and I abuse the hell out of it and there has never been an electrical problem. I wired that batt into the entire house batt system with #4 cable.

[Jammer]

Originally Posted by sailcrazy

Or...should I be looking somewhere else to resolve the issue? Looking for advice and suggestions.

Measure the battery voltage while the windlass is operating. If it is reasonable (at least 12.0 volts), then maybe your chartplotter is too sensitive. It may be possible to disable the low battery warning, or set it to a lower voltage, in the setup menus. The battery voltage under heavy load will gradually drop with age even if the batteries are still good.



Check the battery terminals and large cable terminations with an IR thermometer immediately after you've raised the anchor. If any are warmer then you've found at least part of your problem. (Disassemble, then either clean and tighten or replace as appropriate)


If you still haven't found the problem disconnect and check each battery with a load tester.


https://www.amazon.com/OTC-3180-Batt...1PMC9652WBGRNF


The batteries should be closely matched (within 0.2 volts) and, if fully charged, test to at least 12.5 volts.


If the batteries are mismatched then you have one or more bad batteries or bad connections. You can check specific gravity of each cell in the doubtful battery, and if the cells are mismatched then that would tend to confirm that the battery is shot. If the specific gravity is more or less the same in each cell then you might have a connection problem in the cables for that battery.



If all the batteries test low with the load tester, then either you need new batteries or your charging system isn't charging them enough.


I don't think you'll find anything wrong in the windlass or its wiring

[Simi 60]

I was always of the belief that you use start batts with engine running so alt provides input.
Our engine and starts are at the front half of vessel, house bank at back half so this works for us

[CarlF]

After a night at anchor are your house batteries showing about the same voltage as you remember when they were new? If yes, then they are not likely to be the culprit.

Before the expense and challenges of new components -

Clean and retighten the cables - because it’s always a good idea.

Does the chartplotter crash or just beep momentarily? If just beep, maybe live with it? T105’s aren’t going to be bothered by a few minutes of low voltage.

Drive forward on the chain and then fast idle the engine in neutral while hauling to get the alternator to contribute more.

If this all fails, maybe try connecting the windlass cables to the start battery. Alway start the engine before operating the windlass to be sure the start battery isn’t drained. The chartplotter will then not see a low voltage as it’s still connected to the house bank.

[stormalong]

Sallcrazy: Is your engine running when you have this issue? Is it running fast enough for the alternator to be putting out a good amount of current?

Try a faster idle on your engine when pulling in the chain.

I have a very similar setup as you. VWC1500, six t-105s in series parallel, 44 ft boat so much longer were run.. I don't have a chartplotter - I use an Intel NUC running OPENCPN but have never noticed any issue when lifting the anchor.

Another thing you could check is to compare the voltage at the battery and the voltage at the chartplotter. They should be very close- within .2 volts. If there is a significant difference there may be an issue with the chart plotter wiring.

[Sailor 99]

Originally Posted by sailcrazy

12v power is supplied via a pair of manufacturer-installed heavy cables (+ & -), each approx 30' long;

DC power is different from AC AC small wires, no problem. DC small wires big problem.

You want to run a 100 amp windlass from 30 ft away. That is a lot of power and you need big wires.

Run that through blue seas wire sized chart ( phone app available) and you will see you need 4/0 wire for that. Don't think that it is a straight 30 ft. The wire may have to snake. You also have to take total length which is there and back so its 60 ft + 2x the snaking.

I could be wrong but I bet no way that they put 4/0 cable through the boat. But to verify measure. You can find the diameter of that on line.

On my 50, the batterries were at the back they ran 45 ft of wire one way up to the front and used #2. I moved the batteries within 18 ft, need 23 ft to get there and am using 3/0.



Check your plotter and see what the rating is and make sure you have big enough wire for that. Over sizing to the is not a bad thing. Low voltage causes things to burn out.


You can go cheap and undersize and burn out the motor, or you can go with what the charts say and have a long live on that motor. Or you can go bigger... 3% voltage drop is the limit for a good boat electrical.


Don't buy your wire from a marine store. Buy your wire from a wire supply company. They have this wire too. 1/2 the price or less of marine store for exactly the same wire.


As for non-marine grade cable, I have never had problems with that in a boat. In the 80's Beneteau and most of the other builders did not use tinned wire. My beni is all bare wire except what I put in and its all in top condition. Outside now is a different animal. Don't even think of wires up the mast or to running lights or anything else not using tinned wire. Even the tinned wire gets eaten by the salt.

[Shenandoah52]

Originally Posted by sailcrazy

Another option is to install a dedicated windlass battery in the bow.

If you have room and are capable of wiring it correctly a dedicated battery will do wonders for your situation. On a huge amp draw like the one your windlass produces you want the 12 volt source as close to the dc motor as possible. This is true across the board. Even on my service truck I have a dedicated battery as close to the service crane as I can get. Even with the diesel running and the two start batteries providing power to the crane and winch the 25' distance from the engine compartment to the crane requires a dedicated battery to the crane and winch. This also helps the dc motors on the crane to last longer the same way it will help your windlass motor.

You should be able to see a reduction in the temperature of the motor after a heavy use just using your hand held against the motor casing if the battery is close to the motor.

[Uncle Bob]

Originally Posted by Simi 60

I was always of the belief that you use start batts with engine running so alt provides input.
Our engine and starts are at the front half of vessel, house bank at back half so this works for us

+1.

[Adelie]

2 hands, 2 arms, 1 back.

[sailcrazy]

Thanks for the input. Yes, we do run the engine, but (per your advice) we will start reving it up some.......it's typically been at idle so far. The eng alternator (stock, 85 amp internally regulated) is connected directly to the house bank, so any power it generates goes directly to the house bank. FWIW, we recharge the start batt with a Balmar Duo-Charge coming off the house bank, but the windlass is wired to the house bank. We've set the chartplotter V alarm at 10.8v, about as low as it can go. I did note, when I installed the new windlass. the existing old cables seemed stiff to me....they were not real flexible. But when I trimmed the ends, exposed new wire, and attached new terminals for the new installation, I found no evidence of corrosion.....but they were stiff and didn't want to bend! The West Marine price for new cables is +$350, while a new Duo-Charge ($240) + battery ($100) + batt box($40) is about equal $$. For those that have a sep, dedicated windlass battery, what size do you use, and how do you recharge it? Will it support dropping the anchor, the pulling it and resetting it, and pulling it back a second time? Thanks again for the insight. PS...I did not think of using the IR thermometer on the windlass terminals to check for elevated temps....I will try that when we get back to Puerto Rico and the boat in a couple of months.

[Sailor 99]

Originally Posted by sailcrazy

we will start reving it up some.

Anything is better than nothing but if you can get a smart regulator for it and then convert the alternator to externally regulated.

I did that to 2 ikra alternators.

The power out put difference is phenomenal

Originally Posted by sailcrazy

I did note, when I installed the new windlass. the existing old cables seemed stiff to me....they were not real flexible. But when I trimmed the ends, exposed new wire, and attached new terminals for the new installation, I found no evidence of corrosion.....but they were stiff and didn't want to bend!

Cheap plastic insulation?

Originally Posted by sailcrazy

The West Marine price for new cables is +$350, while a new Duo-Charge ($240) + battery ($100) + batt box($40) is about equal $$.

For those that have a sep, dedicated windlass battery, what size do you use, and how do you recharge it?

If you changing the cable shop around. West marine is the last place you want to buy it.


If you put a deep cycle battery up there you can just connected it with the other system using the existing cables in a parallel hook up.

Its dedicated just by the fact that its close but has the other batteries to draw on for better life.

The wear and tear on the battery will be different from the house because you can't wire them ideally but it would work.

I would not be buying a separate charger. Some how you have to charge this battery when your under way. That means the alternator. KISS works good

You should be able to up and down the windlass all day. If not what you going to do when you can't get a hook the first or second time or you drag.

[Shenandoah52]

Adding to what others have said here, the size wire you want to use for the dedicated battery to windlass connection would the same thick wire size that is probably what you have right now. The dedicated battery connected in parallel along with your current system is what you are looking for.

Picture it this way... where the present heavy cables are attached to the windlass they will now be attached to the dedicated battery (+) to (+), (-) to (-), and the new heavy cable will run from the new battery to the windlass. The windlass switch still needs to be between the new battery and the windlass. If you have a foot-switch next to the windlass it will be an easier installation than if the windlass switch is at a remote location such as the helm. And please don't forget the fuse/circuit breaker.

The new battery serves as a reservoir of energy the windlass can tap into and is located where the demand meets the source so everything is more efficient. If your current batteries are hooked up to a charging system then the new dedicated battery wired in parallel with the older battery will allow the new battery to also maintain a charge.

But pay attention right here... I'm trying to give you a concept that allows you to understand how/why your heavy draw windlass motor is happier with a 12 volt source close to it. I may have left out important things YOUR system needs to accomplish the task. I don't know your system, so be good and sure you understand the concept before you do a DIY on this.

Case in point... When I bought my first boat in 1978 I was a little less knowledgeable about these things and I hired a professional golf cart mechanic to do some wiring on my boat. He wires golf carts for a living. He came down to the boat, installed two heavy-duty 6 volt batteries in series to give me 12 volts for my stuff to run on. I came back the next weekend and the entire wiring harness coming out of the bilge and going up to the flybridge was a solid fused mass of charred wire and burnt plastic. How my boat never burned to the waterline is a mystery to me. So let's be clear here... the amount of amps we are talking about here can be dangerous.

[smac999]

Bad cables going to the windlass woukd cause a low voltage at the windlass. Not the plotter. Don’t just replace the windlass cables. You need a voltmeter to track down where the drop is happening. It could be at battery, battery switch. Etc. But it’s not the windlass cable.

You do not need a windlass battery in the Front.

If you had a bow thruster drawing 500a which many do. Then a bow battery helps. But many boats do not and they work with out issues. Find and fix the problem. Don’t Add bandaids.

[stormalong]

When you put new terminals on the existing wire did you notice how thick the individual strands were?

When I installed my electric windlass tinned 2/0 wire from West Marine was $5 a foot - that was in 1991. I went to an electrical supply house and bought 2/0 cable for under $1 per foot. I needed 90 feet and was not going to give West Marine $450. The electrical supply cable was made up of 12 gauge strands and it is very very stiff. It was quite a job to install that but it is still in use today. The stiff wire only has to be dealt with once. Because it is not tinned extra caution was used attaching the lugs and sealing the ends. Thick strands are actually more resistant to corrosion from water intrusion in contrast to welding wire that is very fine strands that will corrode to dust very quickly if it gets wet.