Best Way to Power a Windlass

[stimpsonjcat]

A 'starter' battery near the windlass would likely solve the issue OP has. You aren't going to get current flow any farther upstream than necessary. If the close battery can supply enough power, the rest of the system will be unaffected.

[Icarus]

Originally Posted by 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.

I use a seperate heavy duty cranking battery on the bow, thats eliminates two heavy battery cables.
The battery gets charged with the engine start battery via a solenoid. Duo setup.
I use a simple battery swich.
Basically i have 4 x 6V house T 105
And 1 x 12V engine cranking batteries.
And 1 x 12V anchor battery located at the bow
Works really good.
I most of the time start the engine when I raise the anchor
By the way T 105s are deep cycle batteries
So for crancking power its better to use heavy car cranking battery.

You need to do a voltage drop test at the whinch when under load
That will tell you if the 2 supply cables are good or not.

[sailcrazy]

Thanks Icarus for the insight. What size is the starter batt in your bow, and just exactly how do you recharge it....I didn't understand your comment about the solenoid, duo setup, and simple batt switch. Could you explain it please? We currently are using 6 T-105s for house power, and have a size 27 start battery for engine and genset starting. We recharge the start battery via the genset alternator (very small) and a Balmar Duo-Charge from the house bank to the start battery. From what I'm reading in everyone's comments, I'm thinking my issue is likely a very substantial high current draw due to an increased resistance in the 30-yr old (likely) welding cables having some internal corrosion running from the DC distribution center forward some 30' to the windlass in the bow. The (normal) high amperage draw of the newer windlass, thru my high(er) resistance cables is just pulling my house bank down more than I realized. Replacing the hi-power cables, and/or installing a new power source very near the windlass seem like the likely best options.

[stormalong]

IMO the topic of using a start battery forward vs the house battery should be discussed.

A start battery is designed to proved a very large current very a very short time.

A golf cart battery, which many of us use as house batteries is designed to power a golf cart motor for a period of time - a much longer period than a start battery and not a light load.

Raising an anchor takes time. For example, IIRC my Maxwell VWC1500 with a 1200 watt motor pulls at 60 feet a minute. For my typical anchoring I use 100 feet of chain. So, the windlass is in use for about one hundred seconds. The house bank is comprised of six 6 volt batteries in series/parallel meaning that the current draw on one pair of batteries is one third of the total draw. An engine start battery is usually a single 12 volt battery meaning that the entire power draw is on that one battery for one hundred seconds. Starting my engine, after preheat which I always do takes about one second.

While engine start may draw 300 amps it is only for one second before the alternator starts putting power back into it. The house bank, if the engine was off while raising the anchor (which I do not do and I expect very few of us would do) would be drawing 33 amps per pair for the 100 seconds compared to the start battery which would be under a 100 amp load for that same interval.

Without doing the math, I think the house bank is much more suited to that prolonged power draw than the start battery.

So an engine start battery at the bow that is recharged at a slow rate through light wire has the worst combination of events. Power is drawn for a much longer interval than it is designed for and it is recharged much more slowly.

This is the thinking that I used when I chose not to have a battery forward but instead to use the house bank and 2/0 cable and a high output alternator also supplying power when raising anchor.

Comments?

[Apollo366]

I recently replaced my windlass wires (Cables) with new ones because the old cables were from 1984, undersized, wrong type of copper and not tinned.

I was an Electrician in the Navy long ago so understand E=IR very well, and since I was an IT guy/manager in my last career I also understand the increase in performance that all our newer "stuff" has over the older stuff.

I always run the engine at fast idle with BOTH bank of batts on when using the windlass, it just makes sense to give it the most current & capacity available to do its heavy work.

As pointed out above, easiest test is to use a digital volt meter to measure volts at the distribution panel or batt terminals, and note it before engaging the windlass with a load, then measure volts at the windlass terminals with the load on.

With engine running the panel volts (you have a digital VM on the panel, right?) should be 12.6+. under load the windlass volts should be 11+ as a minimum. Anything less than 10 Volts, clean, repair, replace as needed and all should be well.

I've also seen connecting a large 12V batt, like a starter batt used in auto shops, connected directly to the windlass to do this test.

Now the one thing I forgot is: is the windlass >10yrs old? Has the windlass had the bearings cleaned & greased lately <1yr)? If no, it might be the windlass vs wiring, but you said the wiring cable looked old & brittle, that's a sure sign they need replacing.

Hope this helps,

Apollo Wayne

[CarinaPDX]

A little back-of-envelope calculation:

My anchor chain is 300ft long. My windlass is specified at 100ft/min, so with all chain out (rare) it takes 3 minutes to lift it up. (Note: I stop frequently to knock down the chain pile and wait for the catenary to re-form.) 3 minutes is 1/20th of an hour (3min/60min). My windlass has a 60A breaker, so let's assume a 60A load. The amount of power removed from the battery is 1/20 times 60A for a whopping 3AH. With a 100AH battery that is just 3% of capacity, and that is assuming the alternator isn't charging the battery at the time.

Bottom line: the engine start battery is more than enough.

As mentioned earlier having more resistance in the wires between battery and motor (undersized or corroded) reduces the current flow in the loop, and hence draws down the battery less. However, the voltage across the motor is reduced because of the voltage drop over the resistive cable. For the OP's problem with the chartplotter the voltage at the battery is the issue so cable problems to the windlass are probably not the issue. If the problem is low windlass power then take a look at the wires.

Greg

[Adventure35]

I use a Milwaukee 28V cordless right angle drill. Works great...

[SVTatia]

Originally Posted by Adventure35

I use a Milwaukee 28V cordless right angle drill. Works great...

I think there is some misunderstanding here... taking a drill to the bow to raise an anchor? How do you attach it to the windlass?

[Adventure35]

Originally Posted by SVTatia

I think there is some misunderstanding here... taking a drill to the bow to raise an anchor? How do you attach it to the windlass?

I purchased a cranker bit for the drill. I switch the Maxwell windlass to manual mode and use the drill. Up comes the anchor at blazing speed. No gearbox, motor, and long cables in my system.
I will admit to not being a full time cruiser, and question the viability of the system under those conditions. I think the biggest drawback for cruising would be the storage of the drill. I have a neoprene cover for the drill to keep it relatively safe from the elements.

[capnorv]

Originally Posted by stormalong

Sailingharry, You started your post with: Oh, and there is another myth repeated here. DC is different from AC.

That is what prompted my reply.

You also wrote: As voltage drops, speed drops, power drops -- and current DROPS! That is not really accurate with motor loads. The current actually increases as the motor load increases.

I'm not sure we disagree either, other than terminology.

The idea of an AC windlass has merit except that the starting loads for AC motors is so much higher than running loads that the ability of an inverter to supply that load is questionable. This is also an issue for generators.

Good inverters take inrush into consideration. My little 3000 watt inverter actually has an inrush limit of 6500 watts for 10 seconds. I've been toying with the idea of supplementing my manual windless with an electric option for singlehanding in precarious conditions. No matter what you hear, I for one am envious when I see electric windlasses bringing in 250' of chain without raising a sweat. Does anyone know of 110vtac options?

[Frankly]

I have only worked on a couple of small boat windlass motors. Both were permanent magnet (vice field coil) DC motors. When a PM DC motor is running on lower than specified terminal voltage the motor slows down, the torque goes down, and it might even run a little cooler.


I haven't read every word of all the comments, but don't think anybody has mentioned the voltage drop due to internal battery resistance. Not insignificant depending on age, and chemistry.


I run 6 GC batteries, 4 midships, 2 in the bow (bilge) all electriclly connected series and parallel (fuses and switches). This bank provides for house loads, starts my Yanmar, runs the windlass and bow thruster. After 14 years with this configuration wouldn't consider any other arrangement.


Also like chocolate ice cream but not vanilla


Frankly

[Jim Cate]

I haven't read every word of all the comments, but don't think anybody has mentioned the voltage drop due to internal battery resistance. Not insignificant depending on age, and chemistry.

Good point! And that factor is why measuring the voltage at the motor under load does not really tell you much about the voltage drop in the cables. Rather, one needs to either simultaneously measure voltage at the motor and the battery and note the difference or actually measure the delta V between battery and motor under load. The latter takes some long leads for your DVM but is the more accurate measurement, eliminating the need for simultaneous measurement of varying voltages.

But let me add my voice to those saying that voltage drop in the cables ain't the cause for the MFD drop out... it's the drop in system voltage at the panel caused by t he drop in battery voltage from internal resistance and high load. Larger cables will make the windlass work better but not solve the problem he is posting about.

Jim

[capnorv]

I'm thinking of switching to a 120vt/ac windlass powered by a frequency drive. Totally out of character of the boat, but times they are a changing. Retirement will bring on longer cruises.

[Old fella]

Originally Posted by 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.

Hell some of these people like to sound technical , it's so easy, you have already cables running to the bow so like others have said cut the cables as forward as you can and link in another battery, I had this system in my boat for 20 years nab she was 58 ft long with the batteries right in the stern, worked perfectly , oh and by the way don't buy into the crap of using your house batteries, always use your crank batteries .reason, you pull into a bay and drop your anchor then turn your motor off, batteries now charged , you stay the night using your house batteries , in the morning they partly discharged, you start your motor and use your winch on fully charged crank batteries not half flat house batteries, not to mention as a rule deep cycle batts are made for lighter longer loads and crank batts are made for heavy short loads, oh and always use your boat to get the anchor off the bottom, it's all just that easy and without all the technical ********.

[sailah]

I have a total of ~65' run of 1/0AWG marine Ancor cable running from house bank (2x GC2) to windlass, which is a 1500W Lofrans unit. Reswaged new lugs when I redid a bunch of other cable. Pulls like a champ, engine running or not. Cable was there when I bought boat and is in good shape.

I debated putting windlass on engine start bank but I followed the excellent wiring schematic of MaineSail and it made sense to me. I listened to both camps of windlass on start vs house and decided to do it as he recommended.