Running a windlass off of inverter

[a64pilot]

I don’t think people understand what the voltage drop on a single small battery is, compared to a whole bank with a long wire run, I’d lay odds that the one small batteries voltage drop is greater. It seems they think there is no drop due to short wire run, which is incorrect.
It’s normal for an automobile to pull the battery voltage down to 10V or so when starting, I believe GM’s spec is 9.6V and the old DD starters were labeled as 9.5V starters.

A 10% drop which some are saying is excessive will pull a 13V battery bank down to 11.7V which is not that bad at all, and it’s 10% at max load, which you really should never really see.

[stormalong]

Originally Posted by a64pilot

An AC motor can do it, there is no shortage of AC motors in overhead cranes for instance, I suspect there are no or very few AC windlasses as AC adds another point of failure, either inverter or generator would be needed.

Just for the record those big overhead cranes are three phase motors and probably 440 volts. Does anyone make a three phase inverter?

I am a firm believer in the KISS system and stand alone systems. The more active components needed to complete a process the more likely it is to fail. Heavy wire is not an active component and it is maintenance free if properly installed. Batteries up in the bow are potentially loose cannons and need replacing periodically. With light wiring there is little power boost from a running engine. And before someone chimes in, a boost from an engine is beneficial but not required if you have a large battery bank. And who wants more weight forward - there is already ground tackle and a windlass up there.

[a64pilot]

Not all are, we had a single phase one in the repair station hanger.
Here is a single phase 120 VAC one ton hoist. 1350W, my VWC 2500 is a 1200 W so very much the same.
https://www.amazon.com/BEAMNOVA-2200...0862461&sr=8-2

[Dsanduril]

As noted way back at post #2, single phase AC induction motors just aren't well suited to windlass type loads. They don't self-start, they're pretty bad at torque, and they are generally pretty low on the efficiency scale.

A three-phase AC induction motor is a whole different beast. Self-starting, high torque, high efficiency.

Single-phase motors in appliances and things like that use speed to overcome their bad torque characteristics. That's just not windlass service - where you want highest torque at lowest speed. It's somewhat akin to diesel engines vs. gas. A three-phase motor can generate tremendous torque at zero RPM, and single-phase motor has zero torque at the same speed.

[BlackHeron]

Too bad some windlass makers didn't make 3-phase AC inverters that operated as frequency drive controllers/reversing switches and then use standard off the shelf 208/240v 3-phase motors on their windlasses?

It could be fairly easy to tie the inverter to the boat's ground and run an isolated delta with an ELCI cutout which would make the system very safe short of a phase-to-phase short. Power could run from the controller to the windlass with 10/3 or 8/3 cable without any issue.

Sure, inverters are expensive, especially custom 3-phase AC units, but variable frequency drives are already out there that probably wouldn't be all that hard to modify at a commercial scale.. It would save a whole lot of copper, with its expense and weight.

Dream a dream.

[rslifkin]

I think by the time you're looking big enough for people to stomach the cost of that, you're heading towards hydraulic windlass territory.

[mako]

Several comments being made about AC windlasses and 3-phase being impractical ideas, but that's in the small recreational boat world - which admittedly is pretty much what this forum is all about.

When I was living in Asia and SE Asia, I toured alot of shipyards building fishing boats generally in the 65-150 ft range. Generally they all had 3-phase generators and 3-phase motors (windlass, capstans, water pumps, etc.). It's easy enough to pull three different single phase legs off the circuit board to run domestic appliances and house circuits.

If you want to vary the speed of a motor (say a windlass) or reduce the locked rotor load, then add a VFD. About $300 gets you a unit and they're generally all industrial duty.

These were all run off generators, but they do make 3-phase inverters. It's basically 3 separate single phase units that sync together to provide the 3 phase. Nothing too expensive. However, you would have to carry some spare inverters in case one goes down.

I know all the above sounds complicated, and certainly is more than just a simple 12/24VDC boat, but it's really not too crazy. I rarely saw hydraulic systems because of the expense.

However for the OP, installing a VFD will convert your single phase power to 3-phase then it feeds the windlass motor and perhaps bow thruster too.

These systems aren't very popular in America, but you can check European sources or browse Alibaba to learn more about availability and vendors.

[Marrigoround]

Originally Posted by Mauruuru

Your solution is much simpler and much cheaper---buy a battery and locate it up in the bow. buy a suitable small charger and run AC from panel in stern up to the bow mounted charge. Keep the DC leads as short as possible to the winch.

I like this idea. The only negative that I can think of is the extra weight of the battery and the space that it takes up. I really like the idea of having the longer run at a higher voltage and lower current. The battery can be charged by the inverter, which will only be keeping it as float most of the time and running the bulk phase when the engine is running anyway. This method also allows for an isolated redundancy if god forbid, something were to go wrong with the main electrical system. Can anyone think of a good reason not to do this?

[a64pilot]

Originally Posted by Marrigoround

I like this idea. The only negative that I can think of is the extra weight of the battery and the space that it takes up. I really like the idea of having the longer run at a higher voltage and lower current. The battery can be charged by the inverter, which will only be keeping it as float most of the time and running the bulk phase when the engine is running anyway. This method also allows for an isolated redundancy if god forbid, something were to go wrong with the main electrical system. Can anyone think of a good reason not to do this?

As charge loads are rather low, say 10 amps or less at DC voltages, there is no need for an AC charger, you can charge with only 10Ga wire or so.
Another disadvantage of a smaller single battery is voltage drop under load, the larger the battery or battery bank the lower the drop, this is why big motors will have an 8D for starting and not a G31.
Then if you choose to put an AC charger up there with the single battery, will it be a good three stage one, or just a simple trickle charger? Good chargers aren’t cheap.
By the time, you build a good battery box with a way to secure the battery in bad weather and buy and install a charger, I bet you have spent more money than just big cable.

Plus with an inverter and a separate charger your failure rate is higher than a house bank, not less.
Plus if something were to go wrong with as you call it the main electrical system it’s likely you won’t want to upanchor before you get it fixed as without it there in no electronic navigation autopilot, engine starting, or radio com.

[LakeSuperior]

FWIW our Mason 44 was commissioned in 1999. If I recall correctly it
had a two 400 ah AGM house batteries under the V-berth that also serviced the bow thruster and windlass. The batteries were bolted down. The system worked flawlessly.

[mitiempo]

Originally Posted by Marrigoround

I like this idea. The only negative that I can think of is the extra weight of the battery and the space that it takes up. I really like the idea of having the longer run at a higher voltage and lower current. The battery can be charged by the inverter, which will only be keeping it as float most of the time and running the bulk phase when the engine is running anyway. This method also allows for an isolated redundancy if god forbid, something were to go wrong with the main electrical system. Can anyone think of a good reason not to do this?

More negatives are maintenance, periodic replacement, and cost. As a64pilot states there is more voltage drop from a single battery with short cables than a large house bank with long cables. If you install a good charger forward you are looking at several hundred dollars.

[Cadence]

Originally Posted by mitiempo

More negatives are maintenance, periodic replacement, and cost. As a64pilot states there is more voltage drop from a single battery with short cables than a large house bank with long cables. If you install a good charger forward you are looking at several hundred dollars.

I would have to contest that. The voltage drop is purely a function of the cable. As long as the same voltage is suppled and the battery is adequate to not being
"sucked down" the battery bank size becomes insignificant. Of course trying to get away with an under sized battery forward you, are correct..
A motorcycle battery won't cut it.

[rslifkin]

Originally Posted by Cadence

I would have to contest that. The voltage drop is purely a function of the cable. As long as the same voltage is suppled and the battery is adequate to not being
"sucked down" the battery bank size becomes insignificant. Of course trying to get away with an under sized battery forward you, are correct..
A motorcycle battery won't cut it.

Windlasses draw a lot of power. Any 12v battery will dip significantly in voltage when you pull 80A out of it for a couple of minutes. A single group 31 will dip quite a bit, while a 400+ amp hour house bank will dip a lot less. Plus, if you're pulling from the house bank, you usually have an alternator or 2 helping you. If you have a separate windlass battery with limited charging to it, you don't get the full alternator output to help, which makes the battery pull-down issue even bigger.

Even if the shorter cable run means you have 3% drop in the cables rather than 10%, the smaller battery with less charging input will likely lose more than that difference in cabling gains you. Now, if you have room and weight capacity for a huge windlass bank and your house bank is at the far other end of the boat, then a separate bank starts to make some sense.

[altruistica]

What's wrong with trying to find an electrical solution like a 110 /220V AC transformer to 12 / 24V DC to power the windlass? If you've got a 3000W inverter you've a potential 130A @ 12V or 65A @24V to play with. As long as you ensure the transformer is in a dry position and fit it in a waterproof enclosure, I'd have thought this would be an ideal solution.

[altruistica]

I see, after Googling, a transformer can only step up or down the voltage. A bridge rectifier would then be needed. All this must be contained in the ROHR battery charger that I obtained for a very reasonable sum of £60 the other day...charges 12V and 24V:
https://www.amazon.co.uk/dp/B07C36D9...t_details&th=1