12V Windlass off a 24V Bank

[IStream]

My boat has a dedicated 24V battery bank and charger in the bow to power a large thruster, along with a large 12V house bank aft of the keel. The original 12V Maxwell 1500 windlass is wired with 1/0 cable that runs all the way back to the house bank. I'd like to run it off the 24V bank up front to reduce voltage drop and wiring complexity and see two ways to do it:

1. Change the windlass' reversing solenoid and motor to 24V units. The problem here is that Maxwell/Vetus has discontinued the 24V motor. I don't know if the existing 12V motor could be re-wound or otherwise converted to 24V operation.

2. Wire the windlass to just the lower 12V battery of the 24V bank and wire in a battery equalizer (e.g. a Vanner 65-100) so the SOC of the batteries gets re-balanced every time the bank is charged. This is a common strategy on large motorcoaches, which have both 24V and 12V accessories run from a single 24V bank.

Any opinions/suggestions/advice/abuse would be welcome.

Thanks.

 

[Alex Dare]

About the only motors that are not available from Maxwell are those for the old Maxwell/Nilsson series and as far as I know they didn't have a 1500 model in that series. They should be able to give you the correct part# for the 24v motor.

 

[IStream]

About the only motors that are not available from Maxwell are those for the old Maxwell/Nilsson series and as far as I know they didn't have a 1500 model in that series. They should be able to give you the correct part# for the 24v motor.

Thanks, Alex. I called the local Maxwell dealer and they said that the part number for the 24V motor had changed and gave me the proper number. Cost for the motor is ~$500 and the solenoid's another ~$100. Given this, I decided to go the equalizer route. I found some new Cooper/Bussman/SurePower 100A units for a great price and will let people know how it goes if there's interest.

 

[Maine Sail]

Just be sure your "equalizer" can handle the in-rush loads associated with a windlass. These products are not inexpensive and a 24V motor would be the best solution. I have seen a number of equalizers toasted by high current motor starting loads. These are generally designed for loads that are not pushing their limits or exceeding it in in-rush.. It is critical to keep any series battery balanced thus many RV'ers use equalizers. For a windlass, or 12V winches on a 24V boat, I have seen them cooked so just be sure your equalizer is rated for the loads and in-rush. This could mean an equalizer that is double the size you think you need.

You may find an auto electric shop that can source you a 24V windlass motor for a lot less money..

 

[IStream]

Just be sure your "equalizer" can handle the in-rush loads associated with a windlass. These products are not inexpensive and a 24V motor would be the best solution. I have seen a number of equalizers toasted by high current motor starting loads. These are generally designed for loads that are not pushing their limits or exceeding it in in-rush.. It is critical to keep any series battery balanced thus many RV'ers use equalizers. For a windlass, or 12V winches on a 24V boat, I have seen them cooked so just be sure your equalizer is rated for the loads and in-rush. This could mean an equalizer that is double the size you think you need.

You may find an auto electric shop that can source you a 24V windlass motor for a lot less money..

Thanks, Maine. I managed to find two brand-new 100A Cooper-Bussmann equalizers at a great price, less than half what it'd cost to source a 24V motor and solenoid.

Seems there's two common ways to wire an equalizer. One way is to use it strictly as a 12V power supply by connecting it to 24V and ground on the battery and powering all the 12V loads through the 12V equalizer tap. Doing this, the max current is dictated by the equalizer's rating (100A in this case) and there's no way to deal with in-rush, so you can damage the load, the equalizer, or both.

The alternative is to connect all three equalizer terminals (24/12/Gnd) to their respective points on the batteries and run the 12V loads via the 12V battery terminal. This way, the load can transiently draw more than the equalizer's rated current by depleting the lower battery, which is then equalized with the upper as soon as a charging source is connected. As long as the equalizer is current limited and protected (which it is) and the draw on the lower battery isn't extended, you can get away with this to deal with inrush.

It seems the best way to do it is to wire as in the second case but parallel two equalizers so the combined current capacity exceeds or at least approaches the expected inrush currents. That's what I plan to do. My windlass is rated at ~140A operating current so the two 100A equalizers should easily handle steady-state operation, with the lower 12V battery supplying any portion of the inrush that exceeds 200A.

I'll let you know how it works out.

 

[Maine Sail]

Thanks, Maine. I managed to find two brand-new 100A Cooper-Bussmann equalizers at a great price, less than half what it'd cost to source a 24V motor and solenoid.

Seems there's two common ways to wire an equalizer. One way is to use it strictly as a 12V power supply by connecting it to 24V and ground on the battery and powering all the 12V loads through the 12V equalizer tap. Doing this, the max current is dictated by the equalizer's rating (100A in this case) and there's no way to deal with in-rush, so you can damage the load, the equalizer, or both.

The alternative is to connect all three equalizer terminals (24/12/Gnd) to their respective points on the batteries and run the 12V loads via the 12V battery terminal. This way, the load can transiently draw more than the equalizer's rated current by depleting the lower battery, which is then equalized with the upper as soon as a charging source is connected. As long as the equalizer is current limited and protected (which it is) and the draw on the lower battery isn't extended, you can get away with this to deal with inrush.

It seems the best way to do it is to wire as in the second case but parallel two equalizers so the combined current capacity exceeds or at least approaches the expected inrush currents. That's what I plan to do. My windlass is rated at ~140A operating current so the two 100A equalizers should easily handle steady-state operation, with the lower 12V battery supplying any portion of the inrush that exceeds 200A.

I'll let you know how it works out.

Please do. Today I get to deal with a 376A Vetus bow thruster that was powered with a single group 24 flooded battery & charged through a diode isolator after a 120A combiner and 24' of 4GA wire. The wire has signs of melting in numerous places, go figure........... Some people should not be allowed to touch wires......

Owner: "My bow thruster really sucks."
Me: "Well, yes it would, when wired that way."

On top of the massive voltage sag a single Group 24 battery will have driving a 370A+ load this owner also had another 2.3V or 20% voltage drop in the wire, and I am not even including the piss poor lug crimps done with a hammer or what his motor voltage was during the 700A+ in-rush..

Lets' assume the battery sags to 9V under a 376A load, then we subtract another 2.3V for voltage drop. This puts his thruster motor at just 6.7V!!!!!!!!!!!!!!!!

Yep, your thruster performance does SUCK......

 

[IStream]

Please do. Today I get to deal with a 376A Vetus bow thruster that was powered with a single group 24 flooded battery & charged through a diode isolator after a 120A combiner and 24' of 4GA wire. The wire has signs of melting in numerous places, go figure........... Some people should not be allowed to touch wires......

Owner: "My bow thruster really sucks."
Me: "Well, yes it would, when wired that way."

On top of the massive voltage sag a single Group 24 battery will have driving a 370A+ load this owner also had another 2.3V or 20% voltage drop in the wire, and I am not even including the piss poor lug crimps done with a hammer or what his motor voltage was during the 700A+ in-rush..

Lets' assume the battery sags to 9V under a 376A load, then we subtract another 2.3V for voltage drop. This puts his thruster motor at just 6.7V!!!!!!!!!!!!!!!!

Yep, your thruster performance does SUCK......

Craptastic! Please don't say it was a factory install...

 

[Maine Sail]

Craptastic! Please don't say it was a factory install...

No, a boatyard in Florida apparently installed the thruster.......

 

[IStream]

No, a boatyard in Florida apparently installed the thruster.......

I hope their fiberglass guy was better than their electrical guy.