Connecting 12V Windlass to 24V bank

I have a 12 volt windlass and a 24 volt bow thruster with two 12 volt batteries in the bow wired to make 24 volts. The windlass is wired to battery bank in engine room and the cables are long and undersized.

Any suggestion for wiring the 12 volt windlass to the 24 volt bank so the cables will be shorter and hopefully less expensive? I was thinking of using a 24 to 12 volt converter but don't have any experience with them.

OTR, I moved your post into a new thread so your post can achieve greater visibility. Hoping someone with a similar setup can provide some guidance.

Also, I would refer you to Nigel Calder's book, Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems

just wire it to the poles of one battery....


here is another component that can come in handy if you change things around...


http://www.wmjmarine.com/bpspe.html

To expand a bit on psneeld's comment: wire your 12 V windlass to the positive and negative of one battery, preferably the one which supplies the negative to the 24V thruster. That way you won't get a short if you somehow tie the two negatives together.

I presume that you have some way of charging your 24V battery.

David

Center taping a pair of batts is theoretically not ideal.

But it works , well , as long as the low voltage battery does not get too depleted.

With the short use of most windlasses you should have no problem.

Each spring swop the batts place for place , as it might extend the service life.

For extra long run times a 1-2 rotary switch might allow selection.

What is the make of the windlass. I would change the motor for a 24 volt if possible. Or may be able to have it converted by a good starter/alternator shop.

Second that about finding a 24v motor. Drawing off 12v out of a 24v pair causes one batt to go low, the other to overcharge. How bad that happens depends on how many AH you ask of it, size of batts, how often its used, etc.

If NOT overloaded a 12V motor is quite happy running on 24V.

The hassle only comes IF you attempt to get the power a 24V motor could provide .

If you stick with the lifting rating the 12V is rated for it should be no problem.

Except that unless one changes the gearing it will spin the prop faster which will just lead to massive cavitation.

Center battery tap is definitely not advised, as others have said.

Motor swap to 24v or a voltage converter. Not sure if the converter is realistic due to the amperage involved.

Seems like the fishing crowd with 24V trolling motors have some ideas how to set the rig up with one exception. I saw a lot of discussion on the Continuous Wave forum that I believe is mostly abut Boston Whalers.

Most of the ideas add the second battery for 24V just temporarily....the rest of the time they charge individually as 12V.

psneeld said:

Seems like the fishing crowd with 24V trolling motors have some ideas how to set the rig up with one exception. I saw a lot of discussion on the Continuous Wave forum that I believe is mostly abut Boston Whalers.

Most of the ideas add the second battery for 24V just temporarily....the rest of the time they charge individually as 12V.

Click to expand...

As in using a battery switch?? Ingenious.

This is easy. Give your windlass a dedicated battery up front close to the winlass. Replace from battery to windlass with up sized cables to feed same. A short run, might be able to work something out for chain locker. Use the undersized cables for your charging circuit, charge the 12 volt battery with a small solar panel. You already have wiring from ER to new battery so 14 gage, even less from panel to ER is all additional wiring needed and it is likely dead wire from bridge may already be there on an older boat as surly ur Gulf Star is.

I did this to a my last boat to power a bow thruster and windlass to avoid a long run of very large battery cable. The fire risk concerned me also insofar I had a 100 amp charger. All that high amp traffic under decks concerned me. So I just did a work around for (perhaps unneeded) peace of mind.

You know it is never that simple.....

Here's one discussion with diagrams of possibilities....

Mixed 12-volt and 24-volt Primary Power with Three Batteries - Moderated Discussion Areas

Windlass is a Lewmar Profish 1000. I'll check the Lewmar site to see if a 24 volt motor is available and consider the cost. The 24 volt battery s charged by a 12 to 24 charger wired to the house bank. Running 24 volts to the 12 volt windlass would be the simplest solution and I wasn't looking to get more power than what I have now. Are there any concerns about burning up the motor?

Just checked, Lewmar doesn't make 24 volt motor for my model.

So you already have 12v leads from engine room to fwd to run the 12/24 converter? What gauge are those leads? If skinny maybe you can run heavier. Then windlass will run right off house batts.

Yes there are12 volt cables from the house bank now. However, they are as old as the boat and small. The reason I was looking at the thruster bank was to shorten the cable run by about 20 feet.

Windlass draws no where near what a thruster does, also volt drop is not that critical on windlass. So you don't have to be that anal about using thick cables.

Any idea what gauge the 12v cables are?

Most of it is 4 AWG that is old non-tinned somewhat corroded, maybe welding cable? There is a splice of newer 6 AWG where it connects to the windlass switch at the helm on it's way foreward. Maybe you are right about over thinking it after all it still works fine.

4ga should be plenty thick, but that is without knowing actual amp draw. Maybe just clean up cable ends or maybe put on new lugs.