Bow Thruster and/or Windlass Battery Type?

[S/V Illusion]

On another forum, there was a discussion with varying opinion about which type battery to use for these applications - start battery or deep cycle.

I am thinking the answer isn't clear in that a thruster and especially a windlass create more than a short-term draw, albeit a small one.

What type do people use to power these and what is the basis for your opinion? Or does it make much difference?

[motion30]

I don't what is proper but I use deep cycle for mine with no problem The thruster does use a good bit of power

[gbanker]

We have used a deep cycle batteries for both applications. The logic being that both the thruster and the windlass may be engaged for longer periods than one would normally run a starter.

[Jentine]

I run mine off the "house batteries" but there is an interlock that prevents the use of the windlass without the engine running due to the high current draw.

[Stevens 47]

Nigel Calder has written about this topic in his book Boatowners Mechanical and Electrical Manual on page 40-41. He does not address the battery type, but does go on to say that he thinks that the installation of a battery bank to operate the windlass/bow-thruster is flawed. The reason being that most of the time one operates those devises the engine is running. As soon as the windlass is turned on the engine driven alternator will go into high output, resulting in high charging currents, therefor the cables to the battery will need to be rated for the maximum output of the alternator. Thus the cables will be not much smaller than those needed to run from the house bank. He goes on to state that the battery up forward will see lower charge voltages thus a undercharged battery with the resultant sulfation or premature death. Worth a read.

[CharlieJ]

As usual, the manufacturers usually have an opinion and it is spelled out in their documentation. I know that Sidepower requires a specific CCA capacity for its units and does not mention the amp-hr capacity of the battery or battery bank.

[MarkJ]

The boats engine will *always* be on when a bow thruster or windlass is working.

Mark
PS I wanna boat big enough to have a bow thruster

[GeoPowers]

We use the starter battery for the windlass. Rationale- it was like that when I got the boat, ever had a problem. For the my bow thruster, my wife likes just about anything, but her favorite food is probably sushi. That said, my bow thruster can be a bit temperamental at times, but this is usually fixed by gentle taps and sweet talking it!

Seriously, if I was doing it all over again, I'd probably put the windlass on the house bank, since you have to have the engine key "on" for it to work on the starter bank for my boat. This produces a constant loud beep which is pretty annoying when trying to drop the hook or get underway under sail!!

[HorizonMarine]

Interesting that MarkJ (Beneteau 393) wants a boat big enough to have a bow thruster. Then next post from GeoPowers (Beneteau 393) talks about his bow thruster... MarkJ get a thruster, ....your boat qualifies

[MarkJ]

Originally Posted by HorizonMarine

Interesting that MarkJ (Beneteau 393) wants a boat big enough to have a bow thruster. Then next post from GeoPowers (Beneteau 393) talks about his bow thruster... MarkJ get a thruster, ....your boat qualifies

I thought he had good taste!

[GeoPowers]

Originally Posted by MarkJ

I thought he had good taste!

Opps, sorry I wasn't clear in my post...my wife is my bow thruster!

[S/V Illusion]

thanks for the comments - guess it really makes no difference or if it does, the difference is too trivial to be clear

[btrayfors]

Originally Posted by MarkJ

The boats engine will *always* be on when a bow thruster or windlass is working.

Mark
PS I wanna boat big enough to have a bow thruster

Yeah, maybe for the bow thruster, but not necessarily for the windlass. In the Caribbean I would very often sail up to the anchorage, and sail out the anchor in the morning. No motor. Sometimes do the same here on the Chesapeake.

And, what happens when your motor is dead? Do you just call TowBoat US or the Coast Guard?

IMHO, a sailboat should be able to operate its windlass with or without the engine running. So, I guess, I don't agree with Nigel on this one.

By the way, Mark, I sailed for a couple of years in Indonesia without an engine years ago. But then, I had no windlass either and was much younger :-))

Illusion: probably makes little difference if the engine is running. But, if you like to sail on or off anchor, or believe that some day you'll HAVE to, then the deep cycle battery solution works well. At least, it has for me for the past 12 years. BTW, my dedicated windlass battery bank consists of two T-105 golf-cart batteries installed in the V-berth. Very short cable runs to the windlass motor, and an Iota DLS-55/IQ4 to charge them from shore, generator, or inverter. Can get quite a few anchor drops and retrievals with no charging at all.

Bill

[MarkJ]

Originally Posted by btrayfors

I would very often sail up to the anchorage, And, what happens when your motor is dead? Do you just call TowBoat US
Bill

How about TowBoat World?

I used to be able to sail up to a mooring when I was a kid, but these days just do everything the double safety way.

The other thing is the auto pilot is going to be turned on shortly after the pick is up so I would prefer to have full batteries.

Remember, with the cruising we are doing every anchorage is new. Every anchorage is in some dicky part of the world where the depths were measured in WW2, channel markers don't exist and fish traps, canoes and logs abound. Its really a bit nervy motoring into and out of anchorages here. It would be grey hair makiing to be sailing in.



Mark