bow thruster question

[coddock]

I have a thruster and windlass in my D/E boat that is powered by it's own battery. I don't use either one much, and always remove the battery and charge it up. This fall the battery was extremely low. After some investigation I realized this battery is not hooked in with the charging system.

So my question....can I simply run a cable from thruster/windlass power strip to battery switch or am I over simplifying this? Also,if so, what gauge cable?

 

[Sailorgp]

If the amp draw of your thruster is under 200 amps or thereabouts, yes, you can run the thruster directly from your battery switch. But it's a good idea to install a separate and easily accessed disconnect switch between the main battery selector switch and the thruster power strip. The gauge of the cable would be dependent on the length of the wire round trip to the thruster and the amp draw of the thruster itself. I would say a minimum of 4 gauge on very short runs and a small thruster. In my case, I have a small Side-Power thruster wired directly to my 3-way battery switch on my 26' Sisu and ran 2 gauge wire with a 200 amp fuse and the disconnect switch linked to below.

Side-Power Battery Disconnect Switch

 

[coddock]

There actually is a disconnect switch in line already. Thruster is a sidepower;I believe the smallest of the 3 they make. I will confirm amp draw and model #. The run to switch will be approx.12 ft.and I will also check that.

Can I "piggyback" connection onto existing connection on switch?

 

[Sailorgp]

As an additional note...I know a guy with a 32' Nordic tug where the Side Power thruster took off on it's own due to a malfunction in the motor control board...hence you want an easily accessed disconnect switch.

 

[Sailorgp]

By 'piggyback' do you mean putting two cables (#1 to starter motor and #2 to thruster) under the same stud?...the answer would be yes. But make sure all your connections are clean and tight.

 

[coddock]

As an additional note...I know a guy with a 32' Nordic tug where the Side Power thruster took off on it's own due to a malfunction in the motor control board...hence you want an easily accessed disconnect switch.

Funny...I had the same thing happen to me on it's maiden voyage (for me) while taking the boat home. It happened @ the entrance to the cc canal of all places.
Not being at all familiar with bow thrusters at the time,I was clueless and had no idea what was making all the noise. Needless to say we found the disconnect.

 

[Door#3]

As an additional note...I know a guy with a 32' Nordic tug where the Side Power thruster took off on it's own due to a malfunction in the motor control board...hence you want an easily accessed disconnect switch.

This happened to me once (1st year I had the boat) while cruising along on Stellwagen. Was quite a surprise, especially when I found that I had no way to shut it off. Ended up having to pull the fuse. Installed a shutoff as part of the fix.

 

[Door#3]

So my question....can I simply run a cable from thruster/windlass power strip to battery switch or am I over simplifying this? Also,if so, what gauge cable?

I would connect it to the charging system via some kind of combiner / isolator. If you hook it in directly a failure on that battery can drain your other battery(s) and put you in a bad situation. I am using a Yandina combiner. If you wire it correctly it will bring your forward battery into the charging system only when there is a net positive charge situation, so will not allow a bad battery on either side of it to discharge battery(s) on the other side.

http://www.yandina.com/c160Info.htm

As was mentioned the size of the wire will be determined by draw and total wire distance (both ways).

 

[Sailorgp]

My suggestions were based on the premise of eliminating the forward battery altogether
and simply powering the thruster directly from the main starting batteries.

 

[Door#3]

My suggestions were based on the premise of eliminating the forward battery altogether
and simply powering the thruster directly from the main starting batteries.

That will work, but since he already has a better setup, dedicated battery for the thruster & windlass... why not just charge that battery?

 

[Sailorgp]

That would be a real possibility and coddock can choose the route he wants to take modifying his installation.
For me, I have a relatively small boat (26ft) and try to follow the KISS (keep it simple stupid) when installing or modifying anything. My thruster works just fine off my starting batteries so why have a third battery in the bow when I really don't need one? On larger boats where the distance might be 40 or more feet round trip to the thruster from the starting batteries it would make more sense to have an extra battery installed locally near the thruster.

 

[coddock]

That will work, but since he already has a better setup, dedicated battery for the thruster & windlass... why not just charge that battery?

Thank you for clarification...I was confused. I agree and do want to use the setup as is but do need to get the battery into the charging system!

 

[Door#3]

Thank you for clarification...I was confused. I agree and do want to use the setup as is but do need to get the battery into the charging system!

Using the Yandina combiner (100 or 160) will be the cheapest and easiest way to get you there. The installation calls for connecting the POS lead of a battery that is in the charging system (using 6 gauge wire) to the POS lead on your thruster battery with the combiner in the middle. You will also need to bring a small 18 gauge ground wire from common ground to the combiner. I use this setup to charge my #2 battery when the battery switch is on 1.


Here are the instrauctions. I think I purchased mine at Defender.
http://www.yandina.com/acrobats/C160Data.pdf