Bow thruster wiring.

[derekh]

I am installing a vetus 7512 bow thruster and would like to ask opinions as the most successful wiring options. My first option is to use existing 35mm windlass cable to charge a dedicated battery obviously via a suitable split charge device. I would have minimal new wiring as the battery could be installed close to the thruster. My other option is to run 95mm wiring from the main batteries which would be about 12 meters. Which is the best option or is there another ?
Many thanks
Derek

 

[prv]

For windlasses, I'm always an advocate of just running the right sized wires - a one-off fit-and-forget job rather than the complexities of an additional battery. That said, I've just googled that thruster and learned that it takes 500 amps! Combine that with the fact that your batteries are apparently right aft, and I can start to see the appeal of a local battery. So I don't know what to advise.

For what it's worth, assuming you've done your calculations and 95mm^2 is the appropriate size, the overall diameter of such cable is 18mm - about garden hose size? The price (from the people I've used for two boat rewires now) would be £13.56+vat per metre, and their stuff is remarkably flexible for the size (I've never handled the 95mm, but their 35 and 50 bends through some very tight loops if required).

You're going to need a fair-sized bow-battery to supply 500 amps for long enough to be useful in a tricky berthing manoeuvre.

Pete

 

[Ripster]

I had this issue on a MOBO once when installing a BT and went for the specific dedicated battery to get the shortest cable run and smaller cables. When I worked out the hassle of routing the type and size of cable needed at the distance and the risks of them getting hot etc right through the boat, the batt seemed the best option and worked very well. The windlass however on all my various boats over the years has always run off the domestic bank.

 

[Sarnia]

There is another option, albeit a little more complicated.
Using a 24v thruster would give you 250 amps against 500 for 12v.
How to provide 24v can be achieved by adding an extra battery in your domestic bank, connected in a series parralel way to only provide 24v to the thruster which when selected receives the 24v and through cables now reduced in size, possibly by those existing for your winch parrelled with new ones or indeed upgraded to the 250amp.

Just a thought..

 

[philip_stevens]

I am installing a vetus 7512 bow thruster and would like to ask opinions as the most successful wiring options. My first option is to use existing 35mm windlass cable to charge a dedicated battery obviously via a suitable split charge device. I would have minimal new wiring as the battery could be installed close to the thruster. My other option is to run 95mm wiring from the main batteries which would be about 12 meters. Which is the best option or is there another ?
Many thanks
Derek

I have recently fitted a Vetus [FONT=Verdana, Arial, sans-serif]BOW5512C to our Konsort Duo, and my installation was to utilise the existing 40mm feed to the anchor windlass, and also fit a "starter" battery adjacent to the bow thruster. This would allow full voltage from the localised battery, with feed from the main general batteries, as a diversity feed. This way, I was able to get away with an 80Ah battery instead of the much heavier 108Ah battery. Your [/FONT][FONT=Verdana, Arial, sans-serif]BOW7512C would require a 120Ah battery. With my configuration, you could probably get away with the 80Ah battery I fitted,[/FONT]

[FONT=Verdana, Arial, sans-serif]I have fitted a 250A circuit breaker at the main batteries end, re-positioned the anchor windlass circuit breaker/isolator in the fore-cabin next to two isolators, (a) one to isolate the bow thruster battery from the main batteries, and (b) the other to isolate the bow thruster from all supplies. There is also a 250A fuse for the bow thruster.[/FONT]

[FONT=Verdana, Arial, sans-serif]With this configuration, I can run the anchor windlass direct from the general batteries, or allow it to be run from general batteries [/FONT]and[FONT=Verdana, Arial, sans-serif] the bow thruster battery, or just the bow thruster battery. I can also run the bow thruster from just the bow thruster battery.

Sounds complicated, but is not. It allows all motors and battery to be [/FONT][FONT=Verdana, Arial, sans-serif]isolated and protected.

For more information, and manual/installation downloads in English, go to the USA website http://www.vetus.com/manoeuvring-sy...usters/vetus-bow-thruster-75-kgf-12-volt.html[/FONT]

 

[William_H]

If it were me I would not use a local battery but rather use heavy wires. The thing being you use the same wires for the anchor winch as the Bow Thruster. Assuming the contorl relays of both are mounted in the bow near the respective motors. If you use a local battery I would suggest pretty heavy charging wiring as you would I imagine have the full output of the alternator try to charge/keep charged while using the iwnch or BT. Especially for prolonged use. good luck olewill

 

[Elessar]

I am installing a vetus 7512 bow thruster and would like to ask opinions as the most successful wiring options. My first option is to use existing 35mm windlass cable to charge a dedicated battery obviously via a suitable split charge device. I would have minimal new wiring as the battery could be installed close to the thruster. My other option is to run 95mm wiring from the main batteries which would be about 12 meters. Which is the best option or is there another ?
Many thanks
Derek

all good advice here bar the 24v idea for which you will need an additional 24v alternator. Note prv is right you will need 2 cables not one. I've fitted quite a few bowthrusters, used both methods. On my boat now i have gone for a dedicated thruster battery charged by the windlass cables via a voltage sensitive relay, so it is all fit and forget - well forget until the battery dies anyway.

When choosing the battery go for high CCA rather than being too hung up on AH. Bowthrusters are only used for very short periods of time so don't discharge a reasonable sized battery unless you are mis using the thing.

 

[davidwf]

I am installing a vetus 7512 bow thruster and would like to ask opinions as the most successful wiring options. My first option is to use existing 35mm windlass cable to charge a dedicated battery obviously via a suitable split charge device. I would have minimal new wiring as the battery could be installed close to the thruster. My other option is to run 95mm wiring from the main batteries which would be about 12 meters. Which is the best option or is there another ?
Many thanks
Derek

I would go with local battery charged via the windlass cables, only addition I would make is to fit a Sterling Battery to Battery charger at the bow thruster end. See http://www.shop.sterling-power.com/acatalog/B2B.pdf with 35mm you would be able to use a 50A version.

 

[VicS]

all good advice here bar the 24v idea for which you will need an additional 24v alternator. Note prv is right you will need 2 cables not one. I've fitted quite a few bowthrusters, used both methods. On my boat now i have gone for a dedicated thruster battery charged by the windlass cables via a voltage sensitive relay, so it is all fit and forget - well forget until the battery dies anyway.

When choosing the battery go for high CCA rather than being too hung up on AH. Bowthrusters are only used for very short periods of time so don't discharge a reasonable sized battery unless you are mis using the thing.

A 24volt battery could perhaps be charged using a 12 to 24volt charger eg Sterling's 122450 in the way davidwf suggests

 

[Elessar]

A 24volt battery could perhaps be charged using a 12 to 24volt charger eg Sterling's 122450 in the way davidwf suggests

Yes. True. Still pointless expense and complexity. The other ideas are better.....

 

[Sarnia]

all good advice here bar the 24v idea for which you will need an additional 24v alternator. Note prv is right you will need 2 cables not one. I've fitted quite a few bowthrusters, used both methods. On my boat now i have gone for a dedicated thruster battery charged by the windlass cables via a voltage sensitive relay, so it is all fit and forget - well forget until the battery dies anyway.

When choosing the battery go for high CCA rather than being too hung up on AH. Bowthrusters are only used for very short periods of time so don't discharge a reasonable sized battery unless you are mis using the thing.

Whilst I agree it is a more complex way of doing things, a change of alternator not a must as the batteries can continue to be charged when in 12v config.

When using the truster, charging could be switched off when the 24v config is selected to use the thruster.

The 24v confit would only be available to the thruster.

On reflection it is not the best way forward, just an alternative thought, a complicated method, but workable, but the best idea in my opinion is to run the cables you need as olewill has also advised, you kno exactly where you are, no extra battery in the forepeak, no extra charging challenges, a very KISS idea. Maybe an increase in the domestic bank is adviseable, but without the problems of an isolated battery forward. so for me, go for the heavy duty cables.

 

[nigelmercier]

My bow thruster is 24V, whereas the rest of the boat is 12V (until I added 24V Jabsco Electric Conversions).

If I was doing this myself, I would have put the batteries next to the thruster, as a bit of extra weight here is handy if you are turning into the wind. If our forward water tank is empty, I sometimes get someone to stand there.

 

[Sarnia]

Not entirely sure the bows a good place for batteries to be located, consider what is happening to the lead acid inside one when beating, or even on a reach in bouncy conditions, not what they were intended to cope with. In my opinion they should be safely stored in the most stable area available.

 

[pheran]

I can't help thinking there is merit in keeping the cables to high demand items as short as possible. My boat, as built, has a separate, sealed 135Ah battery shared by the winch and the thruster in its own sealed and ventilated compartment, and less than 3 feet from the respective motors.

Picking up on comments above, what did surprise me when I came to replace this battery was to find it was one of the 'mixed-use' deep cycle leisure type. With short, high current bursts as the requirement, bit like starting, I had expected a starter type battery but having checked with a number of battery suppliers and a couple of thruster manufacturers, I was assured that the deep-cycle route was the way to go. So you live and learn......