Battery for Bow Thruster

[sailor0516]

What would be the best type of 12v battery for a bow thruster, deep cycle or starting?
How about the anchor windlass?
sailor0516

[rw58ph]

Deep as they have more total amp hours but still a high amp out put. The size of the battery bank is the question? Do you know the amps the thruster is rated?

[Matt sachs]

All I know about this topic is what I've read about it. It would seem a cranking battery is well suited for a high amp short duration draws, much like a thruster requires. Deep cycle batteries are better suited for sustained lower amp draws.

[smac999]

battery size plays a role too. IE you can't run a 500a thruster off a small starting battery. where as a large deep cycle will still take highish currents

I would say starting for thruster, and deep for windlass. as the windlass runs for a while when raising.

however both should only be used with the engines running and with a charging source reaching the forward battery anyways.

[ranger58sb]

One company that installs thrusters routinely also installs a bank of 2x Odyssey PC-2150 (Marine Group 31 equivalent) dual-purpose AGM batteries. (Sears also sells these batteries under their Marine Platinum Plus label.) You can look up the life cycle and cranking specs on the Odyssey websites...

-Chris

[smac999]

the other thing to keep in mind is where they are going. lots are under a vberth bed. so agm would be much better then gassing into a bedroom.. (and gives you the best worlds of starting + deep cycle)

[ranger58sb]

Originally Posted by smac999

the other thing to keep in mind is where they are going. lots are under a vberth bed. so agm would be much better then gassing into a bedroom.. (and gives you the best worlds of starting + deep cycle)

AGMs are vented, though, so there's still a little off-gassing... but yep, I think that's another reason why they're used in this application.

-Chris

[chrisjs]

Our bow thruster runs off 2 x 4D wet batteries through various devices to provide 24V.
They have their own charger fed by the generator/shore power. Our stern thruster runs off the one of the house banks ( 2x 8D's). You need to ensure that you have enough capacity as the draw is hundreds of amps.

[sailor0516]

Thanks again for all the information, these forums are great help for us who do not have long term experience and cannot afford trial & error.
sailor0516

[Roy M]

Keep things simple. Have two substantial battery banks, both of the same battery type (AGM, Gel or flooded). They can be differently sized. The big one is the house bank, the smaller is for the engine start, windlass and thruster. Always start the engine first, then use the windlass and/or thruster while you are actually making electrons. Have a parallel switch between the banks as a backup. Use combiners to keep everybody happily charged. Have the best alternator possible, and install photovoltaics.

[smac999]

Originally Posted by Roy M

Keep things simple. Have two substantial battery banks, both of the same battery type (AGM, Gel or flooded). They can be differently sized. The big one is the house bank, the smaller is for the engine start, windlass and thruster. Always start the engine first, then use the windlass and/or thruster while you are actually making electrons. Have a parallel switch between the banks as a backup. Use combiners to keep everybody happily charged. Have the best alternator possible, and install photovoltaics.

great on 30 foot boats. get on bigger boats the cable run is just too long to properly run bow thrusters. unless you're running wire bigger then your head.

I was on a 45' boat a few months ago. batteries at mid ship in engine room. battery switches in rear laz. probably a 100'+ bow thruster return run on a 45' boat. thing barly worked even with 4/0. put 8D in bow. used existing 4/0 for charging. thing actually works now.

[sailinglegend]

Originally Posted by Roy M

Keep things simple. Have two substantial battery banks, both of the same battery type (AGM, Gel or flooded). They can be differently sized. The big one is the house bank, the smaller is for the engine start, windlass and thruster.....

A better option, IMHO, is one substantial house bank and a very small starter battery for only starting the engine.

Run all the charging to the house bank, which includes the windlass and bowthruster batteries. This can be engineered to get a balanced charge/discharge.

If you use a bowthruster a lot then consider a separate bank just for this, with additional charging complexity and costs.

Our house bank is 1050 Ah and our starter is 27 Ah for a 56 HP Yanmar. It's a Red Flash AGM and has been lying on its side untouched for 9 years. Charged only by a 5 watt solar panel. KISS!

[deckofficer]

Originally Posted by ranger42c

One company that installs thrusters routinely also installs a bank of 2x Odyssey PC-2150 (Marine Group 31 equivalent) dual-purpose AGM batteries. (Sears also sells these batteries under their Marine Platinum Plus label.) You can look up the life cycle and cranking specs on the Odyssey websites...

-Chris

This is the way to go. Odyssey AGM is both a cranking and deep cycle battery. I've used these batteries in many different applications. The only draw back is the price, but I'm sure you and your boat are worth the extra cost.

[ranger58sb]

Originally Posted by deckofficer

This is the way to go. Odyssey AGM is both a cranking and deep cycle battery. I've used these batteries in many different applications. The only draw back is the price, but I'm sure you and your boat are worth the extra cost.

FWIW, local pickup at a Sears store (Platinum Plus branding; part number PM-1, I think, if they still carry them) can at least save delivery costs, and sometimes they have 'em on sale at even better prices.

-Chris

[undercutter]

Originally Posted by smac999

great on 30 foot boats. get on bigger boats the cable run is just too long to properly run bow thrusters. unless you're running wire bigger then your head.

I was on a 45' boat a few months ago. batteries at mid ship in engine room. battery switches in rear laz. probably a 100'+ bow thruster return run on a 45' boat. thing barly worked even with 4/0. put 8D in bow. used existing 4/0 for charging. thing actually works now.

Long cable runs are not recommended!! We use to blow the 350amp fuse until we installed a separate 8d in the bow as close as possible to the thruster. Left the existing cable runs in for charging. Make sure all switches are of good quality and can take the loads required.

Our Vetus thruster has a continuous operation of only 2 minutes and no more than 2 minutes per hour due to heat buildup as per manufacturers recommendations so I think a cranking battery is best to produce high amps for a short period.