20HP Bow Thruster, 24VDC Battery Bank

Boats, Jet Skis, Kayaks etc., including hovercrafts
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fechter
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by fechter » Oct 12, 2017 2:15 pm

Any 3 phase motor is reversible by swapping any pair of wires (in theory). There is a wide selection of 440v motors out there, and the cables needed would be much, much smaller than what a 24v motor would need. Try searching eBay for "440v motor 3ph". Keep in mind that 20hp or anywhere close to that will be physically very large. You may get away with a smaller hp rating since you don't need to run it continuously.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 12, 2017 6:08 pm

fechter wrote:Any 3 phase motor is reversible by swapping any pair of wires (in theory). There is a wide selection of 440v motors out there, and the cables needed would be much, much smaller than what a 24v motor would need. Try searching eBay for "440v motor 3ph". Keep in mind that 20hp or anywhere close to that will be physically very large. You may get away with a smaller hp rating since you don't need to run it continuously.
Does that hold true for both delta & wye configurations?

Ok, maybe I should verify if the winch uses all 3 phases. Pretty sure it's a hand lever that shifts the rotation, no switch

If a genset has to be fired up for docking maneuvers, I'm sure that's not an issue

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by fechter » Oct 12, 2017 7:46 pm

Recursive wrote:[
Does that hold true for both delta & wye configurations?

Ok, maybe I should verify if the winch uses all 3 phases. Pretty sure it's a hand lever that shifts the rotation, no switch

If a genset has to be fired up for docking maneuvers, I'm sure that's not an issue
Yes, it would be true for both delta and wye. You can measure the voltage across every combination of wires when it's running to verify it's using all 3.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 14, 2017 12:55 pm

Ok, starting to see that maybe I'm looking for a solution that won't be easy

Saw this: http://abttrac.com/sites/default/files/ ... usters.pdf

ABT-TRAC has DC systems, but only up to 12HP. Their AC systems can perform as needed for my project, but the catch is that they require an AC diesel generator for the primary power supply

I'm guessing that if ABT-TRAC did not consider it worthwhile to try generating the AC supply with a inverter, possibly due to the power losses involved, then continuing to look for such a thing may just lead me to someone who doesn't know what they are doing?

The amp draw from a 24 volt battery bank to provide 10, 20 or even 40 horsepower can't be less than what a similarly-powerful AC system's inverter would be. Except that some losses in the proposed inverter will add amperage

I'm guessing a BLDC system won't be much different

I'm going to finalize this pursuit, by recommending either a very low-power 24 volt motor (less than 10HP), or make use of the genset for direct AC power

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by amberwolf » Oct 25, 2017 12:49 am

Probably not practical for this boat, but:

https://endless-sphere.com/forums/viewt ... 39&t=91216

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by liveforphysics » Oct 25, 2017 4:33 am

Recursive wrote:Ok, starting to see that maybe I'm looking for a solution that won't be easy

Saw this: http://abttrac.com/sites/default/files/ ... usters.pdf

ABT-TRAC has DC systems, but only up to 12HP. Their AC systems can perform as needed for my project, but the catch is that they require an AC diesel generator for the primary power supply

I'm guessing that if ABT-TRAC did not consider it worthwhile to try generating the AC supply with a inverter, possibly due to the power losses involved, then continuing to look for such a thing may just lead me to someone who doesn't know what they are doing?

The amp draw from a 24 volt battery bank to provide 10, 20 or even 40 horsepower can't be less than what a similarly-powerful AC system's inverter would be. Except that some losses in the proposed inverter will add amperage

I'm guessing a BLDC system won't be much different

I'm going to finalize this pursuit, by recommending either a very low-power 24 volt motor (less than 10HP), or make use of the genset for direct AC power
Have you considered buying a used EV to be a donar? Leafs running go for 5k with clean bodies and $2-3k with bodywork damage (which you don't care about).

If you find a 2013+ you can take its HVAC unit and 12vdc DCDC converter as well.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 25, 2017 1:43 pm

liveforphysics wrote:
Recursive wrote:Ok, starting to see that maybe I'm looking for a solution that won't be easy

Saw this: http://abttrac.com/sites/default/files/ ... usters.pdf

ABT-TRAC has DC systems, but only up to 12HP. Their AC systems can perform as needed for my project, but the catch is that they require an AC diesel generator for the primary power supply

I'm guessing that if ABT-TRAC did not consider it worthwhile to try generating the AC supply with a inverter, possibly due to the power losses involved, then continuing to look for such a thing may just lead me to someone who doesn't know what they are doing?

The amp draw from a 24 volt battery bank to provide 10, 20 or even 40 horsepower can't be less than what a similarly-powerful AC system's inverter would be. Except that some losses in the proposed inverter will add amperage

I'm guessing a BLDC system won't be much different

I'm going to finalize this pursuit, by recommending either a very low-power 24 volt motor (less than 10HP), or make use of the genset for direct AC power
Have you considered buying a used EV to be a donar? Leafs running go for 5k with clean bodies and $2-3k with bodywork damage (which you don't care about).

If you find a 2013+ you can take its HVAC unit and 12vdc DCDC converter as well.
That or a forklift. The very first thing I thought of after hearing this idea was to look into buying a second-hand forklift for the parts. Then I re-thought it and decided to see if there were some better alternative. Looks like my 1st hunch was the best one. Simply going by how much horsepower is involved, and what I would expect a forklift to need. I hadn't even got into battery bank voltages or cabling sizes, I just know that you can't make horsepower from thin air

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