Re: Bow thruster does not work in one direvtion

Alan Leslie

This thread has gone off topic .....but ......
There seems to be a bit of confusion between short high current demand and deep cycle capacity.
480A for 10 seconds has little relationship to 300Ah deep cycle capacity.
Bowthruster consuming 480A for 10 seconds is only 1.33 Ah, 2 seconds only 0.267 Ah, so battery capacity is not the issue.
Providing your cabling is big enough to handle the instantaneous current, and the CCA capacity of your battery bank is high enough (ours is around 3000 CCA) it should be no issue for Lead Acid batteries - think truck starter motors etc
However, I believe that high current draw can be an issue for LiFePO4 batteries under certain conditions.
We have a 7.5kVA Onan and run both the 100A charger and the 30A charger when using the bowthruster, as well as the 175A alternator on the main engine, just to try to reduce the demands on the battery bank.

Our 12 balanced AGM batteries are now 6 years old and show no signs of deterioration as yet.
We are not big electrical energy consumers - the frig and  freezers are our main continuous consumers, we use gas for cooking.
We generally don't daily discharge below 85% capacity and with our 600W solar array, wind generator, and short use of the Onan we get our battery bank to 100% every day.
On the dock, the Victron Skylla 100A charger is always on.

Elyse SM437

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