battery size

[Jerry YoungParticipant @jerryyoung62912]

whats the formula for working out the size of battery needed to run a single motor?

ie V & Amh

motor size is about a 540 or 600 which will run on 6-12v ,max amp draw at the moment is unknown

i don’t want to buy too small a battery or over do it with a wapping great power station either

[TelstarParticipant @telstar]

Hi Jerry

Battery size is dependant on more than the motor.   the size and type of model can often dictate the size/weight of battery that can be fitted.  I am of the schoole of thought that would rather fit a bigger battery than use lots of lead ballast to get the boat to its waterline.  As a retired electrical eng. I prefer to use higher voltages ie I prefer 12v system to 6v, but having said that I do use 2 x 6v batteries to provide 12v very often.

Perhaps you could let us know the type and size of model, so we can advise you better

cheers Tom

[Jerry YoungParticipant @jerryyoung62912]

hi tom

u.s. customs picket boat, 39 " long X 8" beam. 1/6 plywood hull with 1/8 plywood frame and keel. superstructure is 1/6 ply. plans call for a 1" prop.

according to the plans she does not sit very low in the water.

hope this helps

jerry

[TelstarParticipant @telstar]

Hi Jerry

I think this comes into the type ‘Fast patrol boat’.   To get a good performance I think you need to be looking at Nicad (or similar) batteries. Gel cells are about twice as heavy as nicads.   A 30mm prop (not a racing or ‘X’ prop) with a 7.2v  battery on somthing like Electronize 545-46 motor would draw something like 10A and get hot so cooling would be necessery. However a 543-23 motor would draw about 4A, but the difference in performance would be noticable.  Using say a 4200mAh batttery with the former would give roughly 20 min sailing, while with the latter you would get nearer 1 Hr sailing.

Hope this helps Tom

[Jerry YoungParticipant @jerryyoung62912]

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