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[tomo55]

Hi,
      Ive just about completed a deans marine ASRL ,I noticed that on the water it seems to lack top end speed.
The recommendation was for a kestral motor and a 7.2 volt buggy type pack ,I used a 7.2 v 3000mah pack.
Am I right in thinking if I up the pack to a 7 cell 8.4 v or more that would help with the top end speed?
The model looks nice on the plane but I think (no expert) it could do with a little more.The motor will handle from 4.8 to 12 v .
Or should I go for a smaller 12 v lead cell?
Help please
Chris

[DickyD]

Go for it.

I have two Kestrals that run on 9.6V 4300mAh race packs.

I have one in my PT Boat and one in my American PGM.

I have watercooled them both as they tended to get a bit warm run flat out all the time.

PGM


PT Boat

[FullLeatherJacket]

"A planing hull without a lead-acid battery is like a fish without a bicycle".
Avoid SLAs for fast boats. The clue is in the "lead" bit. NiMH packs are FAR more efficient ref power/weight. You can also increase the voltage in increments of 1.2v - you're not just stuck with multiples of 6. You'll note that Dicky has either NiCAD or NiMH packs in both of his models.
You might also experiment with different props.
Suit yourself.
FLJ

[DickyD]

Sorry forgot to say, they are NiMH packs from Component Shop.

[tomo55]

Thanks Richard ,i will get one from component shop.
Chris

[malcolmfrary]

A point to bear in mind is that higher capacity cells tend to have more metal content and tend to be heavier.  The increase in weight of a 3000 over what the boat was originally designed for could be enough to reduce performance.  Having an extra cell to up the voltage will increase power, but that might get used up dragging the extra weight...
I would look for the same size motor with a top voltage equal to the battery voltage.  You might need a pilots licence for the boat then.  Avoid lead.