Do you run the boat with nitro now? Let me try to explain the problem in terms a nitro user is used to.
What size prop is on the boat, and what RPM can your Nitro engine spin it?
A motor's KV is the RPM it wants to spin per volt, with 4800KV and 4s (16.8v) it is going to try to spin at 80,640 RPM.
Amps times volts is watts, and there are 746 watts to the horsepower, so pushing a 70A ESC to its limits on 4s, it can produce 1.5 BHP. 1.5bhp is not enough to spin a decent size prop at 80,000+ RPM. Half that prop speed or under will allow you to spin a prop that will actually push the boat.
Unlike a nitro that will fairly happily bog down and get nowhere near its RPM potential if over propped, an electric will get fairly close to its RPM potential when over propped, producing more power than is sustainable in doing so and will overheat. eg if it takes 15 bhp to swing a 45mm prop at 80,000, an electric will put 15bhp into swinging it, and might make it to 60,000, but that 70A ESC wont last long with 700A flowing through it and will burn up real quick.
Paul Upton-Taylor, Greased Weasel Racing.
Bookmarks