8s build help

[Crash]

hi guys.
I am thinking of a new set up for my hull, its just for fun. not racing it.

im new so looking for your help and suggestions.

the boat is a 36 inch by 11 inch mono fiber glass


motor would be a leopard 4082 or 4090 series... KV rating?

thinking of the 240 or 300 swordfish ESC?
two 4s 6000mah 65c ?

size bullets?

Thanks guys

Dan

[StevenBryant]

I would run

Kv = 1200 ish
Motor = NUE 1527
Esc = 300 amp
Connectors = Castle 8mm

[Crash]

I would run

Kv = 1200 ish
Motor = NUE 1527
Esc = 300 amp
Connectors = Castle 8mm

thanks. Is there a lower budget motor you like?

[Crash]

so I am considering going 6s to 8s
will the 8s set up be faster over all or the same being that I would be keeping rpm near the same and running same props? what is the advantage of more volts to the same boat hull?

[Crash]

so I am considering going 6s to 8s
will the 8s set up be faster over all or the same being that I would be keeping rpm near the same and running same props? what is the advantage of more volts to the same boat hull?

am I better off buying lighter hull aka carbon fiber 33 inch mono and keep my 6s set up for that hull to go faster..????

[StevenBryant]

so I am considering going 6s to 8s
will the 8s set up be faster over all or the same being that I would be keeping rpm near the same and running same props? what is the advantage of more volts to the same boat hull?

The higher the voltage the less the amp draw for a given motor. Watts = voltage *amps (ampsmps = watts/voltage)


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[StevenBryant]

thanks. Is there a lower budget motor you like?

Yes Leopard

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[StevenBryant]

am I better off buying lighter hull aka carbon fiber 33 inch mono and keep my 6s set up for that hull to go faster..????

Difficult to answer as I don't know your current hull setup

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[Crash]

The higher the voltage the less the amp draw for a given motor. Watts = voltage *amps (ampsmps = watts/voltage)


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so I could run same props with less amp draw or larger prop with same amp draw?

[CraigP]

You can run the same prop, at the same rpm (motor KV change) at lower amps with higher volts. Of course, a larger prop will pull more amps. The big mistake people make when increasing voltage is they don’t change the motor to a KV that will produce similar RPM as the original setup. Trying to turn a motor with a KV for 4s on 8s, is a formula for disaster.

[larryrose11]

The other advantage of higher voltage / less amperage is less heat generation.
Power dissipation (heat) = current^2*resistance.
I recently burnt up a motor / controller from too much heat. Luckly, the boat is fine. Smells funny still. it was a 3100 KV motor on 3S (It came that way) .
The new setup is 1680 KV on 6S.

[CraigP]

Larry is dead on! I’ve got 1700kv motors in my 6s boats.

[Crash]

Awesome info guys!

rite now my lipos (3s 6000mah 50c)don't want to keep up with the props I am trying and boat will not perform as it should with its stock prop size....(proboat Voracity / stock prop 645 / 50 mph) I am seeing 42 mph max on that prop. I switched out stock motor (1650 kv) for 4090 1730kv and switched out 120 amp ESC to a 220 amp esc

[Alfa Spirit]

You can run :

1500 kV 4082
180A esc (HobbyWing)
2 x3S batteries 5000mAh or 6000mAh

Budget motor : TFL SSS 4082

https://www.tfl-hobby.de/Motore--Halter--usw-/Brushless/TFL-40-mm/4082/

[Crash]

Larry is dead on! I’ve got 1700kv motors in my 6s boats.

what lipos do you use with this set up, I have a similar se t up now.
I have two sets of 3s 6000mah 50c that can not keep up and two have puffed up.
I have one set of 3s 5000mah 70c they do better but still see a drop in voltage to 19.0 v and amps up to 350 @ 100% throttle