Questions about ESCs

[Bill Macomber]

I've read some postings on the forum that running an ESC at part throttle for an extended period of time is really hard on the ESC. My question is, what is considered an extended period of time? A few seconds? A minute? Somewhere in between? I plan on getting a Raidor 150 and using a 6s power source. Thanks for any help.

[Fluid]

It isn?t possible to answer your question. It all depends on the WOT amp draw of the system, a low draw RTR can handle a lot of part throttle while a full race setup can?t. This is because the ESC switches on and off to control speed and whenever it switches on it sees full amp draw - which means heat. So part throttle at near top speed is easer on the ESC than part throttle idling along.

IME the Raider is a good ESC, but saying ?6S? really tells us nothing. What motor and prop? What hull? Sport running, SAW or oval racing? It all matters. If you absolutely need a number, 20 seconds total would probably be okay with most moderate setups....but at what speed? It all depends and experience is the best guide.



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[Bill Macomber]

Sorry to be so vague, I'm so new to the whole fast electric world that, clearly, I don't even know how to ask a question properly. I'm sport running an old Dumas 36 inch SKDADDLE with a Leopard 1000kv motor swinging an Octura x445 prop. I'm looking for speeds around 30 mph. Thanks for the reply, I'll try to do better next time

[HTVboats]

The missing piece here is what size motor. Watts? We use 1400kv 4074 motors for a "Q" (6S limited class) with the Raider 150 and pull 100-140 amps with an M445 prop on tunnels and mono's in the 34-38" range. A 4082 (similar KV) would pull more prop and overload the ESC. In your application the flat bottom will drag more water but the 1000kv will pull less amps. Depending on the total weight you will make 30mph easily. As you go up in KV or Prop you require more amps. Amps X volts = watts A 4074 in general is 2-2 1/2 watts 2000-2500w.

[Bill Macomber]

The motor is a Leopard 4082 1000kv.

[Fluid]

You did fine Bill. I assume that the prop is fully submerged. That is a big boat for a 45mm prop but fully submerged it should work. That motor will not be stressed, it can easily handle much more prop....but the hull may not. The Dumas SKs were designed for speeds in the low 30s, so the OP’s prop choice is probably good. What battery will be used, capacity in mAh and C rating?


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[Bill Macomber]

I'm using two 11.1 volt, 5000 mah, 50c batteries running in parallel for longer run time.

[HTVboats]

Two 11.1v in series makes 22.2v /5000ma Two 11.1 in parallel makes 11.1v / 10000ma.
As to your original question part throttle time does create more heat. I would avoid over 30 seconds as there is no definite answer here. Get a temp gun and monitor your motor and esc after short runs then extend run time. Use two water pickups one for motor and esc as low speeds reduce water flow.
Be careful with props as a 4082 can draw more amps than your esc will safely handle. With the speeds your looking for it should not be an issue. A smaller 3 blade (440) may give you more blade surface to push without diameter load. Have fun.
Mic

[Bill Macomber]

Ok. Thanks everyone for all the help and advice. I really appreciate it. This is going to be great fun!