Turnigy Marine 120 amp ESC

[Old School]

I have a Hobbyking Libero with an SSS 3674 2200kv motor running on 4s with a Turnigy 120 amp ESC. I fitted a 42/66 (1.6 pitch) lifter prop to persuade the tail to rise but as yet have not tested it. A member suggests that this combination will be too much for my 120 amp ESC.

Now my question. If I remotor with either a Leopard or SSS 3674 with around 1300 - 1400 kv running 6s, will this bring my amps down as compared to running the configuration above on 4s, please? I do not wish to overtemp the Turnigy 120 amp ESC. It is rated to 6s. A 1400kv motor on 6s will give me similar RPM to a 2200kv on 4s.

Is a 42/66 lifter prop too much load (heat, amp draw) on a 3674 motor, please? At a nominal 1200 watts stated for the Leopard motor then that equates to approximately 55 amps on 6s. At the maximum 1900 watts (Leopard 3674) that is approximately 90 amps on 6s which to me is within the capability of the 120 amp ESC.

With the SSS 3674 that I have now (quoted 2200 watts maximum) on 4s equates to around 150 amps. The way I see it running on 4s is more detrimental to the ESC than switching to 6s with a corresponding replacement 3674 motor (around 1400 kv).

[jim82]

Wouldn't hurt to throw an extra 35v 1000uf zl on it but you will be fine with the setup right now. I would as always run a minute then check temps the first time or two and when switching to a different prop just to make sure.

[Fluid]

To answer the OP’s questions:

#1 - yes, running the 6S setup will pull significantly fewer amps. If you are not constrained by racing rules running 6S is a good idea. I have run several of my 4S boats on 8S1P instead of on 4S2P, using a motor with a Kv around 900-1000. With the same weight I get the same run time and speed with half the amp draw.

#2 - the 42/66 lifter prop is probably okay as long as the boat doesn’t drag its transom much. Remember that the “stated watts” for a motor is just a guide for a safe range, believe me it is possible to pull way more than 90 amps from that motor. Many racers pull in excess of 100 amps from the smaller 36-56 RTR motors.


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[jim82]

I've ran the same boat same setup you have with a 120 everything ran cool with an x442 prop. That is why I said what I said

[Old School]

Many thanks gentlemen. While awaiting the motor to arrive I switched over the 42/66 lifter prop to a Grimracer 42/55 prop as maybe the former 1.6 pitch prop may have been a little aggressive for the ESC.

[Fluid]

You can always prop later. Hard to do that after the ESC burns down. The original prop may be just fine, but better safe than sorry.


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[Old School]

Many thanks. A prop is a lot less expensive than an ESC.