Just fried an ESC and I don't know why.

[Henry]

I feel like I'm missing a fundamental piece of information, hoping someone can fill the gap.

I have been bench testing my electronics to see if I need more grunt to fly my over weight Tiny Trainer. I have had the following setup
6045 Prop
2204 Motor
20 Amp ESC
800 mAh 2S 20C

When I ran this up I was measuring 6 Amps at full throttle and I think 7.8 volts.

I then, for curiosity sake, switched the battery to a 2200mAh 3S 20C. I ran the motor up but before I could even get to half throttle the ESC was cooked. I didn't get to see how many amps it was drawing.Why if it was only drawing 6 amps with the 2 cell would the 3 cell fry the ESC?

 

[Bricks]

Does your esc and motor say it can be run on 3S. Sometimes electronics go up in smoke for no apparent reason bad component or soldering it has happened to me in the past POOF gone.

 

[Henry]

Both the ESC and motor are OK for 3S. The ESC is supposed to be good for 4S.

 

[Hai-Lee]

Was the ESC pre-used and possibly Pre-damaged?

Were the motor connections properly insulated from each other at all times?

Was the ESC still in its heatshrinked insulation?

Finally check the motor to see if the windings have been heated, (colour changed).

 

[Henry]

Was the ESC pre-used and possibly Pre-damaged?

It was new but I've flown it a couple of times.

Were the motor connections properly insulated from each other at all times?

Yes

Was the ESC still in its heatshrinked insulation?

Yes

Finally check the motor to see if the windings have been heated, (colour changed).

Doesn't look like it.

I'm guessing from your questions that using the bigger battery shouldn't have been a problem.

 

[Hai-Lee]

The battery voltage was fine and it was the ESC that determined the current draw so the battery size was and is irrelevant.

If everything was new then either the motor or ESC was faulty. If the motor is faulty then you could FRY another ESC to verify testing the charcoaled ESC is pointless.

As for your measuring methodology I hope that your measurement of 6 Amps at 7.4 volts was the Peak current and not the average. Some brands of ESC are rated at their maximum current capacity and there can be a considerable difference between Peak and Average currents especially on motors that are a little worn or suffering from minor crash damage.

 

[PsyBorg]

6 amps at full throttle seems a tad low to me swinging a 6045 prop but I have not used 2s for anything. I would suspect maybe the esc had issues already and the higher voltage pushed it over the edge.

 

[SlingShot]

..and one observation: that 2204 should be able to haul that Tiny Trainer effortlessly all over the sky. What kind of weight are we talking about here?

I managed to fry my very first ESC by wiring the battery plug on backwards

 

[Henry]

..and one observation: that 2204 should be able to haul that Tiny Trainer effortlessly all over the sky. What kind of weight are we talking about here?

In New Zealand our foam board is about 30% heavier than the US Readiboard. That's why I was running some bench tests to see how many watts I had available to haul the plane around.

 

[Hai-Lee]

I am in Aus and use the same weight FB as you have access to and I use 2205c 1400Kv on 3S with a 6 x 5 prop and the trainer flies great. With the high Kv 2204 it should do even better.