Help! ESC Bad? Motor Bad?

[rgc213]

Both bad?

I've got a Bushwacker that I've recently converted over to the flaps version, and been trying to re-learn how to fly with the flaps.
Things go well for a time, but after about 2-3 minutes of flying, the power seems to drop off, and within another minute or so, the power is to the point where it cant keep the plane in the air.

I didn't think anything of it the first couple times, chalked it up to pilot error, but this last time, after retrieving my plane, I started the motor on my way back to the launch point, and after the couple minutes, the motor did lose power and kind of fluttered. Even at full throttle, the plane didn't seem to want to leave my hand.

I'm using a C pack (older style Emax) motor and 30 amp ESC on a 2200 mA 3S. The motor has seen quite a few crashes, starting out as my first learning plane the tractor versawing.

Any insight would be welcome, though I'll probably just start switching out components till it works again

reub

 

[Merv]

Could it be the battery, not getting fully charged or is it getting old? In my experience, motors or ESC just fail, they don't lose power as you described.

 

[FDS]

You need to check the cell voltages and ideally internal resistance of that pack. You can use a cheap lipo check meter for that. It sounds like the pack is dead, what size and C rating was it?

 

[rgc213]

Interesting....i never thought that could be it.....
It is an older pack, GensAce 25C 2200mAh 3S, probably 2ish years old.
Still gets a balanced charge though.

One of the solders to the xt60 connection has come loose, and i have it just taped up, rather than a proper resolder.

Maybe ill try a different pack before switching out the other stuff.

 

[FDS]

Taping lipo connectors is BAD. If that’s an example of your approach to battery care then the lipo is definitely your problem.
Just balance charging doesn’t guarantee your cells will all be fine, you should always check the individual voltages and they should be +/- 0.1v of eachother. One cell can be bad from being ragged and the other two can be good, the pack voltage nosedives under load, resulting in the symptoms in your OP.
Please help yourself from having a crash or fire or both by not flying this pack again until the cell voltages have been properly checked and the connector PROPERLY REPAIRED AND INSULATED. Lipo short circuiting is not a joke and can result in injury to you, damage to your property or a fire on your flying field, all of which are not funny.

 

[quorneng]

"One of the solders to the xt60 connection has come loose, and i have it just taped up,"
Whilst the battery may be an issue I would be very concerned at a 'taped up' soldered connection. It will make a poor electrical connection compared to solder. It will tend to heat up at the high amps going through it at full throttle which will make the connection even worse.
It will fail completely very soon and the plane will then have no control at all and will crash.

 

[Wildthing]

I had a battery that would balance charge no problem but one cell would drop to almost 0 volts under load within a couple minutes if that , let the battery sit for 30 seconds and that cell would come right back up

 

[rgc213]

yeah, think I'll retire that pack, power it down and dispose of it properly.

On another note, I tried a different pack today, and things seemed better....
but when I put it into a spin, I lost power completely, than at the last second regained power.
I still crashed, but since I was able to pull up a little before impact, it didn't do any real damage and only broke a prop.

I threw on another prop, and did some more testing, and I think the problem is that the esc is overheating. It was almost too hot to the touch after my last flight. Currently, there is no airflow over the esc, and it's been hot here (80F+, flying in full sun). When I've been "losing power", I think its when the esc fails, then as it cools, it reconnects and I get the power back.

Right now, I have the esc in a power pod buried in the fuse. I'll try cutting some air flow holes and see where that gets me.

 

[FDS]

If your ESC is too hot to touch it’s not going to get fully better with airflow, you are putting too much load on it. What is the motor, esc and prop combo?
Remember air particles don’t scale down so the scoops will have to be big to make any difference.

 

[rgc213]

It's the FT C Powerpack- Emax GT2215/10 Motor, Emax BLHeli 30 Amp ESC, 10x45 Prop. Also tried it with a SF 9x47 prop, same issues.
One would think this combo would be OK, since they sell it together......

 

[FDS]

What KV is the motor? If you are running a 10” prop on 3s at higher rpms you will be getting it warm, even without summer heat.
If you have crashed the motor a lot a new one might not be a bad idea. Get a slightly larger 900-1000kv and run the 10 inch prop on that.
I don’t like the SF style props, maybe try a 9x3 APC or Master Airscrew and see how that does. What you are seeing is a high load being put on the ESC due to a large, pitchy prop being added to by the warm temps.