Trex 500e Motor Cutting out

[Bungy15]

Trex 550e combo with all standard electrics fitted, Let me try to explain what’s happening as I’m not to sure what to try next, I had a couple of supposedly good quality batteries (5000mah 25c 6s) that were used for about 6 flights each just hovering and lazy eights etc, after flying each cell was reading 3.84v ish. I always balance charge at 1c or below and now both batteries have now packed up on cell number three not accepting charge for some reason. I’ve sent these back and while I’m waiting I thought I would try some cheaper ones. Again I’ve opted for 5000mah 25c 6s but after 3 minuets of hovering and slow forward flight the motor cuts completely with no reduced power warning, the second time this happened caused me to tip on bounce landing and scat both sets of blades. I’m now wondering if the standard ESC is at fault or the cheaper batteries. I haven’t mentioned the makes of the batteries as I’m new to this posting and not to sure about naming products but I suppose if there is a problem everybody should know.

Any help in the direction I should take next would be greatly appreciated

[st200ol]

Firstly check your charger, what charger are you using? If you can try a different one, do.

It could be that the lipo's you are using are suffering from voltage sag under load, this will cause the ESC low voltage cutoff to be triggered, or it could be that the charger you are using is not charging/balancing the battery properly.

[Bungy15]

Thanks for quick reply, I've three Overlander RC-6S PRO chargers so i've sort of eliminated that as being a problem unless there is a common fault, all the cells are balancing out at 4.20v. The Turnigy battries are probably at fault as you say sagging under load causing the voltage drop. Probably should have gone for a higher C rating. Shouldn't there be a reduce power waring instead of the motor cutting completly? the ESC is set on high cut off voltage protection. The original Overlander battries flew perfectly for 6 mins but as i say the 3rd cell packed up on both of them

[Syclick]

Overlanders should be good batts. If all batts were reading the same-ish final voltage it rules out a charger fault.
Unless you have been incredibly unlucky and managed to get several duff lipos I'd suspect something like a far too tight motor pinion mesh putting too much load the motor - or possible an esc fault.
That could also explain the last batch of lipos failing after such a short time.

[Bungy15]

Everything is free running with no tight spots on the gears ect, I have converted to belt drive tail but thats all free running too, Im beginning to think I'll try another ESC but being relitively new to this larger model flying wasn't to sure what to do. are there any ESC that can be recomended and is it just a simple change over from the stock one?

I dont mind scatting blade when its my fault but..... or perhaps it is my fault for trying cheaper battries?

Thanks everybody

[dani_r]

Did I read that right?? You're running a 5000mah lipo on a Trex 500??

My bet would be on an ESC fault. As any other voltage issue with the lipo etc would give the low voltage warning from the ESC.

[scuba steve]

i have to ask....are you using 5000mAh 6S batteries on a Trek 500 ? i use them on my 550 but can only fit a 3000mAh 6S on the 500.

[Syclick]

So it does sound like it could an ESC issue. I use the HW Platinum 80 on my Tarot 500 and it's served me well - but I wouldn't say that it's as good as the stock Align one should be.
I would suggest sending it back - but knowing Align's customer service I wouldn't hold your breath.

[Bungy15]

Sorry.... Well spotted, Dumbo me it is a 550e Thanks i'll see if i can edit the title ?

[dani_r]

Sorry.... Well spotted, Dumbo me it is a 550e Thanks i'll see if i can edit the title ?

I think you have to get a moderator to change the title buddy either way, that's cleared up!

I'm pretty sure it's an ESC fault to be honest. Do you still have servo controls when it cuts out? Are you using an external Rx pack or anything?

[Bungy15]

I do still have servo control and if i close the throttle and start again the power is back, I think it might be a good idea to tie it down firmly and run it with a battery cell checker connected up to see what happens to cell voltages.

[coolice]

Hey.

The stock 550 ESC does work well, the inbuilt BEC is marginal on a model of this size so its advised to fit a seperate BEC power supply for the servos.
As you were doing ok and then problems developed I'd also suggest looking at all the solder joints between main battery and motor, as if there is a dry joint here then the ESC will have to work harder and runs the risk of failing or tripping out.

The battery C rating is not really a problem, unless you are doing power hungry manouvers.
I would set low cutoff though over high, as the high one will be more trigger happy. Then rely on your timer to tell you to land.

What throttle curves are you running?

When you flew the model for 6 minutes what mah went back into the packs?

Is this machine flybarless of flybarred?

Have you felt the ESC and motor after the cutout, is either one excessively hot?

Motor mounting screws, are they just the right length and not too long and shorting out the internals of the motor? A simple mistake that's hard to find.
.

[dani_r]

Hey.

The stock 550 ESC does work well, the inbuilt BEC is marginal on a model of this size so its advised to fit a seperate BEC power supply for the servos.
As you were doing ok and then problems developed I'd also suggest looking at all the solder joints between main battery and motor, as if there is a dry joint here then the ESC will have to work harder and runs the risk of failing or tripping out.

The battery C rating is not really a problem, unless you are doing power hungry manouvers.
I would set low cutoff though over high, as the high one will be more trigger happy. Then rely on your timer to tell you to land.

What throttle curves are you running?

When you flew the model for 6 minutes what mah went back into the packs?

Is this machine flybarless of flybarred?
.

Good shout on the dry joints. If in doubt just re-melt the solder on all the connectors just to be sure

[st200ol]

Good shout on the dry joints. If in doubt just re-melt the solder on all the connectors just to be sure

Its not good practice to do this, the problem may re-occur later. Best to remove the connector completely, remove excess solder from wire and connector and resolder.

[Bungy15]

Thank you all for all the useful information, I'll check out all the solder joints etc and report back. The throttle curves im running are Normal.. 0,58,80,90,100 Idle up 1and2.. 100,90,80,90,100. I will set the ESC to low voltage and use timer. I didnt think to check the temperature of the ESC or motor after cutting out but in the past they have only been warm after the 6min flights. I'm learning all the time and havent checked to see what mah went back into the packs in the past but with this problem showing up i will keep a log of all battery charging info and adjust flight timer to suit. The model is flybarred