Problem with ESC or motor

[Steve McIntosh]

Hi ,

New to this and need some advice before I spend more money!!!

I recently bought myself a Bixler 2 from Hobby King and a Turnigy 25a ESC to go with it. First time I flew it(on a buddy box mind) the plane flew beautifully for the first 2-3minutes then when for a further 2mins when I tookover on the buddy box. Then the motor died and my buddy took over and landed it, seemingly under full control.

Everything seemed OK so we tried again but within 1min the motor again died but it was still under full control and landed safely. Neither the ESC or motor seemed particularly hot but I admit I am no expert.

I tried everything today and again after a couple of mins the motor dies and then seems to be trying but keeps cutting out and running in fits and starts.

Am I right in thinking it is a duff ESC or is it likely to be just overheating(in which case how do I cool itO or is it more likely to be the motor overheating(I assumed if that was the case it would simply burn out!!!)

Thanks in advance

Steve

[Andrew Russell 2]

You could try putting the esc out in the air flow to aid cooling

[Pete B]

Hi Steve,

Welcome to the forum! It could be one of several issues but the simplest would be to ask how the ESC is mounted within the fuselage? The ESC will have 'flat' side and a 'bumpy' side, in simple terms and they are often mounted using double-sided servo tape or Velcro.

The neat and tidy way would be to use the flat side for the tape but that is the heatsink and if it's mounted against a foam fus, it makes a very efficient insulator If this is the case, it may just be the thermal cut-out operating to save the ESC. Re-mount the ESC so that the flat side has plenty of air reaching it - the Bixler has quite a roomy fus so it shouldn't be too much of a problem. I often cut the heatshrink away from the flat side of the ESC, leaving the ali heatsink plate expeosed, which also helps with cooling.

Generally speaking, ESC's and motors tend not to get more than barely warm if they are working well within capacity. The battery pack will tend to get a bit warmer, tough, although once it gets hot, you should have a look at the C rating to see whether it is being exceeded.

I can't recall my amps draw at the moment but a 25A ESC with the original motor and spec prop should be fine. An essential item for leccy flight is a wattmeter, which will give you all the info you need.

Pete

[Steve McIntosh]

Thanks for the quick response

Yes Pete it was velcro'd onto the inside of the fuz by the flat side but when I was testing it in the house this afternoon I had it out of the plane altogether and it was still the same

[Chris Bott - Moderator]

How's the battery Steve? this could also be the culprit if something's not quite right with that.

Do you have more than one to try?

Are you balance charging? How much charge is going back in each time?

[Peter Beeney]

Steve, I had a similar situation on a Max Thrust Riot back in the summer, it was the ESC at fault and this was instantly exchanged for a new one without question… ….although how this would apply to Hobbyking I don’t know… it seems there are differing stories regarding guarantee returns…

If you get into electric a bit it’s nice to have one or two odd spare parts lying around, such as an ESC and motor. I find a quick substitution is usually the quickest way of proving a point; unless I'm certain I know what’s wrong. As it happens, I’d tend to think it’s not the motor overheating, if this is the case it’s most likely to run until something gives way, permanently! Also the ESC has to get pretty hot for a thermal shut down to occur, and this often includes the BEC, too, which results in an instant crash, and I’d consider that your timescales between stoppages for that are somewhat insufficient.

You have mentor by the sounds of it, if you’re a member of a club perhaps someone would be prepared to hook your ESC up to another motor to try it out? It would certainly give you good grounds for a return if you can establish exactly where the fault is.

In the first instance I think I’d be giving the ESC a kicking; It might conceivably be an iffy joint or some such, but if you give it a good shaking and knocking this might show itself.

Good Luck.

PB

[Chris Bott - Moderator]

To me it sounds like it's running fine then cutting out earlier than expected? Is that correct?

If it's running fine then it's unlikely to be the ESC or the motor.

Things that will make an ESC decide to reduce power and stop the motor, are either low battery voltage (Or an incorrect low voltage cutout setting) or high ESC temperature.

[fred clarke]

Ah, the pleasures of electric flight.

FWIW chasing down snags like this on an electric model are an absolute joy!

Please don't take this the wrong way but are you sure that the battery has not just simply run down. You seem to have got a 5 min flight; is this reasonable based on your battery size and current draw? A quick run with a watt meter should clear this up.

However, the symptoms you have described suggest (and I put it no stronger than that) that something is overheating. This, in turn, leads you suspect that too much current is being drawn for some reason. Alternatively, the battery may not be up to the task.

Thus, my approach to a problem like this would be to put a watt meter on the setup and see what current you are drawing and then checking to ensure that you are within the spec of the motor, esc and battery. Also, keep a close eye on the battery voltage to see how that is behaving. If the battery is on the way out you may see the voltage drop to around 9 - 9.5 volts, the motor stops as the low voltage cut out operates and then the battery recovers and you go through the whole cycle again albeit for a shorter time. If you can monitor each cell that will give you an even better picture of what is going on as you may just have a single cell playing up. Also can also monitor the esc and motor temp while doing this.

If all seems well with the wattmeter, then discharge the battery and charge on another charger and try that. If that doesn't help I would swap out the battery for a known good one.

If that doesn't solve the problem then swap out the esc for a known good one but use the original battery. The last item, IMHO, to suspect is the motor and swapping this out is the last thing to try.

If you still get the same symptoms having tried a different battery and esc then I would suspect lack of cooling.

Certainly, my experience is first to suspect the battery (even if it is brand new); in my experience they seem to give up the ghost with a whimper rather than a bang assuming they have not been physically damaged. The only problem I have ever had with an ESC (assuming it is still full of magic smoke) is that one particular one would not work properly with one particular motor. The only problem with a motor (other than crash damage) is that I over-propped it and it burnt out (totally avoidable and really, really irritating).

I must emphasis the above is what I would do and I do not claim it to be clever or the only way to do things. Its just an approach that I am comfortable with and has worked in the past. With a bit of luck someone else will chip in with a really simple solution and I will use that!!!

[WolstonFlyer]

It does sound like it might be the ESC at fault. Personally I would use a Turnigy Plush 30A ESC, the ones that I have seem to be very well made and a bit of extra 'overhead' in the current rating means that the ESC should never get overloaded and it should stay much cooler.

I try an allow at between 25% - 50% extra on the rating of the ESC on top of the maximum current drawn at full throttle when tested with a Watt meter.

[Piers Bowlan]

I would second what WolstonFlyer says. I would put my money on a duff ESC but check all the wiring for bad joints etc. I have good service from the Turnigy Plush ESCs too. There is no such thing as an ESC that is too big in my book! A watt meter is a good investment, I have had mine for years. Good luck sorting it out.

[Chris Bott - Moderator]

I can't see how a duff ESC would run for a couple of minutes every time and then die? If it's dead, it's dead.

My money is still on the battery. After that, overheating. or incorrect ESC programming.

[Andrew Russell 2]

Is the esc programmed correctly? Now that i think on it i had an esc that would do the same i think it was progammed for the wrong type of battery at the time

[Peter Beeney]

Chris, I know for certain sure that a faulty ESC can run intermittently, very much as Steve is describing. If the battery is going flat in my experience this quickly manifests itself by the power falling off initially, giving a distinct lack of urge, then the motor shuts down but will start again after closing and opening the throttle. However, this does not go on for very long, the motor soon stops completely until the battery is changed. The thermal cut off point is around the 150 degree C mark, that is finger blistering hot which is pretty obvious perhaps. I’ve only ever seen one really good example of this anyway, in some rather unusual circumstances.

The ESC relies on constantly receiving a valid signal to run the motor, if in some way this is getting changed or corrupted within the ESC on an irregular basis the motor will just stop and start in sympathy. This is one situation that might give these symptoms. Something that would be a bit difficult to check out, though, just substituting another ESC soon sorts it out.

Also Steve didn’t exactly say so, but is it possible he would have changed the battery anyway after his flight? I’d certainly consider that a regular pilot, his buddy instructor, would have considered this after a first flight of this nature. I certainly would, this would indicate a normal possible low battery state at this stage.

Anyway, I’m sure that Steve will find the answer, maybe he might like to post…

PB

[Steve McIntosh]

Thanks for all the advice guys.

To be fair we didn't change the battery after the first flight as my instructor put a wattmeter on the battery and said there was still 81% left in it.

Inexperienced as I am I still feel that it is the ESC that is it fault. The battery was balanced when charged and is brand new(mind everything is). I think I'm going to bite the bullet tomorrow and buy a new 30a ESC.

Will let you know

Steve

[Chris Bott - Moderator]

Well it could be the ESC, but in all the years I've been using them I've never seen or heard of one that would run, then stop, due to a fault. Then work again before stopping, every time.

Buying another will definitely help you diagnose this and will fix it if a) it's faulty and b) if there's a setting been changed like battery type or LVC level. It will also give you a spare for the future if it's not that.

If it were me, I'd be trying things like:-

• Running it with the prop off, see if it stops after the same sort of time.
• Running it with the wattmeter in circuit and watching the battery volts just before it cuts out.
• Charging the battery and trying again.
• Trying with a different battery. (One could show 81% and still be faulty).

[pete taylor]

+1 for trying the battery first.
They do recover after lvc and will exhibit the behavior you describe.

[PatMc]

It seems unikely to be the ESC & much more likely the battery. Makes more sense to get another battery before considering a new ESC, as having a spare battery would be more useful than a spare ESC.

What make, capacity etc is the battery that was used & do you already have another ?

[Piers Bowlan]

It seems unlikely to be the battery & much more likely to be the ESC . Steve, buy another battery AND ESC and if it turns out to be the motor then we are all wrong!

[fred clarke]

Steve

A few more thoughts for you:

Assuming that you have the stock motor fitted, the HK website recommends a 20 amp ESC - you have a 25 amp one thus you would seem to have plenty in hand!

If the ESC had a fundamental fault then I don't think it would restart. It seems to be shutting down prematurely.

One of two things will cause premature shut down of the ESC. Firstly, overheating. It will then enable you to carry on after it has cooled down. Secondly, it has reached low voltage cut out (lvc).

Herewith a simple test. Fly until the motor cuts, shut the throttle, count to ten slowly, reopen throttle, If the motor restarts then I would bet on lvc and a duff battery.

If it doesn't restart after 10 sec, shut throttle, count to 10 again, open throttle, etc etc. If it is lvc, the battery recovers quite quickly from an lvc but slower from an overtemp.

This feature is actually quite handy if the motor cuts at an inopportune moment - close throttle, count and, with a bit of luck, you'll get a few seconds power to help you out. Use this a lot when flying combat.

If you do want to buy bits then full steam ahead. Remember the old adage that the ideal number of models/motors/esc/batteries/rxs etc etc etc is one more than you all ready have. Repeat ad infinitum.

[gliggsy]

Hi fellas. Only ever having flown electric, my experience would be to check the three motor connectors,both male and female bullets, remove the heatshrink and check all soldered joints.

[Peter Beeney]

I think I’d be tempted to find out where the problem is first and just renew that item if necessary. If it’s something like an intermittent connection then it’s very inexpensive at least; and that would have to be between the ESC and motor anyway, so that limits any searching slightly. But it sounds as though Steve’s taken it apart and put it back together, so perhaps that does reduce those odds marginally. Also if he’s still using the same battery without charging then that would appear to say the wattmeter has a serious hangover… What are the odds on that?

As said, the similar problem to Steve’s I had was indeed the ESC, but I learnt not to speculate too much long ago. These things do sometimes have a habit of proving to be not quite what they seem in the first instance.

The final analysis will be interesting, but of course if a new ESC does cure it, it could still be an intermittent connection on one of the soldered ESC wire bullets or whatever is being used.

PB

[Steve McIntosh]

Again thanks guys

From what I am hearing would tend to suggest LVC is what I am seeing. I have a spare battery so will try that tomorrow and see if I am getting the same thing.

[Depron Daz]

We still don't know what size battery you were using, can you tell us?

[PatMc]

Make sure that it's fully charged & also fully charge the first one.

To sav risking the model you could run & time them on the ground, preferebly with a voltmeter attached to see at what the voltage is when the motor cuts.

[Piers Bowlan]

Steve, I take it you measured the voltage of each cell of the battery? (they should be pretty much the same). Have you got (or downloaded) the instructions which tell you if/how you can change the LVC setting of the ESC. It should also tell you how to change the ESC timing although I have never had to do that - yet.