Align RCE-BL80X ESC bec????

[stocksy27]

hi
just built my trex 500x combo and on the bench can get it to "brownout" all the time running the stock esc and built in bec at 7.2v, am i going to need to optigaurd or 2s lipo or will running at 8.4 or 6v bec make it more reliable?

thanks

[coolice]

hi
just built my trex 500x combo and on the bench can get it to "brownout" all the time running the stock esc and built in bec at 7.2v, am i going to need to optigaurd or 2s lipo or will running at 8.4 or 6v bec make it more reliable?

thanks

Hey buddy.

Off the top of my head the 500X comes with the Align branded Hobbywing ESC (on closer inspection it might not be, think the HW ones start at 10amps and up) but the 80x is still capable, with a decent enough BEC for this size model for all but the hardest of 3D. Certainly shouldn't struggle on the bench that's for sure.
Having said this I did have one 500X I setup for a customer that just wouldn't turn the motor or arm from memory, which wasn't good for a new out the packet ESC.

If you can induce a brown out on the bench I'd more than likely assume binding but unlikely, a dodgy servo or a faulty ESC in general.
Have you tried unplugging one servo at a time to try and eliminate this idea? Got nothing to loose by trying.
Also do any of the servos feel abnormally warm? A sign something isn't quite right.

Ian Contessa

[Grumpy]

The Trex 500X has a choice of two different ESCs. The 'basic' 500X version comes with the BL80X which is Align's own ESC. The more costly versions of the 500X come with the BL80A which is a Hobbywing re-brand. The Hobbywing version has a bulletproof BEC but i cant vouch for the BEC in the BL80X, based on it's claimed rating it 'should be' ok.

Check that none of the servos are binding, a binding servo will pull down even a good BEC. You might also try adding a capacitor into a spare port on the FBL. A 10V or 16V 4700uf cap should do the job, a pair of them is even better: YGE 90/120LV 5,7V 6/12A BEC with capacitors | VStabi

[stocksy27]

thanks guys , ive set it all up and ran it at 6v 7.2v and 8.4v all do the same although does it more on 8.4v servos and swash all fine no binding at all, will try a capacitor however is does not say i need this when i bought the trex combo haha.

[coolice]

thanks guys , ive set it all up and ran it at 6v 7.2v and 8.4v all do the same although does it more on 8.4v servos and swash all fine no binding at all, will try a capacitor however is does not say i need this when i bought the trex combo haha.

Hey buddy.

You're welcome.

Sadly a capacitor isn't going to help in this situation and in reality is not needed with a solid BEC.
Ultimately there is an underlying problem there I think as without flight loads/airframe movement inducing gyro commands to the servos, the amp draw is very low on the bench.
A capacitor is only able to offer a little protection to minor short drops in voltage, so should only be treated as a power smoothing addition rather than a fix.

As you mention the ESC seems to power the setup better on 8.4 volts than a lower voltage, it seems to me to highlight the inbuilt BEC is at fault. As it's a switching BEC so can't cope with the demands.
I had a similar fault years ago with a CC ICE 100 amp esc, on paper the BEC was good, but on certain output voltages it just couldn't power the servos and they went nuts.

Do you have another power source you can connect to the beastx in place of the ESC for now to test all servos move as desired?
Is the kit/ESC new so you could return the ESC for testing/replacement?

Ian Contessa

[Grumpy]

Not sure about the cap not working Ian. If you check Mikado's testing they do work in many situations apparently identical to this.. As they cost about 20p it's worth a try at least before trying more expensive options. FWIW the genuine retail boxed Hobbywing ESC comes with a cap for exactly this purpose. Sometimes it's not the fault of the BEC a such it's back EMF generated by the servos.

[stocksy27]

yes i have a lipo i could use and a jive esc with logging so will pop that on and see what the servos are actually pulling but does seem the esc is a fault here, all new from a kit yes so hopefully they will sort me a esc out.

thanks

Hey buddy.

You're welcome.

Sadly a capacitor isn't going to help in this situation and in reality is not needed with a solid BEC.
Ultimately there is an underlying problem there I think as without flight loads/airframe movement inducing gyro commands to the servos, the amp draw is very low on the bench.
A capacitor is only able to offer a little protection to minor short drops in voltage, so should only be treated as a power smoothing addition rather than a fix.

As you mention the ESC seems to power the setup better on 8.4 volts than a lower voltage, it seems to me to highlight the inbuilt BEC is at fault. As it's a switching BEC so can't cope with the demands.
I had a similar fault years ago with a CC ICE 100 amp esc, on paper the BEC was good, but on certain output voltages it just couldn't power the servos and they went nuts.

Do you have another power source you can connect to the beastx in place of the ESC for now to test all servos move as desired?
Is the kit/ESC new so you could return the ESC for testing/replacement?

Ian Contessa

[coolice]

Not sure about the cap not working Ian. If you check Mikado's testing they do work in many situations apparently identical to this.. As they cost about 20p it's worth a try at least before trying more expensive options. FWIW the genuine retail boxed Hobbywing ESC comes with a cap for exactly this purpose. Sometimes it's not the fault of the BEC a such it's back EMF generated by the servos.

Good morning.

Ah see now you're onto a different topic with back EMF and is a total different issue and not one solved by the addition of a capacitor.

A capacitor is a smoothing device, in this case it works with electricity and acts as a small battery in effect that charges/discharges very quickly to cope with sudden demands in power. Hence the capacitors on ESC's to smooth out current ripples and CC's Cap Bank to help with ripple voltages during slow spool up.
Thus as per Mikado testing above, small voltage drops in flight can be smoothed with this power reserve, but we are talking very small drops with the size of capacitor mentioned.

Back EMF is an electrical charge/interference that can be generated by the DC motors in our case, that can then travel back into other electronics.
However a capacitor isn't going to stop this, a diode would do this. Indeed a few years back now the odd back EMF story highlighted that the Mikado Mini Vbar was missing a diode that the full size Vbar has fitted and thus couldn't deal with back EMF so well. Assuming my recollection of this is right, as I've not seen any further talk to provide truth to the matter.

However in all my years I am yet to experience any back EMF issues especially with Align servos, over on Helifreak there was a topic that, if I recall directly, did list some know servos that did/could give an issue.

However by all means try a capacitor, but I think it's clutching at straws based on what we know.
As I said above, as the problem is present even before flight loads are applied, you're gonna need a jolly big capacitor to bolster that current drop :-)

Also let's be honest, with the amount of Align models sold all over the world, we'd have heard about back EMF issues by now if there were any.

Ian Contessa

[coolice]

yes i have a lipo i could use and a jive esc with logging so will pop that on and see what the servos are actually pulling but does seem the esc is a fault here, all new from a kit yes so hopefully they will sort me a esc out.

thanks

Morning mate.

Ah good man, that's what I was hoping to hear so you could not only eliminate things but also perhaps go onto enjoying the new model.

I appreciate all that's being said, but as you're problem is present even before flying, I'd be reluctant to even try and mask the fault.
Keep us posted buddy.

Ian

[Grumpy]

Fwiw Mikado also did testing with caps to address back emf and they proved effective. The testing is on Mikados site. The cap smooths both dips and spikes in voltage. Yes, the charge they store is tiny but testing shows it to be enough to resolve many of these issues. If it works in this case I can't say but if it were me for 20p I'd try one. Like I said, Hobbywing actually supply a cap with their ESC which must say something about their effectiveness?
Obviouly though if it's suspected that the ESC is faulty a cap isn't the answer. if the shop you got it from will replace it then fair enough but I suspect that if you replace it with another identical ESC the problem will remain

[coolice]

Fwiw Mikado also did testing with caps to address back emf and they proved effective. The testing is on Mikados site. The cap smooths both dips and spikes in voltage. Yes, the charge they store is tiny but testing shows it to be enough to resolve many of these issues. If it works in this case I can't say but if it were me for 20p I'd try one. Like I said, Hobbywing actually supply a cap with their ESC which must say something about their effectiveness?
Obviouly though if it's suspected that the ESC is faulty a cap isn't the answer. if the shop you got it from will replace it then fair enough but I suspect that if you replace it with another identical ESC the problem will remain

I don't understand why we're still discussing caps as a potential fix when clearly we're not even at the point where back emf or a voltage dip can be attributed to the problem.
The models not even left the ground to provide any feed back to hint at a sub-standard power supply. In fact it just cannot sustain any form of stable flight surface movement on the bench if I'm reading it right, so to me that screams a BEC issue (caused by it either being faulty or a duff servo even tripping up the BEC) and thus is not something that can be fixed with a 20p capacitor as you say.

In the interest of being open to new ideas I've re-read the linked aricle and it's detailing the pitch pump set to 100 and a flight being made to determine the voltage drop. Again this proves we're far away from this step to even consider a capacitor.

We can bury ours mind in all the BS of what can have an effect without thinking about it for ourselves, or we can draw on years of experience and deal with it in a methodical way which is to eliminate potential causes one by one.

For reference I'm using an Align branded HW ESC in my 550X, it didn't come with an Rx/FBL capacitor and is working fine.

As above I'm yet to hear of any back emf issues with Align servos and/or the beastx in general. Likewise the Vbar, I've flown one for years even on 35mhz and not experienced a single concern.

The stocksy27 is doing it right by swapping out the potential root cause and not getting baffled by the information that isn't really relevant yet.

Ian Contessa

[Grumpy]

Ian,

We are both trying to help here so I dont want to get drawn into an argument. I'll let an actual ESC manufacturer have last say, here I'm just quoting what the instruction leaflet that comes with the Hobbywing 80A ESC says on the subject of use of the supplied capacitor, and Stocksy can judge if that seems to be relevant in this case:

(Sorry for the Chinglish, but it's quoted word for word)

How to judge if an external cappack is needed
Electric helicopter users can enable the throttle cut and quickly move around the stick controls pitch and stick controls direction to prompltly and repeatedly turn on/off the servo and switch direction and see if the FBL system (i.e. Vbar) re-starts during this process. It indicates that the peak load of the electronic system exceeds the output capacity of the BEC and an external cappack is needed if the FBL is restarted

Here's a pic of the manual and the cap that came with my Hobbywing 80A ESC so you can see that I'm not BS'ing anyone:

[coolice]

Ian,

We are both trying to help here so I dont want to get drawn into an argument. I'll let an actual ESC manufacturer have last say, here I'm just quoting what the instruction leaflet that comes with the Hobbywing 80A ESC says on the subject of use of the supplied capacitor, and Stocksy can judge if that seems to be relevant in this case:

(Sorry for the Chinglish, but it's quoted word for word)



Here's a pic of the manual and the cap that came with my Hobbywing 80A ESC so you can see that I'm not BS'ing anyone:

I appreciate you're trying to help, however I can't help but feel you're hung up on the capacitor idea, which I'll agree shows slight benefits in the real world situations, but it is not a miracle worker.

Why don't you start another topic and link to the various posts with the information about BEC supply smoothing/bolstering for people to read? It would be much better to drum up a discussion over.

I did go over the Mikado tests yesterday and saw anywhere from a 0.8 volt drop at 5.7 volts BEC setting to a 2 volt drop at higher BEC outputs, with a 1 volt saving using a cap at the higher voltages. However again all tested with a 100% pitch pump setting and taken while flying, neither of which we are currently at.
As an aside, I seem to recall a parameter with the Align FBL units stating that higher values set here than X percentage, would require the user to make sure their BEC is up to the task. It's been a while since I used an Align unit so I can't recall the actual parameter.

Looking at the evidence so far if the BEC output is set to 7+ volts and it's dropping on the bench tests to less than 3.5 volts (or brownout voltages 3.3V and less usually from tests conducted) then a drop of 4 volts isn't going to be smoothed by a capacitor any time soon.

Ian Contessa

[Grumpy]

Ian, I'm not for one minute suggesting that a capacitor is a 'silver bullet' that will solve every problem. What I am pointing out is that they are specifically recommended by a reputable ESC manufacturer for exactly this problem and at bout .20p for a capacitor I think it's worth a try... No? They have worked for me in the past and now I usually fit them as a matter of course because they cost nothing and cant do any harm.

Of course, if it doesn't work then move on and look at other options. At this point though there is IMHO no evidence of a faulty ESC, so talk of replacing it or sending it back seems a bit premature to me.

[Grumpy]

PS.. Stocksy,

What FBL and receiver are you using? A flying buddy had endless troubles running Speky sats off a Bavarian Demon. Tried everything to fix it, capacitors, new ESC, stand alone high rated BEC, nothing worked. In the end it turned out that it's a known issue with the Demon, it cant supply stable power to sat receivers, so you have to use a stand alone conventional receiver.