SMALL - Telemetry SMALL - Radio
Thread Tools
Old Aug 23, 2015, 04:57 PM
pigmypuncher is offline
Find More Posts by pigmypuncher
Registered User
pigmypuncher's Avatar
United States, TX, Plano
Joined Oct 2010
283 Posts
Discussion
ESC - Any wayt to tell if an ESC is an OPTO variant or not?

This might be a stupid question, but.. Is there any way you can tell if an ESC is Optio or not just by looking at it?

The reason I ask is because either I've somehow managed to fry six of these BLHeli Slim ESC's (x6) (pics below), or they are all Optio - which means I've wasted a week trying voltmeters and internet searching.... Since I got them along with some other items in a project I purchased, I don't have the advantage of knowing who's ESC, or what model they are as there doesn't appear to be any distinguishing marks to help me ID.

Thanks in advance for any help!
pigmypuncher is offline Find More Posts by pigmypuncher
Last edited by pigmypuncher; Aug 25, 2015 at 08:43 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 23, 2015, 07:24 PM
Mike Dubovsky is offline
Find More Posts by Mike Dubovsky
Condescending Pedant
Joined Aug 2013
1,531 Posts
You left out a third possibility. They could be a non-opto isolated ESC without a BEC. One sure way to tell if they have a functioning BEC is to plug in the motor battery and check for around 5 volts on the red and black servo plug wires. If there is no voltage you will have to power your receiver with a separate battery or BEC.

You did not state what exactly your problem is. I am assuming that your receiver is not powering up or you are unable to control the ESC. A few more details of what your problem is would help with resolving it.
Mike Dubovsky is offline Find More Posts by Mike Dubovsky
Reply With Quote
Old Aug 24, 2015, 08:04 AM
JureZ is online now
Find More Posts by JureZ
Sokol
JureZ's Avatar
United States, CA, Palm Springs
Joined Jul 2013
533 Posts
if you have an Ohm meter, multimeter, etc,
you could measure the resistance between the battery return connection, and the servo plug return connection ( the black cable in each case ) .

they should be an open circuit in the case of an opto ESC.
they should be a short in a conventional ESC.
JureZ is online now Find More Posts by JureZ
Reply With Quote
Old Aug 24, 2015, 08:32 AM
pigmypuncher is offline
Find More Posts by pigmypuncher
Registered User
pigmypuncher's Avatar
United States, TX, Plano
Joined Oct 2010
283 Posts
My bad, I had initially put some of this info in the orig post, but after editing and rushing out the door for dinner, I failed to add it back - thanks for catching that!

I'm actually getting rather strange mV returns on the red/brown leads when the esc is powered by a known good 3S battery (same results if I use the main Black ground (power in) with the Red servo wire). The voltage meter starts off reading somewhere around 100 mV, then starts slowly climbing to around 400 mV then resets and starts over again (I've confirmed this behavior on 3 of 6 ESC (the other I just didn't bother testing with the volt meter since they also wouldn't power the FC) . I when ahead and re-confirmed those unusual readings again before posting.

I'll also add that I used a friends working quad's ESC by disconnecting his leads and jumping over to my Quad and had no issues - FC powered up and the voltage was around 5V (not seeing mV returns like I'm seeing on my ESCs). I'm confident the Volt Meter and my FC are working - just not sure if I've managed to Fry 5 esc when I soldered on longer leads, or if they are sans BEC and I only need to be worried about finding a BEC for the FC...

ETA - I would have thought that if OPTIO - V=0 on the red lead....
pigmypuncher is offline Find More Posts by pigmypuncher
Reply With Quote
Old Aug 24, 2015, 01:11 PM
Jinkslynx is offline
Find More Posts by Jinkslynx
Registered User
Norway
Joined Jan 2008
227 Posts
Your way of measuring is strange.
Measure resistance between the brown esc wire and the black battery wire without battery connected.

If opto, no connection.
If opto, esc need +5v on the red esc wire from your FC to power the opto circuit.

If connection, likely no bec.
Jinkslynx is offline Find More Posts by Jinkslynx
Reply With Quote
Old Aug 24, 2015, 03:22 PM
pigmypuncher is offline
Find More Posts by pigmypuncher
Registered User
pigmypuncher's Avatar
United States, TX, Plano
Joined Oct 2010
283 Posts
My approach was to see if any power was reaching the expected outputs. Without battery connected, and using the brown esc & black battery wire and my meter set to Ω, I get 0.0
pigmypuncher is offline Find More Posts by pigmypuncher
Reply With Quote
Old Aug 24, 2015, 03:27 PM
abenn is offline
Find More Posts by abenn
Registered User
Letchworth, Great Britain (UK)
Joined Jul 2004
12,903 Posts
Quote:
Originally Posted by pigmypuncher View Post
... I'm actually getting rather strange mV returns on the red/brown leads when the esc is powered by a known good 3S battery (same results if I use the main Black ground (power in) with the Red servo wire). The voltage meter starts off reading somewhere around 100 mV, then starts slowly climbing to around 400 mV then resets and starts over again ...
I think your readings suggest two things:- 1. The ESCs are not opto, because you're getting the same behaviour if you read voltage between the red and brown receiver connection, and the red receiver connection and the black input wire. That suggests to me that the black input wire and the receiver brown wire are connected, which means the ESCs are not opto-isolated; and 2, I suspect that the small mV readings you're getting are just random "noise", and that there's no BEC in the ESCs. Edit: You've just confirmed they're not opto by the reading you've given in post #6.

You can test them out by supplying 5v to the receiver from a NiMh receiver pack, or from a stand-alone BEC. The receiver should then power up, and the ESCs should run the motors correctly.
abenn is offline Find More Posts by abenn
Reply With Quote
Old Aug 24, 2015, 05:01 PM
pigmypuncher is offline
Find More Posts by pigmypuncher
Registered User
pigmypuncher's Avatar
United States, TX, Plano
Joined Oct 2010
283 Posts
thanks again for the replies, I'm definitely getting a better grasp of ESCs beyond just the thingy that controls the motor speed. I agree with your conclusion abenn (and am somewhat embarrassed I didn't realize it myself before posting) - the optic conversion of the signal would isolate the servo lead and thus the resulting output on the voltmeter would have to read Zero for it to be a functioning Opto ESC (this of course is assuming the ESC works and hasn't been damaged). I think I got too focused on the 5v output instead of the connectivity of the circuit. Cart/Horse

So, that leaves me with either a functional ESC that has no BEC (which is probably the case here), or multiple cooked ESCs. With the props remaining off, If I use a UBEC to power the FC as you suggested; and the motors spin up - are there any other tests I can use to confirm the ESCs are working correctly or are they typically all/nothing in function?
pigmypuncher is offline Find More Posts by pigmypuncher
Reply With Quote
Old Aug 24, 2015, 05:12 PM
C₄H₁₀ is offline
Find More Posts by C₄H₁₀
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, MN, Minneapolis
Joined Aug 2009
12,997 Posts
They're multicopter-specific ESCs. They do not have built-in BECs.
C₄H₁₀ is offline Find More Posts by C₄H₁₀
Reply With Quote
Old Aug 25, 2015, 01:58 AM
abenn is offline
Find More Posts by abenn
Registered User
Letchworth, Great Britain (UK)
Joined Jul 2004
12,903 Posts
Quote:
Originally Posted by pigmypuncher View Post
... So, that leaves me with either a functional ESC that has no BEC (which is probably the case here), or multiple cooked ESCs. With the props remaining off, If I use a UBEC to power the FC as you suggested; and the motors spin up - are there any other tests I can use to confirm the ESCs are working correctly or are they typically all/nothing in function?
With power to the receiver the ESCs will either work or they won't. Test them one at a time, connected directly to the receiver's throttle channel. I don't think there's any other tests you can do, other than observing how the motors run. A wattmeter on the battery leads will allow you to see what's going on.
abenn is offline Find More Posts by abenn
Reply With Quote
Old Aug 25, 2015, 03:12 AM
GordonTarling is offline
Find More Posts by GordonTarling
Supersonic Engineering
GordonTarling's Avatar
UK, Greater London, Uxbridge
Joined Mar 2001
3,308 Posts
There are now many 'opto' ESC's on the market which are not opto at all, just that they don't have BEC. I think that yours fall into this category. As others have said, supply independent power to the FC and receiver and see if the ESC's work then.
GordonTarling is offline Find More Posts by GordonTarling
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion if the point is a "living wage" ... better not stop at 15 an hour ... logan5 Life, The Universe, and Politics 2 May 29, 2015 09:20 AM
Discussion Spektrum Dx6i -- how to tell if the cahrger is working or not byrocat Radios 1 May 25, 2013 10:51 AM
Discussion How do you tell if a PM has been read or not? Jonathan Ott Site Chat 4 Nov 28, 2010 07:23 AM
Discussion Can't tell if my motor's running or not NoFlyZone Beginner Training Area (Aircraft-Electric) 13 Oct 12, 2006 01:48 PM
Question How to tell if my 430L is threaded or not??? Twistedblades Mini Helis 8 Mar 17, 2006 10:39 AM