• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Hobbyking ESC Confusion

#1
Hello everybody.

I'm currently building a micro quadcopter, and I've run into a bit of confusion and I'm struggling to find the information I'm looking for. I bought four of these components, believing them to be 6A ESCs I could use for my quadcopter. However, by looking up the abbreviation 'UBEC', I'm now worried that these aren't ESCs at all. Could somebody please clarify for me what these components are?

Thanks in advance.
 

Tritium

Amateur Extra Class K5TWM
#3
They are ESC's (Brushless Motor Speed Controllers). They will supply up to 6A to a brushless motor. Your clue to identification is that there are 2 wires in and 3 wires out. This shows it is a speed controller. A true UBEC has 2 wires in and 2 wires out and ONLY changes a higher to a lower voltage, usually 6 to 3.3V output.

Thurmond
 
Last edited:
#4
Ah good, thanks for the help! I was starting to panic, as I've already soldered them to my quad frame and removing them would have been a pain if they turned out to be the incorrect component. Another question I have is that since I'm using a LiPo battery, I realised that I'd have to reprogram my ESCs to not cutoff with low voltage to avoid my quad crashing, but that I'd also need to have a LiPo Alarm attached to the battery during flight to ensure that I don't damage my battery by over-discharging it. How do I connect the alarm? My battery has two leads, one for the main power which will be connected to the power leads for my ESCs and one to be plugged into the receiver to power that and the control board.

My question is that how do I plug in both the receiver and the alarm to the battery? I assume I'll need some kind of cable splitter, but I've been unable to find one anywhere. Thanks in advance.
 

Ak Flyer

Fly the wings off
Mentor
#7
through the receiver plug on the esc which is the red white and black lead coming out of the left in the picture, next to the battery leads. You plug that in to control the esc and that's also how the esc feeds the receiver and servos is you had any.
 
#8
Oh, I didn't think of that! So basically, my ESCs will feed power through their 3-wire cables into my control board, and then the cables from the control board to the receiver will also power the receiver?
 
Last edited:

colorex

Rotor Riot!
Mentor
#9
Oh, I didn't think of that! So basically, my ESCs will feed wire through their 3-wire cables into my control board, and then the cables from the control board to the receiver will also power the receiver?
Exactly! Took me a while too to figure that out. :)
 
#10
#11
So basically, my ESCs will feed power through their 3-wire cables into my control board, and then the cables from the control board to the receiver will also power the receiver?
Confusing, right? That's not how you normally "do stuff". Also, it can give you problems if you connect several speed controllers each providing its own power. Haven't tried that myself, but the advice is to disconnect the red wire from all but one if you have several power sources.

The BEC on that ESC is quite weak. Measure (and/or do the math) on the power consumption of your controller and rx. Perhaps you should get a separate BEC and disconnect power from all ESCs. But it wont hurt to try, unless you try to fly. Replace props with tape first.

Regarding low voltage: If you set the low voltage level to 3.2 (high) you can use "reduce power" as action instead of cut-off. Combining with a beeper and tx timer is good too, but maybe you won't hear the beeper if you're far away.
 
#12
Confusing, right? That's not how you normally "do stuff". Also, it can give you problems if you connect several speed controllers each providing its own power. Haven't tried that myself, but the advice is to disconnect the red wire from all but one if you have several power sources.

The BEC on that ESC is quite weak. Measure (and/or do the math) on the power consumption of your controller and rx. Perhaps you should get a separate BEC and disconnect power from all ESCs. But it wont hurt to try, unless you try to fly. Replace props with tape first.

Regarding low voltage: If you set the low voltage level to 3.2 (high) you can use "reduce power" as action instead of cut-off. Combining with a beeper and tx timer is good too, but maybe you won't hear the beeper if you're far away.
Well as it's a quadcopter, I'll be plugging 4 ESCs into the Hobbyking Multi-rotor Control Board, so is it the case that I'm going to have to remove the red wire from the servo leads on all but one of the ESCs, in order to not supply more power than the control board needs? I'd rather find out before I do anything, because I don't want to end up either frying my board with too much power from the ESCs or cutting the power leads and not having enough power for either the control board or the receiver.

Concerning the low voltage issue, I've now reprogrammed my ESCs to NiCad mode so that they won't do anything with low voltage. I'll have my LiPo alarm connected during flight which flashes a light and beeps when voltage is low, that should be fine as I probably won't be flying it too far away from myself.

Also, I'm not sure of the power consumption of my RX module (this one), it doesn't say anything on the page and I'm not sure how to measure it. My control board takes voltages between 3.3V and 5.5V so that shouldn't be a problem if the BECs are 5V, should it? And I would have thought that 0.5A would be plenty of current for these small devices. This is a lot more complicated than I first thought! D:
 
Last edited:
#13
Well as it's a quadcopter, I'll be plugging 4 ESCs into the Hobbyking Multi-rotor Control Board, so is it the case that I'm going to have to remove the red wire from the servo leads on all but one of the ESCs, in order to not supply more power than the control board needs? I'd rather find out before I do anything, because I don't want to end up either frying my board with too much power from the ESCs or cutting the power leads and not having enough power for either the control board or the receiver.
My control board takes voltages between 3.3V and 5.5V so that shouldn't be a problem if the BECs are 5V, should it? And I would have thought that 0.5A would be plenty of current for these small devices.
You cannot get too much power to your control board unless the providing ESC (or BEC) delivers too high voltage (in which case they're faulty or incorrectly configured). Also, it is considered a bad thing to parallel several BECs (built in or dedicated) to power the same unit. As it's a quad, you're not powering anything but your rx and control board from the BEC, so you'll most probably be ok with the power from one of the ESCs BECs. As the control board also handles low voltage I don't see any problem unless your rx is very sensitive.

Also, I'm not sure of the power consumption of my RX module (this one), it doesn't say anything on the page and I'm not sure how to measure it. This is a lot more complicated than I first thought! D:
You can use an amp meter to check, just connect it in series with the ESCs positive or negative control lead. Should the current from one BEC still not be enough, there's also the option to route one ESC's BEC to your rx, and another to your control board, but that'd require cutting the power cords between the rx and the control board and then I'd rather go with a dedicated BEC.

If voltage and current issues are a bit confusing, check out Colorex excellent article for some of the basics. If not, my apologies.

Concerning the low voltage issue, I've now reprogrammed my ESCs to NiCad mode so that they won't do anything with low voltage. I'll have my LiPo alarm connected during flight which flashes a light and beeps when voltage is low, that should be fine as I probably won't be flying it too far away from myself.
That should also work, of course. It's a balance between the safety of the craft, of its batteries and of your surroundings =). Once below 3v the batteries will drop like a stone so keep some headroom... If your rx/tx already supports telemetry, that'd be the optimal solution that'd let you get some more distance later on.
 
#14
You can use an amp meter to check, just connect it in series with the ESCs positive or negative control lead. Should the current from one BEC still not be enough, there's also the option to route one ESC's BEC to your rx, and another to your control board, but that'd require cutting the power cords between the rx and the control board and then I'd rather go with a dedicated BEC.
Thanks for all your help, you've cleared a lot of things up for me. But there's just this issue of ensuring that the BEC of a single one of my ESCs will be sufficient to power my RX unit. So I understand that I can measure the current being drawn by it if I connect a multimeter in a series circuit with one of my ESCs, my battery and my RX unit. But how will I know if the RX is receiving enough power? I know that Power = Voltage x Current, so I assume I should multiply the voltage of the BEC by the current drawn by the RX unit, but what will this tell me? Again, thanks in advance!
 

Tritium

Amateur Extra Class K5TWM
#15
Unless you are running servos (and your not on a quad) then you need not worry about the BEC rating at all as a general rule. I have NEVER seen an ESC with built in BEC not able to power the receiver and control board combination on a quad.

Thurmond
 

tramsgar

Senior Member
#16
But how will I know if the RX is receiving enough power? I know that Power = Voltage x Current, so I assume I should multiply the voltage of the BEC by the current drawn by the RX unit, but what will this tell me? Again, thanks in advance!
Voltage and current behaves a bit different but are still intimately connected. Simplified, you could say that current is drawn and voltage is provided. When you power something, it draws current. When current is drawn, voltage will go down if the power source (here the BEC) cannot compensate for that to keep the voltage up. So, an ideal 5 V BEC rated for 500 mA will allow 500 mA to be drawn without voltage dropping below 5 V. If you draw more than it is rated for (or if it does not live up to its spec) the voltage will go down, and that's what you'll see when you measure. So, to be sure, do this:

1. Hook up you equipment and measure current draw (multimeter in series). It should not go above what the BEC is rated for.
2. Measure the voltage (multimeter in parallel on consuming device) and make sure it is not lower than the device's rated min voltage.
3. Do a range test! Make sure it works even when a lot of input is given and the battery is about to run out.

Tritium is correct in what's been established: no servos = power probably enough.