Thanks Glen.

About attaching additional caps onto the circuit, I wonder if it is ok to attach a big one near the battery side (just after the safety link, before the wires split up to go to different ESCs) as I don't have much room left in the ESC compartment. I would also like to ask if adding too much cap would do damage to the circuit. I'm currently looking at a 5600microF cap, in comparison the brushless ESCs have two 560microF caps.

you want the caps as close to the ESC's as possible. Part of the issue is caused by the actual length of wire itself. If you can't fit big ones in near the ESC put in whatever will fit there then bigger ones further down the line.

Oh when you are posting images to make them less huge try putting a l or h (large or huge thumbnail size) after the imgur link. so imgur.com/xxxx.jpg becomes imgur.com/xxxxh.jpg
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Mechanical engineers build weapons, civil engineers build targets

Thanks Valen.

I wonder when looking for caps do I focus more on capacitance or voltage? It's kinda hard for me to find caps that can arrive before the event so not sure if I will find the perfect cap.

EDIT: Ah nevermind... I was stupid enough to not know how to flip pages on JayCar's website. I've bought a few 440ufs to add close to the ESCs, and 1000uf to be on the main power line.

You definitely need a cap with a higher voltage then the battery; there is some ratio, maybe 1.5 or 2 times the supply voltage to be safe. After that a capacitor with a high current ripple rating or a low ESR ( basically the same thing) is an advantage but not essential.

If you can't find something suitable at Jaycar, try RS Components or Element 14. Something like this should work and RS can ship next day for free: http://au.rs-online.com/web/p/aluminium-capacitors/6841999/
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Thanks Nick.

Very bad news:
I just added some extra caps to the system. I checked that the new caps' negative markings are facing the circuit's negative, but when I did the test with one drive ESC plugged in, the drive ESC and the receiver smoked immediately (I had no problem with this setup before.). How did that happen?

Having the caps around the wrong way should only destroy the caps (very loudly!) so they are not likely to be the problem. If the receiver also blew up, it means the ESC's BEC failed and delivered more than its regulated 5 or 6 volts. BECs usually just shut down when they fail but can also fuse and deliver the full battery voltage.

Assuming you didn't do anything wrong, I suspect the ESCs are either faulty or are not capable of running at 6S. Its rare but not unheard of for manufacturers to overstate the capabilities; usually its just the current. Do you have a link to the ESC's product page? ALso, what motor is it driving?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I'm running the Botbitz 30A ESCs driving 775 motors. I don't know why I just can't access the page today.

I think the ESCs themselves are just fine because I never had a problem with them before without the extra caps on.

To elaborate on that, I added a few caps very close to the ESCs, a few caps on the other branch of the circuit which was empty (usually would hold ESCs on the other side of the bot) during the test, and a bigger one closer to the battery. These added caps seemed just fine when I plugged in the safety link.

Also, the ESC was meant to twitch the motor three times when starting, and it actually did that when testing while emitting smoke.

Hmm, plenty of builders have used the 30A ESCs and they are definitely rated for 6S voltages so that's not the problem. What was the time-line from when you powered the bot up? Did the ESC smoke immediately or not until you applied some throttle?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Oh god I forgot to mention that the ESC also had a pop sound when powering on (might have been a cap in the ESC).

When I plugged on, the pop sound and smoke came almost immediately. I didn't even have time to touch the throttle. That said, when the ESC powers on, it has this weird routine that it would twitch the motor three times. I guess that could be called some form of a throttle.

EDIT: The ESC twitched the motor just fine. Not sure if that's a sign of it being OK to drive the motor though.

Last edited by MoonSet416 on Sat Aug 12, 2017 3:48 pm; edited 1 time in total

Can you show us a pic of the whole rig? Any maybe a diagram of what's connected to what?

OK, So if the motor twitched 3 times but didn't get any throttle, that means the ESC output isn't shorted and the ESC didn't burn up from too much current draw. It *probably* also rules out having the supply voltage reversed.

What is the Lipo battery model?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Sure, just when I was trying to take a photo I realized that the drive ESC used as a BEC in the previous test and the ESC used for this one both have a hole on the heatshrink.

The rig. (wherever there's a bunch of tape there's an added capacitor underneath.)



The hole on the heatshrink.



The ESC from the other day without the heatshrink. (today's ESC is just like this one, but the small capacitor on it did not seem blown.)



This is where both of the ESCs broke. (the exact same pin on the exact same IC)



This is the 16V cap from the earlier ESC.



This is the same cap from today.

To Nick:
Turnigy nano-tech 6000mah 6S 25~50C Lipo Pack

Also some added sidenote: I have tested with all four ESCs connected (without any load and without any added caps), and that time the setup worked just fine.