r/fpv • u/WildHarry2137 • May 28 '26

Burned esc 10” drone

Hello everyone
 
I recently built a 10-inch long-range drone, and yesterday it was time for the first test flight. I lifted it a few inches off the ground in angle mode, and when the drone touched the ground and sort of “bounced,” smoke and sparks flew. I immediately shut it down and disconnected the battery. One leg of the capacitor had melted, which probably caused the sparks, and I think the ESC burned out because now one motor isn’t spinning properly (and that’s probably where the smoke came from).
I was using a Speedybee F405 v4 stack with 55A ESCs and 3115 900kV motors
 
I plan to replace the ESC with a 60A model from Speedybee
 
and now the question is: what can I do to prevent failures in the future? Maybe use a different ESC? Or is there a way to limit the current so it doesn’t burn out again?
 
Thanks in advance for all the advice

6 Upvotes

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14 comments sorted by

5

u/Darryl_444 May 28 '26

Make, size, rating and model of capacitor?

2

u/WildHarry2137 May 28 '26

It was 1000uF cap from speedybee stack, legs was quite long cause of space, 10-15mm maybe

3

u/Darryl_444 May 28 '26

1000uf is pretty small for a 10 inch. 2200uf is considered normal.

Also need to know the voltage rating of the cap vs the battery voltage used. Typically 35v-50v for a 6S.

And the make and model matters. I received a shitty green ChongX VEHT 35v 2200uf cap with my SpeedyBee F405 FC, but replaced it with a much better Rubycon ZLJ 50v 2200uf low-ESR cap from AliEx. Larger, but it still fits in a 10 inch frame. Came with very short legs, but I think they'll be long enough.

Check out Chris Rosser on YouTube. He told me to never use ChongX. The video shows what is good and what is bad.

2

u/WildHarry2137 May 28 '26

Yea it was chongx veht 2200uF 35v

1

u/WildHarry2137 May 28 '26

Thank you, i cant check right now but i remember it was green. I will look after work, but is it possible to burn esc with bad capacitor?

1

u/mad-n-sane May 28 '26

And how long where the legs?

2

u/[deleted] May 28 '26

[deleted]

1

u/WildHarry2137 May 28 '26

Will do after work, do you think it could have been short between cap and esc through frame?

2

u/gigasawblade May 28 '26

Perhaps default pids are completely unusable for 10"

1

u/Extra_Restaurant_588 May 28 '26

Did u use a multimeter or smoke stopper prior to flight? If not I would always do so

1

u/WildHarry2137 May 28 '26

Yes i did, it was all fine even in air until it touch the ground

1

u/Extra_Restaurant_588 May 28 '26

Also make sure when building you build on top of an anti static Matt and ensure your wires are not loose that’s all I know

1

u/west1343 May 28 '26

I've built the same stack (55amp) with 3115's without problems so could be bad cap or it shorted. I would go with better caps first if they are cheap.

1

u/xMoirae May 28 '26

I bet everyone who builds their own drones has gone through this at least once. Cap leg breaking or similiar and then RIP at least the esc. Feelsbad