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-   -   Domed / blown capacitors (https://www.rctech.net/forum/radio-electronics/1102009-domed-blown-capacitors.html)

Sir 51D3WAYS 07-22-2022 03:29 AM

Domed / blown capacitors
 
I've noticed that one of my 8th scale ESCs (HW XR8 SCT) domed it's capacitors on the 2nd run out. Is this due to excessive current draw or heat? Manufacturing defect? I run the included ESC fan, none on the motor, it doesn't get too hot. ESC does thermal without a fan though.

Can I just solder a pre made cap bank to the positive and negative terminals of my esc to substitute/relieve the stress?
I do run long battery leads. (Battery came that way and I'm too lazy to shorten them.) I've run long battery leads on an ARRMA Mojave before, stock ARRMA ESC never had an issue.

FWIW, the XR8 replaces a XERun SCT Pro that let out the magic smoke from it's caps as well (spectacularly) due to a tiny stone jamming the gears.

All this on 4s.

gigaplex 07-22-2022 05:16 AM

Leaving the bad capacitors in circuit can lead to problems. If it failed after 2 runs, that suggests a manufacturing fault.

the rc guy 07-22-2022 07:54 AM

you cant just point at manufacturers fault without knowing battery .. you can add a cap block but remove domed caps

GerryH 07-23-2022 01:38 PM

If you're good with a soldering iron, disassemble the ESC case and replace the capacitors. You should be able to get their specs off the side. Just remember to put the new ones back in with the correct polarity.

Most likely heat damage. But it's pretty usual to have it go bad on the 2nd run. The ESC fan should provide cooling, but if there's debris between the caps and the fan, that could contribute.

elk 07-25-2022 07:19 AM


Originally Posted by Sir 51D3WAYS (Post 15922951)
>ESC does thermal without a fan though.

>FWIW, the XR8 replaces a XERun SCT Pro that let out the magic smoke from it's caps as well (spectacularly) due to a tiny stone jamming the gears.

Just to clarify, were you saying that this particular ESC has thermaled, leading to possible cap damage? Also, if this is the same vehicle, is it possible that a similar situation occurred as before?

RacingRookie27 07-25-2022 08:49 AM

Do you have a picture?

Sir 51D3WAYS 07-26-2022 06:39 PM


Originally Posted by the rc guy (Post 15923010)
you cant just point at manufacturers fault without knowing battery .. you can add a cap block but remove domed caps

2x 2s Gaoneng 5200mah 90C


Originally Posted by GerryH (Post 15923351)
If you're good with a soldering iron, disassemble the ESC case and replace the capacitors. You should be able to get their specs off the side. Just remember to put the new ones back in with the correct polarity.

Most likely heat damage. But it's pretty usual to have it go bad on the 2nd run. The ESC fan should provide cooling, but if there's debris between the caps and the fan, that could contribute.

Possible that there was some debris...


Originally Posted by elk (Post 15923794)
Just to clarify, were you saying that this particular ESC has thermaled, leading to possible cap damage? Also, if this is the same vehicle, is it possible that a similar situation occurred as before?

yes and same vehicle. Don't think so.

I have a HW MAX10 SCT combo in a very heavy SCT, and that has been beaten senseless and still works. I think the caps on that are domed too.


Originally Posted by RacingRookie27 (Post 15923838)
Do you have a picture?

Later, at work now.

Sir 51D3WAYS 08-09-2022 07:32 AM

Almost forgot bout this thread....

https://cimg7.ibsrv.net/gimg/www.rct...7e42b2e1b4.jpg
https://cimg8.ibsrv.net/gimg/www.rct...bc1b3e33cf.jpg


https://cimg9.ibsrv.net/gimg/www.rct...5ae9fad9d6.jpg
https://cimg0.ibsrv.net/gimg/www.rct...74eba7043d.jpg

gigaplex 08-09-2022 08:06 AM

That was after 2 runs? All the stickers look pretty tattered.

Sir 51D3WAYS 08-09-2022 06:03 PM

The last 2 pics are a very old ESC that has been beat to death, but still functioning.

The first 2 pics are a brand new esc.

ryandurepo 08-15-2022 06:23 PM

What do you have your esc punch settings at. Anything between 7-9 need a very high discharge battery otherwise you temp damage. I see you mention you run 90c but not a reputable brand so its possible that cause the damage IF you run a high punch.

Sir 51D3WAYS 08-15-2022 07:41 PM

I almost always run ESC punch at the lowest possible settings. I dislike punchy cars.

The batteries should be good imo, i know guys running them on 6s and 8s Arrmas and Xmaxxs etc, without issue.

The battery wires are kinda long as standard tho.....easily 6 inches. Hardwired packs, not bullets.

Smaller pinion?


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