3s Capacitor Fire

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KevWannaBe

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Hi all,

RC newbie here and my first post. I bought an essentially written off 3s senton. Replaced all the bearings and even the bearings in the brushless motor. All is well, probably 10 packs through it so far. Today I went to the park with the kids. Ran through 1 pack and played football. I turned the car off but DIDNT unplug the battery. After 45 minutes or so. White smoke pouring out of the arches!!! Ran over, whipped the shell off. The capacitors on the ESC are on fire, literally burning!!! The ones on the battery cable. Unplugged and put out flames. I have questions:

1. Why would the capacitors go up when the car is stationary?
2. The battery seems okay, will it be? It looks fine.
3. Can I replace the Arrma 3s Capacitors and be up and running again? Or is the ESC cooked?

Just showed me these things need treating with respect. If it had of been at home and we were not around to put it out????????
 
There was a dead short somewhere. As simple as that. Was it wet? Did it take any impacts?
 
I was blasting it around and the grass was very wet. No big impacts...
My guess is the ESC was no longer water proof and you got a dead short from moisture inside.
 
Hi all,

RC newbie here and my first post. I bought an essentially written off 3s senton. Replaced all the bearings and even the bearings in the brushless motor. All is well, probably 10 packs through it so far. Today I went to the park with the kids. Ran through 1 pack and played football. I turned the car off but DIDNT unplug the battery. After 45 minutes or so. White smoke pouring out of the arches!!! Ran over, whipped the shell off. The capacitors on the ESC are on fire, literally burning!!! The ones on the battery cable. Unplugged and put out flames. I have questions:

1. Why would the capacitors go up when the car is stationary?
2. The battery seems okay, will it be? It looks fine.
3. Can I replace the Arrma 3s Capacitors and be up and running again? Or is the ESC cooked?

Just showed me these things need treating with respect. If it had of been at home and we were not around to put it out????????

You don't need those capacitors, ESC candy.. Cut them off and plug in a battery to see if the ESC is cooked.. Stay safe and be ready to unplug it quickly just in case.

If you were home, chances are you would have unplugged the batt from the truck so a house fire would be next to 0.
 
NEVER RUN AN RC IN WET CONDITIONS!! Even if the manufacturer says it’s waterproof, water can still damage it in some way. I never run my RCs in wet conditions because of the damages water can do.
 
NEVER RUN AN RC IN WET CONDITIONS!! Even if the manufacturer says it’s waterproof, water can still damage it in some way. I never run my RCs in wet conditions because of the damages water can do.
I bash all winter and have never had a issue.

This was a fluke. Not a common occurrence.
 
NEVER RUN AN RC IN WET CONDITIONS!! Even if the manufacturer says it’s waterproof, water can still damage it in some way. I never run my RCs in wet conditions because of the damages water can do.

Dude. I run my RCs in any weather, and my crawlers literally go underwater.
 
Dude. I run my RCs in any weather, and my crawlers literally go underwater.
Crawlers don't use exposed Cap packs. I run my crawlers in the wet also. Just that OP had an exposed Firma Cap pack in this case. Water was most def the problem??
 
I agree with the exposed cap pack and water thing. Wet grass is too fun to pass up at times. Waterproof expanding foam into the opening of the cap pack openings, or inject silicone. will help a lot but the only guarantee in the world is nothing is guaranteed.:)
 
@KevWannaBe,
2 problems here.
I probable causation.
And one definite causation.
No RC electrics are WP despite what is documented. From experience. That Firma 3s Cap pack has always been a problem, nonetheless. IMHO. It is not even secured well enough. Usually a dead short occurs somewhere as @jondilly1974 stated above. And most likley at the cap pack wires, in your case.

And IF you disconnected the Lipo after running, a fundamental rule, not just switching Power Off, the Cap Pack would not have been energized to begin with. It would have been isolated from the Lipo circuit. A failsafe to always do this! Would have prevented the fire.
Imagine driving home with that rig in your car while it torched up??? Tragedy for sure.:(
Not disconnecting the lipo was the definite cause of the fire.
User error.
 
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Burning Burn Baby Burn GIF by Jimmy Arca


Not taking away from the seriousness of the correct ways to handle Lipo batteries but it wouldnt be me to not throw in some humor.;)
As @SrC has stated unplugging the battery is the 1st and important step after a run.:)
 
Can the cap pack be replaced or can I just 'cut them off' as advised above?

Damp grass is a No-No?????? Hardly ARRMA Tough?
 
Can the cap pack be replaced or can I just 'cut them off' as advised above?

Damp grass is a No-No?????? Hardly ARRMA Tough?
Damp grass should not be a problem, but it can be if you have a defective used rig. Out of the box it should be fine. But who knows how it was treated before you got a hold of it. And there was likely no way you could have known either, so I’m not blaming you at all. Just the way things go some times.
 
Hi all,

written off 3s senton.

I’m assuming you have a BLX100 - if not, the rest may not apply

The capacitors on the ESC are on fire, literally burning!!! The ones on the battery cable. Unplugged and put out flames. I have questions:

Are you referring to the capacitors that the blue arrow is pointing to or the ones the red arrow is pointing to? You make reference to caps on the ESC (red) while some posts are making reference to the attached cap pack (blue). The attached cap pack would be easier to replace if the caps there were damaged (and the rest of the ESC was fine) but the caps on the ESC would not be quite as easy to replace - or nearly impossible if the PCB is potted.

5F0FB7A9-DAB2-4A58-B1DA-91D7929ED43E.jpeg
 
I’m assuming you have a BLX100 - if not, the rest may not apply



Are you referring to the capacitors that the blue arrow is pointing to or the ones the red arrow is pointing to? You make reference to caps on the ESC (red) while some posts are making reference to the attached cap pack (blue). The attached cap pack would be easier to replace if the caps there were damaged (and the rest of the ESC was fine) but the caps on the ESC would not be quite as easy to replace - or nearly impossible if the PCB is potted.

View attachment 182737
Pretty sure the BLX100 is potted.
 
I’m assuming you have a BLX100 - if not, the rest may not apply



Are you referring to the capacitors that the blue arrow is pointing to or the ones the red arrow is pointing to? You make reference to caps on the ESC (red) while some posts are making reference to the attached cap pack (blue). The attached cap pack would be easier to replace if the caps there were damaged (and the rest of the ESC was fine) but the caps on the ESC would not be quite as easy to replace - or nearly impossible if the PCB is potted.

View attachment 182737
Thankyou.

I am referring to the blue arrow Capacitors on the wire. It's a BLX100. The wires running into the capacitors are charred but there is enough length left for me to solder new capacitors. Can they be bought separately?

The car itself was used and abused before with many bearings seized when it came into my possession. The bearings had gone in the motor and I did a full rebuild. More than likely the capacitors had some damage.....
 
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