My RX200S elected to spontaneously combust

[pipeman01]

First a bit of background. I've been racing electric (battery) powered radio controlled cars for over 30 years, and in that time I've developed a very strong battery safety ethic so I never leave batteries charging unattended, always monitor voltages and dispose of worn out batteries safely. During all my years of racing I only ever connected batteries up the wrong way once and it let all the magic smoke out of my £140 speed controller so I'm also very careful on battery orientation (in my cars now the connection lengths have been reduced so that the cannot be connected the wrong way as the - wire cannot reach the + connection).

Onto the RX200S... I bought this some months ago and to be honest it's not my favourite mod as it's a bit bulky for my liking but it's the only mod I have that can power my Clieto 120 as all my other mods max at 75w.
So it's used rarely and I have a triplet set of batteries I use only for this device.

All my devices are powered off at night (I have 5 mods all "active" with different atty's and juice most of time) but the RX was just on my desk, powered off without an atty.

About 20 mins ago it elected to spontaneously combust... acrid brown smoke came out of the vent holes and the mod got hot. I pulled the batteries out and opened the windows to clear the smell.

I'm currently running the batteries through a diagnostic test (in a lipo sack) on my racing charger and they are all coming up at 3.99v (4.0v is a sully charged cell) with no errors, so I suspect the fault lies within the mod and I'll strip it down later and see if I can work out what happened. I suspect it's a failure in the PCB which has somehow created a short.

I've always considered the stories around ecigs catching fire as user stupidity, now I'm not so sure and will be removing the batteries from devices overnight from now on. This wasn't user error, the mod has been sitting on my desk, switched off and unused for a couple of days.

I'd strongly recommend that you do the same... I'm not an electrical engineer but I'm used to working with LiPo batteries and the mods can self combust... I've just experienced it.

[VapingBad]

Good job you were present, well that was a deliberate act on your part not to take unnecessary risks.

[thebishman]

Blimey mate im glad thats all that happened!

On a side note... be great to see a thread of pics of your rc cars!

[jtc]

Not good to hear this.
I'm wondering how old the batteries are and how do they usually get charged?

[pipeman01]

jtc, the batteries are around 120 cycles / 1 year old and are usually charged in a modified old ProTrak charger all 3 at a time with 0.5A balanced charge.

The only thing I don't do is do a deep discharge to 3.01v prior to charging (which I do for my race packs, then charge them at 14A)

[jtc]

It is a worry, especially as you obviously know what you are doing.
So glad nobody was hurt mate

[enjay]

I don't suppose juice has gotten in? I've had mods auto fire in the past but it was due to leakage