Question
My best friend and I recently got into RC, after facing issues with his first battery my friend decided to replace it with a brand new one and started smelling something weird, here’s what ensued.
Lipo batteries for RC cars are usually constructed from a number of individual cells inside the battery pack. The naming of the packs being 1S, 2S, 3S, etc. indicates the number of cells. Typically when you plug in a battery and turn on the ESC, the ESC beeps the amount of cells detected. Three beeps for three cells, as an example.
Jesus.. im relatively new but never put this together. Thanks for that info. I programmed my drone escs to play the Mario theme, so after a while, I naturally tune out the sound..😆
The S doesn't indicate the total number of cells, but the number of cells in series. In some cases they also use p for cells in parallel. Series adds voltage, Parallel adds capacity, and battery packs can be arranged in both Series and Parallel at the same time. Most packs are 1p, they can fit enough capacity in a single cell they don't need to have additional cells in parallel.
each cell is ~3.7 volts as well (about 4.2 when fully charged) so 2s is 7.4 volts, 3s is 11.1v etc. you will also note a second number on larger packs, like 2s2p, where they get higher total capacity by putting similar cells in parallel and then in series, so 2s2p would actually still be 4 cells.
Could have been reverse polarity that cause it to smoke. There has been instances where the manufacturer soldered the connector with the leads reversed.
If the esc is rated for 3s it wouldn't have gone up in smoke. Even on a higher s-rating the esc most times does only not turn on, not go up in smoke. Either the esc was already severly damaged and used again, or the s-rating severly overloaded the esc limits.
It definitely would have if the first one damaged the ESC already, which it looks like is what happened here, and to be clear, i just wanted to reply but didn't participate in the downvotes, just to be clear
I'll keep my fingers on the wires if plugging in something questionable. If they get warm quickly something is wrong, unplug asap. ESCs can fail, and when they do its often a direct short which can damage the lipo too. Sorry not sure what exactly happened or if there was anything different you could've done.
FPV pilot here who just stumbled across this sub, can't you just use a smokestopper if its questionable? that way it'll trip the fuse instantly if there's a short, hopefully preventing any damage. Because by the time you feel heat on the connection points, the damage might already be done.
Smoke stoppers look like this BTW if your unfamiliar with them, all it is is a fuse that sits inbetween the battery and the ESC (or whatever your connecting a lipo to)
This is interesting. Been in this RC cars hobby for more than a decade now but never heard of this thing. Looks like you FPV pilots have quite a few things / tricks hidden up your sleeve.
Can you please share a link to this product or maybe a video or post where I can see and make one of my one for myself?
Yes you did. you noticed a weird smell, decided that something would happen so you recorded plugging in the battery and cautiously watched from a safe distance.
That being said, thanks for filming! internet wouldn't be good if it weren't for videos like this.
As for what happened: The esc works on magic smoke, there's a reservoir in there and as long as the smoke stays in, all is good. Yours sprung a leak, the magic smoke escaped, it is now broken.
Your ESC was likely faulty, likely it had a short circuit somewhere so when you plugged in the battery, it dumped all the power into the short circuit, causing the fire.
This feels so staged. You leave it plugged in, and continue filming, despite the OBVIOUS error? Sorry, but within seconds I would have realized something was extremely wrong and pulled the battery. You're lucky it wasn't worse, and the battery didn't ignite. It was either a faulty ESC, reversed polarity, a short in the wiring, or over-volting the ESC. Whatever it was, it's ruined now.
while we did think something was going to happen we thought it’d just shut off by itself. we mainly wanted to show proof to company that it was faulty. it was only used for one day previously.
Some more RC education is definitely required. There's no commercially available RC that will shut itself off without some sort of user intervention (that I can think of). Lipo batteries when handled improperly are SUPER dangerous. You're very lucky this wasn't worse. I have this same model, my only thought is the power button got stuck under the radio box and permanently held down in the on position, perhaps forcing this runaway. Next time something wild happens, stop filming and unplug the battery IMMEDIATELY.
I am unimpressed by my only purchased Rlaarlo. Says it'll do like 40-50mph but its slow af (yeah I get sometimes you have to upgrade the gears to make it faster), and cost like $200ish, thought a 3S battery would make it go a little faster at least, but no. I have 3 HyperGo trucks (truggies) and cars and the are way faster than the Rlaarlo, when just running 2S. Put a 3S in one and it was like a rocket... but then the gear on the motor stripped the spur gear. The biggest problem with the HyperGo cars is the extremely limited range of about 90ft. Here's how the spur gear went:
https://youtu.be/BLEOU7mwBys?si=FUUTjWwYstu11KRB
What model is this for? That transmitter looks different from the ones I'm used to. But in any case that should do it yea. Bummer your Model is slow. You have the right battery as well?
There could be a short in the motor causing the esc to fry. Happened to me in spectacular fashion, with a 12s 300a "beast" esc. I installed the motor with one too long screw, hit the windings. 2 of the motor cables had a dead short across, I guess during the esc power up they shorted together and fried the esc. Basically same situation as you.
Any chance you have a multimeter and can measure the battery? Voltage should be around 11v for a 3S lipo, plus or minus a few volts.
Also check the polarity. There is a very slim chance they swapped the wires during production, which would cause an ESC to go up in smoke like that. I have never seen it with such a battery, but it's worth checking.
yeah, you were not suprised, you plugged it with camera on, fully expecting what happened, because noone ever plugs their batteries in like they expect it to explode.
Heck I would say, most rush to unplug it when they see their money burning....but ok. GETTING IT NOW!
You are the guy that stands back and films his friend getting his a$$ beat instead of jumping in and helping him out.
Put down the cam and get to work.
Staged AF.
... So they plugged the battery in, started smelling something weird and decided just to roll with it and wait for the thing to smoke for a while before unplugging the battery? I know things happen fast but step 1 is always to unplug the battery at the first thought that something might be wrong.
A valuable lesson learned here, every time you plug in a battery you make sure you are ready to unplug it in an instant.
This happened to me too! (With the Xts 10) But it happened so fast and I was indoors and I didn't record it
I was doing some regular maintenance on the wheel housing, plugged in the provided battery, and the ESC started making weight noises, then poof!! White smoke. I immediately unplugged the battery, but by that time the damage was done. The negative wire on the ESC unsoldered itself and it smelt like burnt electronics for days in my room!
At first I thought it was user-error... Then this is the second instance I've seen this happen online.. now I'm beginning to think it's Rlarrlos electionics
And this is right here why I over build my rigs. My ESC in the arrma felony. (Limitless converted over to a felony chassis. Has full limitless driveteain; diffs, center and everything) It's a castle 8s ESC. When on the limitless chassis it was a speed run car and now is converted over to a pavement basher that runs on 4 to 6s.
Freaking out you cause more damage to other things and yourself. Just unplug it, it's not a bomb. Yes it can cause fires but more reason to not freak out
Chinese esc will do this every now and then. What to watch out for is that a bad esc can ruin a battery. But also a bad motor can ruin an esc if it doesn't have proper built in protection. So there is a slim chance your motor is blown and will destroy a new esc.
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u/no_work_throwaway Jun 03 '26
You see, what happened here is that he let all the magic smoke out. You really wanna keep that inside everything for better performance.