Lipo Warning - Scary

[Eoin]

Gentlemen,
Just posting this as a reminder of the dangers of Lipos.
I sat down tonight to build a voltage regulated circuit to step down my 4s to 12 volts for my LED's.
I was using a breadboard to test the circuit. To set it up I initially used a zippy 2500mah 6.6v 2s with a nano tech 4s waiting in the background for the final test. The 2s was connected to the breadboard using a charger cable. It was a pre-made charger cable that came with my charger and appeared well made. When not working directly on the breadboard I disconnected one of the charger leads from the board.
What's frightening is that I'm still not sure what happened. I was engrossed measuring resistors with my multimeter and didn't notice the first plume of smoke until I heard the sizzle. I looked up to see the cable connecting the battery on fire and fast making it's way towards the battery. I grabed my snips and cut one of the battery leads to stop the short circuit then I immediately threw everything outside.
I'm still shaking ! The 2s battery was sitting directly on top of the 4s and I shudder to think what would have happened had they both caught fire. It was obviously a short circuit but I have no idea how it happened. I suspect one of my tools came into contact with it but for the life of me I can't figure out how. The fire started where the battery joined the cable. These are servo connectors so the battery cable was sitting snugly in the connector.
Anyway, just a reminder of the dangers ! I'm walking away from it for tonight. I'll finish the regulator tomorrow.
Eoin

 

[Vojec]

I can imagine. Similar thing happen to me a couple days a go. Try to parallel wire 2 lipo 4S battery and I don't know why or how wire serial ballancer together (Y) and parallel battery connectors, and ka buum smoke and fire, grab and threw outside as quick as possible.

Yes, no joke with Lipo.

 

[iceman]

Always use a lipo "safe" bag while charging, testing and measuring even while storing your lipo

 

[Eoin]

I hear you Iceman !
I had two safety bags in the room with me and didn't use them.
I won't make that mistake again.

 

[kloner]

even the best get caught by this and don't react right. while back Curtis Yougblood was flying at his shop like any other day and was charging inside when he heard the same thing you did. Freaked out, grabbed the battery and threw it outside. Wound up in the burn unit with either 2nd or 3rd degree burns on his hands. I kinda quit looking for news so no idea how that worked out.

The best way to keep them is outside/garage, over concrete in blocks or similar. that way if one goes, doesn't take the rest with it. the most important thing not to do is keep them in a sealed case, it'll make the case a bomb if they burn inside it.

 

[Macsgrafs]

The problem here wasnt the lipo. but the circuit you had it plugged into. As a former radio tech, one thing I was always told...check, then check again & then once more just to be sure (checking for shorts).

Ross

 

[kloner]

yea but nimh or nicd just get hot, wires melt, cells pop.

lipos start this polymer smoke bomb fire that is unmistakable. smoke turns into what looks like welding, then the next cell lights. I crashes a 12s heli in my driveway. broke a velcro strap and slung a 6s 5000 into the path of the blade and slid off into a field. It was freaky, didn't know what to do other than keep it out of the brush. Your left with a stack of plates that look like a notepad and wires everywhere

 

[Eoin]

Your right Macsgrafs.
I thought I was actually being careful but obviously not careful enough ! My biggest mistake was to not use my safety bag.
I investigated the cable earlier today. As far as I can make out the short happened when two pins touched inside the connector that joined the battery to the charger cable. I suspect it was damaged but I didn't spot it.
I have just finished the circuit. All testing was done with my lipo firmly sealed inside the bag !

 

[PapaRomeo]

View attachment 4244 10S 5000mAh Vario Acrobatic E converted.

 

[Eoin]

Actually, I've just been thinking more about this incident.
I have two safety bags similar to this one http://www.rcpal.com/lipo-battery-shield-safety-bag-p-151.html
But I have about 12 batteries. I'm seriously considering purchasing a bag per battery and making sure that every time I buy a battery I buy a bag. How good are these bags ? Is there a better option for transporting them ?
Also I keep a small fire extinguisher in my Jeep as a matter of course but I'm wondering if I should upgrade it. What's the best extinguisher for dealing with Lipo's ? I realise I can't stop a lipo mid fire, but I'd like to minimise the damage.
I think I need to get more serious in terms of lipo safety.

 

[kloner]

nothing puts it out, just puts out what they light. there like solid fuel rocket motors, burn till there outta fuel. Co2 is the cleanest

I've heard of alot of cinder blocks and metal cans as being alot of folks way of storing/transporting. i personaly just let em ride and never hang onto anything thats been damaged either internaly or physically. When i'm in the field playing with the stuff, it's so hot there in ziploc bags and a cooler unless there charging or flying. at home i keep them on a tile counter in those plastic storage containers, shoe box size, all touchin each other, but i know not taco'd

 

[Eoin]

Thanks Kloner,
I've just been looking at some YouTube videos of lipo fires and the bags do look as if they are quite effective. Not sure how long they would last with a 6s though. Need to do more research. I think I'll definitely upgrade the fire extinguisher in my jeep.

 

[Hedge]

Been flying a while now and the stories of fires are common enough not to be folk lore. I keep mine in an old army ammo case (get them off ebay) and in the ammo case they are stored in 2 lipo sacks, with each sack holding about 16 cells at 2200 mAh each and they are stored on a concrete floor.