Just had my first LiPo fire...

[Gruntfuggly 570]

My own fault - I was charging without the balancer connected, although I would still have expected the charger to cut off (it was in LiPo mode).

I was in the other room but my wife heard some hissing - the pack was swelling (hard case!) so I kicked it out of the back door. 30 seconds later it burst into flames - 4 foot high!

My wife is not impressed - "I don't want those things in my house any more!"

Two lessons:

1. Use the balancer.

2. CHARGE IN THE FIREPROOF SACK! (which I stupidly wasn't doing).

Note: This isn't a LiPo "scare" posting - I'm going to replace the pack. The point is that it was my own fault for cutting corners. The pack had also had a fairly rough life - big jumps in my Stadium Thunder...

[Jeepy2013 746]

Sorry to hear about your bad experience with your Lipo. I've been running Lipos since '08, luckily I haven't had any burst yet. (knock on wood)

[WillyChang 1816]

Glad to hear no humans or toys were harmed, bud. What brand/model pack was it?

Strangely was yakking with LHS just this week about puffy packs & what he did with them.

He beckoned me out back... his stripshop has a rear courtyard with a paved concrete area.

Out on the concrete was neatly laid out about 40-50 lipos each about 6" apart from another.

Most had burst their hard cases and were spilling out, but none had flamed.

He did mention there was a recent batch of Reedy cells that were made bad,

all the packs puffed within their first charge or 3.

[super gripper 419]

It goes without saying to only ever balance charge lipo's

I have seen quite a lot of lipo's swell and go puff but very little fire.

Again - Always balance charge in a lipo sack.

Oh well at least no harm came from it and all is ok.

I did read a very interesting article the other day about lipo's and people being scared of using them or what ever with the hype with regards to them.

it said ........ '' lipo's are not dangerous, its the idiots who don't know how to use them that are''

I thought it was funny and so true ..............

[Gruntfuggly 570]

@WillyChang - it was a Turnigy 4000 2S30C hardcase pack. I'm going to get a similar replacement as the size was perfect and it was great value (from Hobbyking).

@super gripper - That's very true - the only reason I had a problem was my own stupidity.

The reason I wasn't using the balancer was that when I started charging both my packs the charger stopped with an Open Circuit error after a few minutes. It seemed odd that it would happen to both packs at the same time (both have been working fine), so I though it might be the balancer (which is separate). So I charged one pack without the balancer - with the intention of balancing it at the end of the charge. It seemed to be charging fine (which backed up my theory about the balancer), so I left it going...

The fire was very impressive - I'm glad I wasn't holding on to it when it went off... I'd have been in casualty instead of posting about it

[WillyChang 1816]

yeah am noticing my Turnigy packs from 12-18mths ago are getting a tad chubby,

most have barely had 10 cycles on the used ones

got some Nanotech packs about a yr ago, used some & others unused still in their boxes

and they all look a bit fatter than before too... they're just stored indoors,

didn't bother putting them in the fridge over recent hot summer

haven't used the 4000s much as last xmas I bought some 2200 Nanotechs made for mini Traxxas,

they're so handy to stuff into any battery cavity in any car, the 4000s haven't been missed

[taliesin 260]

I too have a couple of packs that are starting to look puffy, but they charge ok and the numbers look good on the display (e.g. they aren't way out of balance). Are they still safe to store/use or are they automatically suspect when they start to puff?

I store them in a sealed ammo can and charge them in a Lipo fire sack, so I'm not terribly worried, but ... you know. Don't want to be stupid about it either.

I notice that all of the hard packs swell when used - just enough to show an opening in the seam of the hard case and then go back to normal after 20 minutes or so. At first I thought I was doing something wrong, but they always go back and seal shut and I don't notice any problem afterwards. I'm not over discharging according to the shut offs and the numbers when I recharge, but it is weird.

Lipos still make me a tad nervous - all the things I don't know.

[super gripper 419]

A slight swelling is fine but if your lipo's have already started to puff you have a ticking time bomb, get rid of them now

[biggamehunter 127]

scary stuff guys ??!

[shenlonco 1173]

Sorry to hear this.

Lipo chargers the balance plug is there brain without it connected there is no way for them to get a read out of the lipos status... this is why you MUST always have it connected to the pack at all times when charging.

[shenlonco 1173]

usually packs swell from

A over discharging

b using to low of a C rating for current the RC is drawing from the pack.

d getting over 140 degrees degrades lipos

I too have a couple of packs that are starting to look puffy, but they charge ok and the numbers look good on the display (e.g. they aren't way out of balance). Are they still safe to store/use or are they automatically suspect when they start to puff?

I store them in a sealed ammo can and charge them in a Lipo fire sack, so I'm not terribly worried, but ... you know. Don't want to be stupid about it either.

I notice that all of the hard packs swell when used - just enough to show an opening in the seam of the hard case and then go back to normal after 20 minutes or so. At first I thought I was doing something wrong, but they always go back and seal shut and I don't notice any problem afterwards. I'm not over discharging according to the shut offs and the numbers when I recharge, but it is weird.

Lipos still make me a tad nervous - all the things I don't know.

[WillyChang 1816]

usually packs swell from

A over discharging*

b using to low of a C rating for current the RC is drawing from the pack.**

d getting over 140 degrees degrades lipos

E charging beyond 4.20V/cell***

* discharge is fine... just don't recharge again!

** C rating is based on mfr's measurement of cell Internal Resistance.

Trouble is, I'm suspecting the IR goes down with age like nickel cells

as old cells feel less punchy & voltage dips more under load.

So their original C might not stand if IR has dropped.

*** me also suspecting the 4.20V always quoted is not necessarily safe

when the ambient temperatures are high.

From LHS fella who's been to visit a few lipo factories around Asia, he says

puffing is due to water moisture being boiled off from the electrolyte slurry.

Electrolyte needs to be poured into the foil sacks with some water in solution,

they are dried in an oven for 72hrs then the tinfoil sack is sealed with no venting possible.

If the desiccating oven isn't working right or the cells aren't in there long enough

to remove enough moisture then it'll swell even faster.

Some ppl freeze their lipos or store them in a fridge, I don't think it helps much

except for not getting too hot when ambient room temps go beyond 40degC.

Lipo fire also doesn't need air/oxygen, can't be extinguished until reactants are exhausted.

More important to get it away from anyone else that's flammable.

Which is why I'm a bit hesitant about putting multiple packs in a big tincan or Kevlar pouch,

won't the burning pack just heat up its neighbours until they too overheat & pop?

[shenlonco 1173]

With good chargers you can set the voltage you want to charge each sell up to and some have a 95% charge option so you don't charge exactly to 4.2V per cell... and some have a competition mode that lets you even charge higher than 4.2V per cell that's for the pure serious racers.

[WillyChang 1816]

With good chargers you can set the voltage you want to charge each sell up to and some have a 95% charge option so you don't charge exactly to 4.2V per cell... and some have a competition mode that lets you even charge higher than 4.2V per cell that's for the pure serious racers.

which chargers are those that you know of?

I've been looking for something that will balance charge to a user-settable #, I'd go for 4.05V/cell.

There's lots of fancy new chargers from Hitec, Sanwa etc but I haven't had translated their jap spec lists.

[B.M.T. 127]

Something Shelonco mentioned that never really comes up is the charger...

On a flying week end I am charging then storage mode conditioning up to 7 packs, and have 3 decent (name branded, not cloned or of dubious heritage) chargers working over time. After balance charging, I always stick each pack on my lipo checker to make sure the pack is reflecting what the charger display is telling me, and to this point things have been acceptable... i.e., correct.

UNTIL....

For obvious reasons I have wanted a quad charger but the $250 ish tag and then a 30 amp power tank to supply it has made running a bunch of separate units the go... Until I came across a quad for under $100. I thought "Well, all 4 button chargers probably are made in the same place..." Wrong. This thing, even when balancing was running the stronger cells up to 4.25 volts without addressing the dopier puff bags *. That is the point I terminated the charge, checked the actual cell statuses and then put them on discharge (storage) for a bit and went back to my old chagers.

I fly my planes on non "chinese" packs, as a randomly dead cell is bad news when you're up there, and luckily neither of the two packs that I had chosen to be the sacrificial worms were damaged, they took the abuse. What is concerning is that if that unit was bought by someone more trusting and not had the cell display screen up, and had not been hovering over it, because, it is a new thing, it should work, right? ... might not of had just a miff about a dodgy bit of hardware only to be worried about.

*"puff bags" - I dispose of soggy lipos. Just a term of endearment

[shenlonco 1173]

Hi my charger I use has 95% charge mode It's the thunderpower TP610C-ACDC I like this charger a lot.

http://www.thunderpowerrc.com/Products/Chargers_2

there better chargers probably have more adjustments

also the cellpro chargers are top notch also

http://www.revolectrix.com/cat.chargers.htm

[dyahipfakta 50]

This thread inspired me to check my lipos and I found one that was puffy in storage. So have binned it. Dropped it in the bin and heard a little fizz so cArefully fished it back out and put it in the incinerator just incase.

[Tamiya1/10 382]

Lipos are like women...you treat her well, you'll have hour of "fun", you miss treat her, even not knowly, she'll blow up on you....some still blows up on you regardless. Lipos can't do without them and can't do with them.

If one has a fire place at home,charge your lipo there. no need to buy a fire proof container and spend more money.

[shenlonco 1173]

Here is one of my chargers and it is very good quality I HIGHLY recommend i to anyone!

VIDEO SHOWING CHARGE MODES FOR LIPO MINUS COMPETITION MODE

http://s921.photobucket.com/user/shenlonco/media/MVI_0789_zps55b607be.mp4.html

[biggamehunter 127]

i use a balance cherger that is made by dynamite , the only lead is the power lead to the charger from the mains , you plug the balance lead only in it to charge , and when the battery is full there is a series of 3 lights that turn from red to green when fully charged , after charging i check on a seperate lipo alarm , it always shows charged cells as 4.2 and 8.4 for both , i store the batteries charged , is this correct ? please help , i have never had a pack swell , puff, smoke, or even get warm when charging , never ever had a seam open up , not even temporarily , on average i use the packs twice a month , then never discharge them , after use in the car , they are removed when the alarm sounds and just recharged in the same way ?? they are always charged in a fireproof bag but not stored in one ?? please help

[dyahipfakta 50]

Your better off storing the batteries at 50-60)% about 3.8 volts per cell. That is what I was told anyways then charge allow to cool and use

[94eg! 836]

i use a balance cherger that is made by dynamite , the only lead is the power lead to the charger from the mains , you plug the balance lead only in it to charge , and when the battery is full there is a series of 3 lights that turn from red to green when fully charged , after charging i check on a seperate lipo alarm , it always shows charged cells as 4.2 and 8.4 for both , i store the batteries charged , is this correct ? please help , i have never had a pack swell , puff, smoke, or even get warm when charging , never ever had a seam open up , not even temporarily , on average i use the packs twice a month , then never discharge them , after use in the car , they are removed when the alarm sounds and just recharged in the same way ?? they are always charged in a fireproof bag but not stored in one ?? please help

^That charger charges through the balance port? That is fine if the rate of charge (amps) is very low. How many amps does this thing output, and how long does it take to charge?

[shenlonco 1173]

Hi yes you want to store batteries at 50% charge 3.8V per cell 7.6V for a 2s lipo is fine.

Also that charger you have there is really not good for the big RC car batteries it will take for ever to charge them as you can not charge at a high enough amp rate through a balance tap... but if you want to wait for a very very long time you can still use it to charge your packs.

[biggamehunter 127]

thanks greatly for the info guys , i only use the lipos about two or three times a month and dont mind waiting a yonk for them to charge , as long as its safe !! the batteries in question are only turnigy 4200,2s shorty packs and dynamite 2200 , 2s ??

[WillyChang 1816]

I have 2 Nanotech 4200/2s shorties on the shelf @ 8.0V... 1 been used a few cycles, the other less...

Both getting a bit chubby after 15mths

It doesn't matter chargerate IMHO, I once put a lipo on 50mA overnight and it still puffed

Lipo chargers usually timeout after about an hour so if you go a lot under 1C, they might not get fully done.

I've tried Storage function on all the units I've used, afaik none do proper balancing...?

They just charge (or discharge) usually to about 7.4V and that's it.