Yet another Lipo Fire

lcyclist

10 W
Joined
Feb 3, 2009
Messages
96
While at out of the house today, my neighbor called me regarding a thick smoke coming from the front of my house. As I raced home,
3 fire trucks, a police car and the fire chief were in the front of my house. A good neighbor passing by had noticed the thick black smoke and called the fire department.

The fire came from my lipo powered scooter. I had just ridden it this morning, charged it and put in front of my house. The batteries were old and already puffed.
I have been meaning to replace it but had been lazy.

I was very lucky. The steel battery box contained the fire and protected my house. Exhaust vents and wire holes of the steel box prevented an explosion scenario.

No more lipo near the house for me. Be careful guys.

Here are some pictures of the carnage.

View attachment 1
topview.JPG
 
Any smoke damage to your home?
 
Looks like perhaps mechanical damage was a possibility, but maybe whatever you had in there with them just burned away.

What exactly was underneath the packs like? I've gotten a lot of scuffing on the bottom of packs, unless they fit very very tightly in the enclosure. Looks like you had them at least taped up some for more abrasion resistance.
 
wb9k said:
Any smoke damage to your home?


I was fortunate it was at least 8 ft away from the walls. I did not see any smoke damage other than some soot on the walkway tiles. It cleaned up with no visible damage with water
and a little green scouring pad.
 
dogman said:
Looks like perhaps mechanical damage was a possibility, but maybe whatever you had in there with them just burned away.

What exactly was underneath the packs like? I've gotten a lot of scuffing on the bottom of packs, unless they fit very very tightly in the enclosure. Looks like you had them at least taped up some for more abrasion resistance.

Yes, Dogman. I had it taped up and the bottom/top of the steel enclosure has a rubber lining, but sides are bare steel. It was not a tight fit. Earlier that day, I had ridden it quite roughly and may have had the cells rub, causing a short to occur.

There will be no more lipo around the house for me. I am building a steel enclosure away from the house to store and charge them.
 
one of the main conductors has the appearance of having shorted and overheated. can you see that?

rather than just make a bigger steel box, you need to simplify the wiring to reduce the risk of shorts and then use a BMS to turn off the battery when it does short out.
 
OP mentioned puffing, eh? IME puffing can distort pouches enough to short tabs. I'm not saying that's what happened here but perhaps worth asking your local Fire Dept investigator for their expert opinion? They can tell a lot about how a fire started based on the visual condition of wires and/or metal contacts near source of ignition.

Glad you're alright and suffered only minimal property damage. Good luck....
 
I am not asking these questions to draw any conclusion just build knowledge database type thing...
What was the size of the battery pack? What brand lipo did you use? And what charger do you use?
Cheers!
 
do you have the log of temperature and voltage of the sigle cells ?

I helps a lot to see what went wrong , sometimes it can be an internal short of the cell , sometime a localized overheating ..many thing can start a Lipo fire

Lipo are not 100% sure , are great batteries for power density and eneregy density , but greater power require greater responsability , the evil daemon of Lipo can emerge any time and only a loyal watchdog can save your house.
 
cwah said:
lcyclist said:
cwah said:
Did you use a bms?

No bms.

Another member had his house burned down because of this

Not just one.

Fire some time after charging is not uncommon. Someone lost there garage earlier in the year this way.

There is no bms used in any of the fire threads I have seen.

It does not really look like there have been any flames. I wonder if you got a full burn or not. That could mean the remains are unstable.
Sorry to see your toy in such a mess.

I found a post listing the 5 likely causes of lipo fire, and an explanation of each on another forum: http://www.rctech.net/forum/electric-road/182219-understanding-lipo-fires-101-a.html
A bms should sort out 3 of them. Hard case batteries a 4th. Leaving internal shorts out of our control. Nice metal box :)
 
There have been plenty of fires with BMS protected battery packs!

Of course all lipo fires wont have BMS as nobody builds packs from lipo cells with BMS they are all hobby lipo's

Lastly Please do not brand all lipos with the same brush Cheap Chineese lipo packs are a Time bomb and need to be treated with care they are not designed to fail safe and have very poor quality control.

The wiring in there looks dreadful with cables going everywhere bouncing around in a metal box without any padding.

The problem with Hobby lipo is they are so powerful that if there is a wiring short you will certainly have a fire.

Putting a fuse inline on each pack would mitigate this problem from bad wiring.

Silicon wire is extremely flexible but has terrible cut resistance (Can easily strip with fingernail) and thus precautions need to be taken via different wire or thoughtful wire routing or both.
 
My opinion, this fire likely resulted from some form of physical damage, packs able to rattle around in there.

Or, did the padding or whatever just burn away?

Could have been a short in the wiring, or pouch damage.

I've seen two main culprits in the RC lipo "time bomb" fires. Shorted wiring, like a mistake when assembling. And physical damage to the packs.
 
chilledoutuk said:
There have been plenty of fires with BMS protected battery packs!
I imagine so, but as a ratio of posts I have seen, the counter is still on zero. I have asked at least half a dozen times, but nobody has shown me a thread yet

Of course all lipo fires wont have BMS as nobody builds packs from lipo cells with BMS they are all hobby lipo's
This is not true. I'm sat looking at hobby lipo with a bms. Just because you buy from the cheapest outlet does not mean your cutting corners. Hobby packs always come with the correct bms wires hanging out of them, there is no reason to skip the safety device.

Lastly Please do not brand all lipos with the same brush Cheap Chineese lipo packs are a Time bomb and need to be treated with care they are not designed to fail safe and have very poor quality control.
What lipo pack is not chinese and fails safe?

The wiring in there looks dreadful with cables going everywhere bouncing around in a metal box without any padding.

The problem with Hobby lipo is they are so powerful that if there is a wiring short you will certainly have a fire.
For you maybe, you don't use a bms. I had a short and no fire

Putting a fuse inline on each pack would mitigate this problem from bad wiring.
Yes, with powerful batteries you need some sort of protection. On each pack would be great, but the balance wires are a problem. No need to call there delivery potential a problem though, It is certainly a bonus

Silicon wire is extremely flexible but has terrible cut resistance (Can easily strip with fingernail) and thus precautions need to be taken via different wire or thoughtful wire routing or both.
Sleeving is the proper solution. Insulation is not mechanical protection
 
Do not forget all pouch cells need proper compression for good performance. Few members had A123 pouch cells without compression and they failed.

Proper compression to prevent cell to expand or any mechanical shocks, as well as a good BMS and you have a correct lipo pack.
 
dogman said:
My opinion, this fire likely resulted from some form of physical damage, packs able to rattle around in there.

Or, did the padding or whatever just burn away?

Could have been a short in the wiring, or pouch damage.

I've seen two main culprits in the RC lipo "time bomb" fires. Shorted wiring, like a mistake when assembling. And physical damage to the packs.

i could see that his main conductor had been shorted but he never replied. if he actually did some kind of analysis where he looked at the shorted wire and tracked down where it shorted then we would learn something.
 
A BMS will only protect Some problems they will not protect from bad wiring and rats nests on the cell side of the pack.

18650 cells made by the big 5 can handle being shorted without exploding look at this data sheet for example.

http://www.batteryonestop.com/baotongusa/products/datasheets/li-ion/Samsung-SDI-ICR18650-26A.pdf

9. Safety
9.1 Overcharge Test
Test method: To charge the standard charged cell with 12V and 2.6A at 25℃
for 2.5 hours.
Criteria: No fire, and no explosion.

9.2 External Short-circuit Test
Test method: To short-circuit the standard charged cell by connecting positive and
negative terminal by less than 50mΩ wire for 3hours.
Criteria: No fire, and no explosion.

9.3 Reverse Charge Test
Test method: To charge the standard charged cell with charge current 2.6A
By –12V for 2.5 hours.
Criteria: No fire, and no explosion.
4
 
There very tame cells though. By 2c there down to 80% capacity. Max 4.25v so not really compliant with the average bms. Still, I'm surprised you found them.
It stands to reason that sluggish technology won't do a lot. I can't actually build my pack with them though, they are arguably different.

If you use these, and do short them, they could well burn up when they are charged again. Unless you have proper battery management they are little better. The fire could just happen another day.
 
A BMS may only reduce the risk

How do we know this is simply not from a short?
The other big garage fire, i am not convinced it was not bc-168's fault, that charger seems buggy as hell


however this issue, I am interested in how it actually started.
 
it was a short on his main conductor and you can see it in the photo. i hoped he would track down what it shorted to.

the reason a BMS would have prevented this is because when the conductor shorts the current surge will cut off the output mosfets and stop the flow of current.
 
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