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LiPo Fire Pictures
Pictures from the fire, from the right - I have a tire left! Here's the story text
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Last edited by ken_keeler; Aug 09, 2003 at 03:56 PM.
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And the interior
So much for the Firecat and TA152.
:0 |
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For others who missed your original report like I did, here's a link to it.
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Latest blog entry: Taranis: Several Models, One Setup
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So what happened ? This was caused by a LiPo/Charger malfunction ?
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Ken,
There, but for the grace of God, go I! I had a Kokam 2S1P 1020 pack short while it was on the passenger seat of my BMW Z3. Luckily for me (?) the only damage was a large hole meted through the middle of the seat so that my insurance claim just amounts to having the seat replaced, not the entire car as in your case. Anyway, here's a picture of what remains of the Kokam pack. Cliff |
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Cliff, Ken,
Thanks for sharing your experiences: my conclusion is I must be more careful when handling these cells. I usually throw my packs in my field box or simply leave it on my planes... Cliff, Were you able to determine what caused the short: wiring/connectors outside the pack, wiring within the pack itself or an internal cell short (hopefully not this one...) ? Cheers, Danny |
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We have to remember, with the current ratings and internal resistance of these packs, they can deliver horendous amounts of current in the case of a short. I build/rebuild battery packs for motion picture cameras and also for insurance investigators who use hidden cameras. We are currently looking for an ideal material that we can put these battery packs in that would act like a fire retardant/suppressant. In the mean time, we are warning our customers about the care and feeding of these wonderful new batteries.....
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Danny,
When I put the batteries in the car that morning I even noticed a small split in the heatshrink over one of the 2mm gold connectors I had on the Kokam pack and thought "must fix that when I get home tonight". I never envisaged that I'd be so unlucky for the connectors to touch at just that point but clearly that's what happened as the connectors were partially fused at that point when I recovered the melted bits. I never thought that there'd be so much stored energy in just a small 2S1P pack of 10120 Kokams to cause this amount of damage. Like Jim says, they have very low internal resistance and can clearly dump huge current if shorted. I've certainly gained a lot more respect for Lithium since this happened. (Some years ago I had a 7 cell 1900 NiCd pack short and some of the cells vented and the heat shrink melted/split but the damage in that case was no where near as severe as this). Cliff |
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Thanks Cliff, that truly is bad luck...
When I built my first lipo pack (3 3270 cells) I worried about the tabs of the three cells sitting very close to each other so I decided to turn the middle cell 180 degrees: requires about 9" extra wiring but I felt safer doing it this way. I think these cells can handle a fair amount of mechanical abuse (have seen pictures of damaged cells around here...) but like you said we need to treat these little gems with more respect. Cheers, Danny |
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