Bike going up in smoke

Kokam Lipo, 36V 10Ah. Battery got sent to after sales service for a blown fet late december. Early January, after a speed bump the user felt a decrease in power, but kept using the bike. Called service, but there was nothing obvious, guy was asked to take pics, guy used the bike to go to work the next day, with his camera.

[googlevid]-1086364983225733633[/googlevid]

http://www.velectris.com/forum/s1705-batterie-part-fumee.html

No huffing the smoke!

Yikes!

Don't park that indoors.

I wonder if it lacked a fuse? At least it didn't burst into flames.

It's worth showing the image...



...makes one think that a true "crash and burn" could be possible if everyone used LiPo.

Nasty, all packs should be fused, lipo or otherwise, this looks like a dead short has happened somewhere. A fuse should prevent this sort of thing.

also if this turns into a lipo bashing tread, to keep this in perspective, be aware of the dangers of all batteries, Nimh and Nicad are particularly dangerous when they go wrong, they can explode like a grenade ejecting there casing like red hot razer sharp shrapnel.

http://www.rcuniverse.com/forum/m_6215238/anchors_6219190/mpage_1/key_/anchor/tm.htm#6219190

even LifeP04 can explode, this one could easy have burned the house down.

http://www.rcgroups.com/forums/showthread.php?t=709190

http://www.rcgroups.com/forums/showthread.php?t=772399

will any fuse do? or do you need something a little special like one with a microprocessor?

stew007 said:

Nimh and Nicad are particularly dangerous when they go wrong, they can explode like a grenade ejecting there casing like red hot razer sharp shrapnel.

Click to expand...

The guy in the link put his cells on a charger that trickle charged for 7 hours... no wonder it exploded.

You are only supposed to charge until the delta v signal... then completely terminate. Otherwise they can get overheated and do this sort of thing. This battery was probably smoking for three or four hours before it exploded. I always watch my charge and never charge more than the others started at the same time. (I charge six sets at a time) If five out of six are done then I just turn the last one off if it's warm. Most of the time mine are done in a little over an hour charging at about 0.75C.

NiCads are generally a more stable chemistry than most others.

A low rate trickle is perfectly ok with nimh/nicad.. ( used them for 2 years.. left trickle overnight plenty of times )

http://www.ebikes.ca/batteries.shtml

Conditioning and Balancing

NiMH and NiCad are both blessed with shuttle reactions that allow small amounts of current to continue to flow both during overcharge and over-discharge. Battery packs that have been sitting in storage for some time will often wind up with some cells more charged than others. This happens because the internal leakage currents are not necessarily the same from one cell to the next. When the pack is charged for the first time, some of the cells will be top up before others, and the shuttle reaction allows charge current to continue flowing through the pack untill all the cells are topped up, without damaging those cells that got overcharged.

NiMH packs that have been on the shelf for a year or more will usually not give near their full capacity on the first discharge. It takes several cycles before the battery will reach its optimum performance, a process known as conditioning. The graph below illustrates the situation with a NiMH laptop battery purchased at a surplus store. The first discharge yielded 1.1 Ahrs, then second 1.6, and by the fourth cycle the pack had stabilized at about 1.8 Ahrs. You don't need to do anything special to condition the pack, simply be aware that it might improve during the first few usages.

I'm not sure a fuse would've helped, if it was an internal short between cells. Even overdischarging can cause LiPos to spontaneously combust. Once the start cooking off, the heat is so intense that you pretty much have to let them burn out. I have never had any luck putting out a burning pack of LiPos, until they last cell has cooked.

-- Gary

I don't see what the problem is.

safe said:

Click to expand...

More proof. Front hubmotor bikes are just too dangerous.

dogman said:

More proof. Front hubmotor bikes are just too dangerous.

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Ha! Good one...

Mathurin said:

Kokam Lipo, 36V 10Ah. Battery got sent to after sales service for a blown fet late december. Early January, after a speed bump the user felt a decrease in power, but kept using the bike. Called service, but there was nothing obvious, guy was asked to take pics, guy used the bike to go to work the next day, with his camera.

[googlevid]-1086364983225733633[/googlevid]

http://www.velectris.com/forum/s1705-batterie-part-fumee.html

Click to expand...

wow i can picture what whould happen to mine lmao i got 2 100v 10 ah packs lol if thoes got hot id be running like a crazy man lmao i bet it whould cause a smoke screen like teer gas i bet lmao