Another LIPO FIRE ! Be careful !

[o00scorpion00o]

We can buy Dow Kokams ( $$$ ) that have slightly higher density than RC Lipo as of now. There is a group buy thread on it here.

BMSBattery offers some NMC battery packs, weak stuff though, 1C, prolly less in reality.
Batteryspace has some LiMnNi and NMC stuff for sale.
All-battery sells the tenergy v2 cells, but i am not 100% sure these are NMC.
Allcell is claimed to be li-mn, but i think it's NMC? Higher density than RC Lipo by a long shot, but only 2C max.

All close to, or exceeding the density of RC Lipo.
Most have low discharge ratings, however.

What we really need is something like the Dow Kokams, but cheaper.

Yeah the bmsbattery nmc seems to be a good choice for long cruises where you would set your current to 1-1.5 c max. But bmsbattery seem to lie about their size and weight ?

I must admit I've not heard of the allcell linm ?

I was partly following the dow kokam thread, but from what I gather they are not much more energy dense than lipo ? + they are harder to assemble for the average diy man, but they come in 16 or 20 ah cells greatly reducing wiring.

Anyone know the life cycle of nmc ? I would be interested because of the leaf when one becomes available at a decent 2nd hand price!

[boppinbob]

Sorry to here that. That is a sweet bike. Look how the shock is outside the triangle allowing more battery space. Sorry I'm off topic. Thanks for the post. I'm gonna check and balance charge at cell level today. I wonder if I should disconnect the 75amp connector from the battery to the controller every night? Dang we are getting bad news a lot lately.
Regards, Robert Pate
PS My ammo cans for storage should be coming in any day.

[NeilP]

I wonder if I should disconnect the 75amp connector from the battery to the controller every night? .

I do. just in case I either suddenly get called away/do not ride/..do not use the bike for what ever reason and suddenly it gets left a week..then a bit more..then it becomes one of theose jobs that you just must do..till it is too late and you forget..until you come to need the bike and then you get that horrible sinking feeling/realisation that the bats have been connected all that time, with a tiny 5mA drain, that maybe you were not aware of ..and that pack is toast

[dogman]

I disconnect every night. well,,,, except that day I came home with west nile virus and forgot. Three weeks later I realize my original v1 pingbattery is swollen twice it's size and ruined.

No fire though, lifepo4.

[kfong]

No matter how careful you are, things just happen. I had to take my lipo's out from storage last week to do some measurement and found them in my work room today. Just totally forgot about them and still have yet to put them away. It's easy to get lax about this stuff. My Konion pack was ruined last fall due to a bad weld. I had gone several cylcles on them since I was bulk charging. Without the balancing wires in place, RC chargers can't tell if something is wrong. If this had been lipo's I could of easily had a fire. The Konions took the overcharging without incident. I will only bulk charge with Konions or A123's. Never with lipo's. Ideally you want to balance charge even Konions or any chemistry just to know things are working well. This would of saved my packs, and I thought I had all bases covered. Can't complain, three years of trail riding in harsh conditions, and never battery or ebike problems except first starting out getting the kinks out of the system. The bad tab weld was a mechanical failure that I could not foresee and caught me off guard. So now I just assume a fire will happen and just plan for it. Especially since crashes on my bike happen quite often in the trails. I think metal battery enclosures or fire resistant composites enclosures are really necessary, especially for those who tend to leave the packs on the bike for long periods and continue to play with lipo. Just like wearing seat belts as mentioned earlier.

[Bazaki]

For myself I have a big main switch that cutt of all power, so no draining, also I have a big howling FAN at my 18 fet controller for cooling and I made it loud so I can here it, So the bike is alway really off.

Ofcourse the biggest risk of fire is while charging, and even the RC guys have had fire with balanced charging. But I also thought that lipo's that were just sitting there could'nt do any harm.

But there are a few stories at this forum that even when doing nothing the lipo got in fire, the hardcase sitting on the shelf situation for example, (almost fire ) and 2 other stories that did go into a real fire.
http://www.endless-sphere.com/forums/vi ... 14&t=29256
http://www.endless-sphere.com/forums/vi ... 14&t=36895 and here half the page.

So, the only solution is to remove the pack after each ride, but that is not gonna work for me. But it is scary to know that even when the lipo is sitting there it can go into flames

[Ypedal]

I bulk charge my 100v pack on my daily driver and will continue to do so, however i use the pack daily, watch pack voltage and capacity during use and will notice anything not normal, i pop a battery medic on the 4 packs ( 10 seconds ) before i hook up the meanwells, and charge thru a CA to monitor energy capacity going back in on every single charge ( in bulk) ..

After sitting all winter, cycled once last week, i will individually charge/ballance each pack using the RC charger and ballance leads , then start the riding season , 3rd year on this pack.

what happend here is pure negligence.. nicad could have made almost as big a bang under similar circumstances.

[neptronix]

scorpion, i can't give up my lipos just yet either, but would like the protection against that 0.1% chance that a non-abused lipo could go off.

Yeah i would not want to put those Dow Kokam packs together, after experiencing some snap crackle pop already, i am very squeamish about soldering such large & powerful cells together. Nobody has really came up with a good DIY solution for interconnection. RC Lipo is really convenient ( other than having to weed out the duds on a balancing charger ) in that way.

[boppinbob]

Until some battery solution is invented that is as safe as LiFePo4 but packs the awesome punch in a compact and super convenient connection format the conundrum will continue. I use boring old LiFePo4 for my 1/2 mile daily commute (leary of parking on company property with potenial sticks of dynamite strapped to my bike). I use lipo for the adrenaline rush of going high speed with amazing acceleration. In the mean time I will use my knowledge I've learn here to lessen the risk of using lipo. I don't mind posts of lipo fires because it reminds me that lipo is not very forgiving of mistakes or ignorance. Ask me to give it up and I say "hell no, I love my lipo"
'

[o00scorpion00o]

scorpion, i can't give up my lipos just yet either, but would like the protection against that 0.1% chance that a non-abused lipo could go off.

Yeah i would not want to put those Dow Kokam packs together, after experiencing some snap crackle pop already, i am very squeamish about soldering such large & powerful cells together. Nobody has really came up with a good DIY solution for interconnection. RC Lipo is really convenient ( other than having to weed out the duds on a balancing charger ) in that way.

No I wouldn't want to solder them either!!!

The only advantage with the dow kokam as far as I can see is cycle life, but I would rather twice the range over cycle life any day. And I think we have seen a major slow down in battery development, cycle life and c rate seem to be improving, but capacity not so much if at all. I think it will be 10 years before we see 2-2.5 times the capacity of lipo!

However for e.v's like the leaf, I think faster charging is more important than greater range. 70 miles at 65 mph is fine if you can charge in 5 mins or less without effecting the life of the battery and cycle life.

No one has said what the expected cycle life of NMC is supposed to be ?

[o00scorpion00o]

Until some battery solution is invented that is as safe as LiFePo4 but packs the awesome punch in a compact and super convenient connection format the conundrum will continue. I use boring old LiFePo4 for my 1/2 mile daily commute (leary of parking on company property with potenial sticks of dynamite strapped to my bike). I use lipo for the adrenaline rush of going high speed with amazing acceleration. In the mean time I will use my knowledge I've learn here to lessen the risk of using lipo. I don't mind posts of lipo fires because it reminds me that lipo is not very forgiving of mistakes or ignorance. Ask me to give it up and I say "hell no, I love my lipo"
'

LiFeP04 has it's uses as a commuter bike or for people that like plug and play. It's bigger and heavier than lipo and has longer cycle life at 100% dod at 1C usually. Higher C rate packs are very expensive!

I was in the woods today and gave the lipo a hammering with 30% + grades and pulling regular bursts of 5 kw. The pie was amazing and the experience was completely thrilling. It's the first time I took it to the woods after modding the controller. I was worried about cables heating etc but the 5kw helps me accelerate so quick that it builds up speed quick enough to reduce current draw quickly. And the motor wasn't too hot.

Only thing is I used around 7.5ah and the cells were around 3.65-3.7 volts, but they took forever to balance over 2 hours, so I obviously gave them a hammering. But I knew to check cell voltages and balance charge. These are the things you just simply cant over look using lipo.

[gogo]

Lip-O fire:
http://consumerist.com/2012/02/faulty-battery-likely-to-blame-for-electric-cigarette-exploding-in-mans-mouth.html
I know this shouldn't make me laugh, but come on, who doesn't know that cigarettes are bad for you?

[999zip999]

All these batteries can catch fire. ?

[boppinbob]

The US ebike modders are up shiite creek if the government discovers the growing popularity of ebikes and decides that current regs and taxes aren't invasive enough and regulates the crap out of it... and you thought your lipos from china were taking a long time to get to your door step now. Hell in DC they are hashing out regulations on how many squares of toilet paper you should be using to wipe your ass.

[flathill]

^--- word.

I'm kinda verging on not recommending ( or even mentioning ) RC lipo anymore, but i can't just yet.
I've been trying to educate people how to use lipo safely for the last year.
Others have too.
We have FAQs.

But still, the mass majority of RC Lipo fires that have happened here have been 100% preventable.
Even us heavy RC Lipo users do make mistakes from time to time, but with the right equipment and the right knowledge, you can prevent a mistake from becoming a disaster.

Unfortunately most people do not want to invest in the right equipment. Like in this case, a voltmeter ( or say, turnigy watt meter ) hanging off the charger would have provided a warning.

We REALLY need some affordable NMC, at or above the density of RC li-co Lipo. Or hell, a steady, legit supply of konion, a123 20AH pouch, etc. Something that can tolerate the biggest of dumb-ass moves.

This crap makes me real frustrated. Maybe i care too much.

All the chemistry you listed can still be bricked
ZCP FDP and SDP are why tesla doesnt attemp to revive bricked packs
See

Rechargeable lithium battery for tolerating discharge to zero volts
 Hisashi Tsukamoto et al

[neptronix]

All batteries can be bricked except maybe ni-cad, yes.

[boppinbob]

I talk about the need for taking care when using lipo, but when it comes to action I fall short. For my Sunday morning ride I did a balance charge because I'm paranoid with all this talk of lipo fires. When I do a balance charge I take the battery box off the bike. I put the battery box back on the bike after charging to 4.1 per cell (variance across 20 cells .002v)looks good. So I take the bike down the steps and the battery box detaches at the 45 amp andersons and falls to the ground. I had forgotten to secure it to the bike. So much for taking care.

[Hugues]

same here,
been reading this thread last night,
i told myself i got to be careful and check cells level before and after charging,
just to wake up this morning and realized i left the pack connected to the charger over night !
not good,
well, the charger is on a 4h timer, so it stopped for sure,
but it drained the pack a little, nothing to be scared about but...

[Jason27]

Yeah you gotta be very careful with lipo. Its almost not worth using just to save a few bucks over other batteries.

[Hillhater]

Yeah you gotta be very careful with lipo. Its almost not worth using just to save a few bucks over other batteries.

Its not just $$$'s .. lipo saves you a lot of weight and space, and will give a lot more amps than most any other battery chemistry of similar Ahr capacity..

[neptronix]

Yup. not just money. Small, light, cheap, powerful, easy availability, easy assembly ( versus something like buying pouch cells )..

Don't act like you've never seen a battery spec sheet before

[jonescg]

Y'know, if A123 decided to make their amazing 20 Ah pouch cells in say, a 5 Ah format, roughly 50 mm by 140 mm and 9 mm thick, I would leap at them in a heartbeat. Wonder what it would take to get them to re-tool?

[Jason27]

Ya but look what it did to that bike.. yikes!

[boppinbob]

If A123 had at least 5c discharge rate it would be viable for a lot more lipo users. It's kinda of like the firecracker world. Black cats seem lame after setting off M80's.

[amigafan2003]

Ya but look what it did to that bike.. yikes!

Best not drive a petrol powered car either

Remember, risk management isn't about avoiding or eliminating risk but rather about ensuring the level of risk is understood and is proportional to the expected benefits.


For me personally all my EV bike stuff is stored in the garage that's detached from the house. It, along with the Westfield sportscar, high end mountain bike and ALOT of tools that also live in the garage are all adequately insured. A serious lipo fire would merely be an inconvenience so I wont lie awake at night worrying if it's going to go pop.