Lipo's - Food for thought...

[Groomi]

http://www.liverc.com/news/special_f...ave_got_to_go/

I think it's right to question the continued use of lipo's in the face of unsettling failure rates, however it will always be true that the majority of racers will not want to be made to go slower.

Thoughts?

[richm]

its quite daily mail.

i am not doubting that lipos can be dangerous. and have been fortunate that in the short time ive been racing that i havent seen a fire, and ive been using lipo batteries for work for years with no issue (as well as LiFe for 18 months).

but what the article doesnt mention is how any of the fire may have started. was there faulty wiring involved in the car fire? was a battery left unattended on charge overnight? depending on how your connectors are setup, there may not be any protection if something shorts out the terminals whilst you are charging, or when the cells are in the car and connected to the speedo. how old were the cells? had they previously been mistreated or the case modified?

almost anything i search for on google will have hundreds of thousands of hits, but how many of them are individual rather than repeating the same info / source?

and i have seen a lot of poor soldering on both battery and motor terminals which can cause problems if wires some loose.

im not questioning the safety of lipos, just pointing out that the article could use a bit more research.

[beale]

Not sure how you post a poll on here but if we all put how many cells we owned in total with estimated total charges then compared it to actual failures most not even creating fires we would say 98% safe and probaly class nimh's as being more dangerous,
I've had a 3 year old pack puff enough to split the case by leaving it fully charged for 2 weeks (in a steel box) dumped it in a bucket of water for a few days tested 0vdc so took it to the tip battery box job done!

[stumpiey]

i suspect that most of the time it is user error, the amount of times i have been racing and some guy is laughing about how puffed his lipo is, and there is those that charge on the wrong setting etc etc, lipo's are not dangerous, people are, if lipos was a problem with bursting into flames randomly then we would have read about shops burning to the ground on a daily basis.

also, how many lipos are out there being used everyday without a problem, they are everywhere, not just RC, phones, ipods anything battery powered could have a lipo in.

this is like a daily mail knee jerk reaction trying to fan some lipo flames

[DCM]

Anything is dangerous if you become complacent about things, and this is what happens with LiPO's in the main. We could post the same thing about chip pans, hair dryers, cars, motorbikes, BEER even. At some point the end user HAS to take responsibility for their actions.

I am sure the author of the 'wheres waldo' articles has good intentions with the article but, just maybe, to get page hits up he/she has gone for shock tactics.

[catman79]

i personally think the banning / withdrawl of lipo batteries would be a massive, massive backwards step for the sport. ive been racing years, and during the last few years of nimh use, i was replacing the cells every 6-8 weeks, just to keep up with the top guys at our club. nowadays lipo's last a season. and with numbers dwindling as is it would be suicide to ban them, but as people have said above, it wont happen. its a lovely article by wheres waldo, but a complete waste of (virtual) ink.

[mattr]

"Unsettling failure rates"

FFS.
I've just returned to the hobby after a 25 year break, when i stopped driving, we'd see at least one or two cells pop every month, and that was just the club drivers. Any big competition you'd get that in a single day.

This time round (nearly 3 years at it) I know of two cells failing at our club and as far as I know both were being charged at higher rates.

The actually failure rate is incredibly low, I'd go so far as to say it's statistically insignificant. And a good number can be attributed to stupidity or misuse.
(Wasn't there a thread a few weeks ago about rapid charge/discharge/charge cycling to get the battery nice and warm before your event? That's stupidity, or misuse.)

On the other hand, the severity of a failure is higher.

[HOTSHOT III]

Originally Posted by stumpiey

i suspect that most of the time it is user error, the amount of times i have been racing and some guy is laughing about how puffed his lipo is, and there is those that charge on the wrong setting etc etc, lipo's are not dangerous, people are, if lipos was a problem with bursting into flames randomly then we would have read about shops burning to the ground on a daily basis.

also, how many lipos are out there being used everyday without a problem, they are everywhere, not just RC, phones, ipods anything battery powered could have a lipo in.

this is like a daily mail knee jerk reaction trying to fan some lipo flames

100% agree, at a club I used to race at there was a guy with a really expensive 1:1 scale car who used to charge LiPos in the engine bay without a LiPo sack every week. Out of exasperation I even offered to lend him one on one occasion but he refused.

I've used LiPo batteries for over 3 years with no problems whatsoever, and I knew nothing about them when I started. All I did was read the article below a few times and I was good to go, and i've asked a few times now for it to be a sticky in the electric section of this forum:

http://www.rchelicopterfun.com/rc-lipo-batteries.html

[Gayo]

FYI, the lipo fire on a race near Paris last weekend was because a central CVA axle worked loose and made a punch on the lipo. Bad luck, bad design of the car, but not really a lipo failure if you ask me.

[DCM]

Blogging equivalent of a Shock Jock.

Any store of energy is dangerous if stored/used incorrectly or provoked. The big difference now is that you have a nasty fire and smoke where as with NiMH's it would explode, showering the area in chemicals and shrapnel, neither are pleasant.

[Welshy40]

I agree these are dangerous but never had an issue luckily. Mind you I balance charge mine for every charge and know a lot of people dont so could be why this happens.

[DCM]

Indeed, but that is where complacency comes in isn't it, they 'perceive' them to be safe so relax.

[CHEVY]

nimh were dangerous if not charged properly
if you use things right ie charger and charge rate and right s setting you should be unlucky
to have any problems I charge my 1s in small sack inside big one

[mark christopher]

this is the response from the 12th brca chairman to a facebook page

"Mark Stiles In 3 years of national 1/12 racing (something like 20,000 packs charged) there have been 2 LiPo fires. Both were caused by incorrect charger settings, not 'dangerous' batteries. I wouldn't say that 1 in 10,000 is reason for too much concern. For the odd occasion it does happen we have the necessary safety measures in place"

And another well respected BRCA official

"In my garage I have some petrol, it's leathal stuff you know, been nown to catch fire quite easily.. we should probably ban it. As for this diesel stuff that's horid too.. Some folk have way too much time on their hands, 'stuff' is dangerous if we don't follow basic rules and apply common sense, other than that - Move On there's no story here."


fully agree with them both...

[SlowOne]

It's well documented that the manufacturing process for making LiPos is always going to end in some failures however careful people are with their LiPo ownership regimes. Puffing of LiPos is the first sign that those manufacturing issues and the growth of dendrites has come to a pack near you, and said pack should be gracefully retired via a bucket of salty water.

I've sat next to two LiPo fires and can comment as follows. In both cases the settings of the chargers were suspect, down to user error most likely. A sack is essential as it stops the hot debris spreading further afield and causing more mayhem. The achilles heel of the LiPo sack is the velcro, which melts and allows the tops to spring open allowing gas and flames to escape. The kevlar liners do their job, it's the velcro that allows escapes.

The 'box-style' LiPo sacks are next to useless as they have too many openings and the path of the hot gases is guaranteed to melt the velcro and the box pops open. The other fire was in a flat sack with the LiPo pushed to the bottom and the flap firmly closed. That did eventually pop open, but the delay was long enough for the bucket of sand to be on its way and the damage to surroundings was much less than the fire in the 'box'.

As for his 'procedural breakdown of how to respond to an RC [sic] fire' it is well known and proven effective. DO NOT try to get at it or anywhere near it with exposed flesh; cover the fire in sand. Never use any fire extinguisher as they don't work and water ones will only add the the problem - hot, water to steam, oxygen to feed fire, etc.

At 12th Nationals we have two, 2-gallon buckets of (fine, dried) sand in the pit area and one at the track area. As soon as a fire starts the bucket is rushed to the scene and its contents dumped on the LiPo. Once the sand coverage is enough to stop all egress of flames, smoke and debris, the area is left for at least 30 minutes until it is cleared up. Once 'dug out' the offending LiPo is left outside for at least three hours.

That the marshall is carrying the burning car and there was obviously no sand available is a huge minus for the organisers, as well as a common sense failure!

If LiPos have to go then we are all going to be miserable. These things go pop is all sorts of appliances, so is he really going to do without his 'phone, iPad, laptop and the countless other devices that use LiPos as back-up batteries? No. RC LiPos hold a lot more energy than the average 'domestic' LiPo, so when they go pop they do so with more vigour.

It's a sad article devoid of knowledge or facts and without alternatives that might make the abandonment of LiPos viable. It reflects poorly on the author as well as the sport. It is just the sort of canon fodder anyone hiring out a hall to us would need to withdraw the booking and put more pressure on the sport. Bad work...

[richm]

well said

[mattr]

TBH, if LiPos were really that dangerous and likely to explode at the drop of a hat, do you really think the most litigation happy country in the world would let people drive round with 30-100 kilos of them in the back of their cars? (Around 200kg for the full electric vehicles, tesla and so on)

No.

Cos they only tend to explode when abused or damaged. So auto manufacturers spend a proper fortune making sure they *can't* be abused and providing armoured casings so they can't be damaged.

[dodgydiy]

its a battery, of course its dangerous. anything that is a store of energy is dangerous. as for them saying about nimh not being dangerous or causing damage when failing, i can remember someone being taken to hospital from a meeting after a cell exploded and deposited hot metal in their eye... yes lipo's catch fire and are hard to put out, but as pointed out above, they are essentially a fuel source, they are powerful and like everything else powerful they need to be treated with respect and looked after properly.

[SlowOne]

Originally Posted by mattr

TBH, if LiPos were really that dangerous and likely to explode at the drop of a hat, do you really think the most litigation happy country in the world would let people drive round with 30-100 kilos of them in the back of their cars? (Around 200kg for the full electric vehicles, tesla and so on)

No.

Cos they only tend to explode when abused or damaged. So auto manufacturers spend a proper fortune making sure they *can't* be abused and providing armoured casings so they can't be damaged.

Not quite the best comparison. LiPos in the Tesla are the standard 18650 type that are contained in a metal shell not unlike the NiMh/NiCad batteries of old. Those have built-in relief valves and although failures are rare, they are contained.

Agreed, all batteries in electric cars are contained in a *cough* strong box (!) but nonetheless it is nothing like the LiPo cells we use with no fire-proof, reinforced container holding the cell.

Also remember that LiPo are the cells Boeing use in the 787 and have been the subject of a number of incidents over the last two years. All have been contained by the strong metal box the cells are in, but why have had more than their share of issues compared to the number in service? Is it that they haven't got the chargers sorted? Airbus have stayed with NiMh cells...

Nonetheless, in that litigious country you refer to, they happily sell RC Lipos and allow them to be shipped by air from China and fly them over their land. As you say, if they were that bad...

[mattr]

Didn't realise tesla were still using 18650s, the rumour was that they'd switched.
But tesla is the one electric/hybrid we haven't opened the battery box up to have a look at!

Didn't the Boeing issue come down to the batteries simply not being up to the job?