are lipo batts safe?
- Thread starter ev_nred
- Start date
Kepler
10 MW
Most of the accidents with LiPos has been through incorrect charging procedures. If you are new to LiPo's I would suggest to use RC type chargers. Really quite straight forward to charge with these charges. The reality is that it needs to be reasonably safe otherwise they simply couldn't sell them.
liveforphysics
100 TW
AFAIK, not a single (unintentional) Lipo fire has happened to any members of this board. Not for lack of giving it a good shot either.
Andje
10 kW
- Joined
- Aug 25, 2010
- Messages
- 779
a lot of the experts tend to point out that lipo is really no more dangerous then any other battery when being handled correctly. If you are handling it incorrectly, then yes it is very dangerous and can burn your house down... but so can ANY battery over 24v if it's being mishandled and mischarged. The point is that it is like any other battery technology; used properly with in it's parameter's you will not experience any sort of spontaneous combustion.
There are plenty of youtube videos of various different lipo's being tortured to death, and of what kind of abuse is dangerous for different cells. "Dropping" the bike shouldn't ever result in a fire unless you dropped it onto something that pierced the cells or short circuited the battery. Since pouch cell Lipo's should be contained inside a metal case to prevent expansion and prolongue cycle life, this layer can simply be made thick enough that standard "dropping" would never be a concern. With round cells such as A123 or prismatics, the casings themselves obviously offer some protection, and again they should simply be mounted in container that keeps them safe.
With all that said, I suppose it's inevitable with the growth in popularity of Lipos that we will eventually see an ebike vs car accident that results in the combustion of the bike. Imho, the rider of the bike is unlikely to ever be in true danger specifically from burning lipo in such an accident; they combust fast and frighteningly vigorously but not explosively or outside of human reaction time. Far more likely that a diy'er frocks up the wiring harness or charges them too long in terms of likelihood of an accident.
I echo what LFP said
There are plenty of youtube videos of various different lipo's being tortured to death, and of what kind of abuse is dangerous for different cells. "Dropping" the bike shouldn't ever result in a fire unless you dropped it onto something that pierced the cells or short circuited the battery. Since pouch cell Lipo's should be contained inside a metal case to prevent expansion and prolongue cycle life, this layer can simply be made thick enough that standard "dropping" would never be a concern. With round cells such as A123 or prismatics, the casings themselves obviously offer some protection, and again they should simply be mounted in container that keeps them safe.
With all that said, I suppose it's inevitable with the growth in popularity of Lipos that we will eventually see an ebike vs car accident that results in the combustion of the bike. Imho, the rider of the bike is unlikely to ever be in true danger specifically from burning lipo in such an accident; they combust fast and frighteningly vigorously but not explosively or outside of human reaction time. Far more likely that a diy'er frocks up the wiring harness or charges them too long in terms of likelihood of an accident.
I echo what LFP said
Lessss
1 MW
No they shrink your testicles if you think about buying them.
AussieJester
1 TW
liveforphysics said:
Only (unintentional) fire i have seen on this site on an ebike was a Lifep04 pack burning, i dont recall the details but the member had time to get off the bike and take pics of his smoking battery pack...
Lipos are as safe as the person using them, treat them right and they are safe.
KiM
I'm new to LiPo, and I haven't set one on fire yet, but...I have damaged a pack by discharging it too low.
I read a lot, and I can't verify the info I'm about to provide, but, heres the rumors I've read about what causes LiPo fires.
1. LiPo smart chargers are expensive. Some users have bought a 6S-22.2V (nominal) pack, which can be safely charged to 4.1V per 6 cells = 24.6V for the pack maximum. Some users figured "volts is volts" and they bought a $10 24V charger from Walmart, (which they may not realize it actually charges the pack to around 26V), and if its a 'dumb' charger, it charges until you turn it off = fire.
2. If you discharge a LiPo pack too low (3.4V per cell is often cited as being reasonably safe for long pack life), and you go below 3.0V per cell (for the popular 6S-22.2V pack), 3.0V X 6 = 18.0V...then, there is the possibility that one of the cells may suffer a polarity reversal (am I saying that right?). Then when you put it on the charger, it will begin shorting, leading to heat-expansion, leading to tearing of cell internal divisions, leading to a rapid runaway short = fire
3. Early LiPo cells had a much lower C-rate and could not put out the peak amps that the current common 25C+ packs can. Drawing more amps from a pack than it is designed to output (for any battery chemistry) leads to the pack heating up. LiPo has been popular in the RC market, and as a result the packs that have been the most popular are as light as possible. This allows the buyer to add as much or as little protection to the pack as they want, weight and bulk being the penalty. The internal cell divisions are light and fragile, (and were more-so in the past). Such thin internal divisions could not take much heat-expansion. Heat-expansion can result in tearing and runaway shorts = fire
I don't know if any of the things I've just listed are accurate, just passing along unsubstantiated rumors and vicious allegations I read...
I read a lot, and I can't verify the info I'm about to provide, but, heres the rumors I've read about what causes LiPo fires.
1. LiPo smart chargers are expensive. Some users have bought a 6S-22.2V (nominal) pack, which can be safely charged to 4.1V per 6 cells = 24.6V for the pack maximum. Some users figured "volts is volts" and they bought a $10 24V charger from Walmart, (which they may not realize it actually charges the pack to around 26V), and if its a 'dumb' charger, it charges until you turn it off = fire.
2. If you discharge a LiPo pack too low (3.4V per cell is often cited as being reasonably safe for long pack life), and you go below 3.0V per cell (for the popular 6S-22.2V pack), 3.0V X 6 = 18.0V...then, there is the possibility that one of the cells may suffer a polarity reversal (am I saying that right?). Then when you put it on the charger, it will begin shorting, leading to heat-expansion, leading to tearing of cell internal divisions, leading to a rapid runaway short = fire
3. Early LiPo cells had a much lower C-rate and could not put out the peak amps that the current common 25C+ packs can. Drawing more amps from a pack than it is designed to output (for any battery chemistry) leads to the pack heating up. LiPo has been popular in the RC market, and as a result the packs that have been the most popular are as light as possible. This allows the buyer to add as much or as little protection to the pack as they want, weight and bulk being the penalty. The internal cell divisions are light and fragile, (and were more-so in the past). Such thin internal divisions could not take much heat-expansion. Heat-expansion can result in tearing and runaway shorts = fire
I don't know if any of the things I've just listed are accurate, just passing along unsubstantiated rumors and vicious allegations I read...
Kepler
10 MW
Actually I think LiPo charges are quite cheap. $18 for a 50W charger that will even balance charge is a bargain.
I use 2 x 400W Turnigy charges at the moment and charge 5 x 6S 5ah packs in parallel per charger. $70 a piece for these charges. Add a 50A power supply for around $200 and its still a cheap way of quick charging 1250 w/hrs. I balance charge about every 10th charge using parallel balance charging boards. Works very well. Never lost a cell yet.
Also full charge for a LiPo is 4.2 per cell and is what RC charges charge to. People using Meanwell type charges tend to be a little more conservative and charge to 4.1 per cell.
I use 2 x 400W Turnigy charges at the moment and charge 5 x 6S 5ah packs in parallel per charger. $70 a piece for these charges. Add a 50A power supply for around $200 and its still a cheap way of quick charging 1250 w/hrs. I balance charge about every 10th charge using parallel balance charging boards. Works very well. Never lost a cell yet.
Also full charge for a LiPo is 4.2 per cell and is what RC charges charge to. People using Meanwell type charges tend to be a little more conservative and charge to 4.1 per cell.
Jeremy Harris
100 MW
As others have pointed out, the whole LiPo safety thing has been blown totally out of proportion by a very tiny number of incidents, mainly caused by gross abuse of the cells.
When you look at the hundreds of millions of LiPo cells in 'phones, laptops etc and then look at the extremely low incidence of battery related incidents, it tends to put things into a better perspective,
In terms of cell abuse, then I think the RC crowd are far more likely to have problems than we are. They operate at average discharge rates that are around three to ten times those we run at (draining a pack in less than 10 minutes is pretty normal for the RC guys), they charge as fast as they can in the field (because they want to fly again as quickly as possible) and they subject their packs to levels of impact damage, shock etc with minimal pack protection, because they can't afford added weight.
Even so, the incidence of cell fires amongst RC users is now pretty low, so low that it hardly ever crops up on their discussion boards as a major topic.
Like any high energy storage system LiPos need to be installed and managed safely, but the same is true of the fuel tank on a vehicle, and it's associated pipe work. Most incidents seem to be as a result of installation problems, so understanding what's needed to make an installation safe is important, particularly when it comes to physical protection and wiring.
Jeremy
When you look at the hundreds of millions of LiPo cells in 'phones, laptops etc and then look at the extremely low incidence of battery related incidents, it tends to put things into a better perspective,
In terms of cell abuse, then I think the RC crowd are far more likely to have problems than we are. They operate at average discharge rates that are around three to ten times those we run at (draining a pack in less than 10 minutes is pretty normal for the RC guys), they charge as fast as they can in the field (because they want to fly again as quickly as possible) and they subject their packs to levels of impact damage, shock etc with minimal pack protection, because they can't afford added weight.
Even so, the incidence of cell fires amongst RC users is now pretty low, so low that it hardly ever crops up on their discussion boards as a major topic.
Like any high energy storage system LiPos need to be installed and managed safely, but the same is true of the fuel tank on a vehicle, and it's associated pipe work. Most incidents seem to be as a result of installation problems, so understanding what's needed to make an installation safe is important, particularly when it comes to physical protection and wiring.
Jeremy
dogman dan
1 PW
I totally agree, the real hazard is any wiring carrying voltage above 12v. Hell, even a 12v wire that contacted a hot exhaust burned my 65 international pickup back in 1978. It's not the battery that catches fire in 99% of fires, but the combustible thing touching wiring, including the wire insulation. Once that wire becomes a heating element, it's game on. So build so nothing rubs through. Don't put a working charger on carpet, etc.
LI-ghtcycle
10 MW
I will say safer than gasoline, but different, needs a good deal of self-educating before handling, but to be honest, I doubt that all the cell phones around the world with the same battery tech (albeit smaller, but when else do you have a LiPo pack next to your ear?) have done anyone any reasonable harm from batteries cooking off.
I was really scared after watching the videos on youbube, and only considered LiPo when I realized how much I was paying for a single 28V Dewalt pack and all the trouble I was going to to get them to work, and how much more cost effective LiPo was, then when I heard about the new nano tech turnigys, I took the plunge!
I can't speak from anything but a wet behind the ears novice with a good dose of cation and using high quality proven charger, and I balance my cells every charge. I am only 5 charge cycles through my 6 packs, but I can say that by following the expert advice here on ES, that not ONLY have I not damaged a pack or even a single cell in a pack, but I have not even had the packs, wires, ESC or motor even heat up under 118A draw (momentarily burst, constant more like 60A)!!!
I had a LiPo pack that had puffed up but still charged and discharged normally given to me by my local hobby shop, and did some torture testing of my own. This pack wasn't over charged, but just had a nominal charge and I set about shooting it with my high powered .22 pellet rifle (same power as a .22 short).
I then dropped it in a bucket of water. NO reaction, no nothing! I was really disappointed! :lol: I was expecting a firework show. Mind you I was blowing holes ALL THE WAY THROUGH this 4s 3000 mah pack, not just denting it. I even put holes through the puffed up cell and it didn't let out so much as a "pop".
I'm still planning on putting either a metal or high temp plastic case on my 4s 6000 x3p (15v 18ah pack) but for now I have a LiPo charging bag for extra insurance, and no problems or worries so far.
I think you have a MUCH greater chance of problems with a motorcycle or gas bike, I'll never forget the race where some guy's fancy schmancy synthetic oil started leaking from the heads of his FZR Race bike spraying his leathers on the legs and starting to burn, and here his is just riding normally while all the corner workers are trying to flag him down!!!
You NEVER saw someone do the "ants in my pants" dance on a bike going 60 - 80 MPH so comically!! (His leathers protected him, no injury but man it was scary and funny!!!
)
Buy a good quality proven charger with a good track record, use a pyrex (corning wear) cooking pan or LiPo charging bag and DO NOT LEAVE while charging, have an exit strategy if they were to catch fire (very rare if you follow the previous) so you can get them out of the garage fast.
Don't charge them in the living room, do it somewhere it can take some heat or if you don't mind taking the chance of losing $300+ of good charger & power supply, charge in a BBQ pit or other such place outside and let 'em rip.
I also think a big part of this is being really kind to them, don't do more than 80% discharge EVER, and in the first 10 cycles no more than 50% (if it's cold maybe only 30% durring the first 10 charges)
I'm no expert, but I am careful, and I paid extra for really good LiPo instead of the cheap stuff, and I haven't had ANY issues yet.
I was really scared after watching the videos on youbube, and only considered LiPo when I realized how much I was paying for a single 28V Dewalt pack and all the trouble I was going to to get them to work, and how much more cost effective LiPo was, then when I heard about the new nano tech turnigys, I took the plunge!
I can't speak from anything but a wet behind the ears novice with a good dose of cation and using high quality proven charger, and I balance my cells every charge. I am only 5 charge cycles through my 6 packs, but I can say that by following the expert advice here on ES, that not ONLY have I not damaged a pack or even a single cell in a pack, but I have not even had the packs, wires, ESC or motor even heat up under 118A draw (momentarily burst, constant more like 60A)!!!
I had a LiPo pack that had puffed up but still charged and discharged normally given to me by my local hobby shop, and did some torture testing of my own. This pack wasn't over charged, but just had a nominal charge and I set about shooting it with my high powered .22 pellet rifle (same power as a .22 short).
I then dropped it in a bucket of water. NO reaction, no nothing! I was really disappointed! :lol: I was expecting a firework show. Mind you I was blowing holes ALL THE WAY THROUGH this 4s 3000 mah pack, not just denting it. I even put holes through the puffed up cell and it didn't let out so much as a "pop".
I'm still planning on putting either a metal or high temp plastic case on my 4s 6000 x3p (15v 18ah pack) but for now I have a LiPo charging bag for extra insurance, and no problems or worries so far.
I think you have a MUCH greater chance of problems with a motorcycle or gas bike, I'll never forget the race where some guy's fancy schmancy synthetic oil started leaking from the heads of his FZR Race bike spraying his leathers on the legs and starting to burn, and here his is just riding normally while all the corner workers are trying to flag him down!!!
You NEVER saw someone do the "ants in my pants" dance on a bike going 60 - 80 MPH so comically!! (His leathers protected him, no injury but man it was scary and funny!!!
)Buy a good quality proven charger with a good track record, use a pyrex (corning wear) cooking pan or LiPo charging bag and DO NOT LEAVE while charging, have an exit strategy if they were to catch fire (very rare if you follow the previous) so you can get them out of the garage fast.
Don't charge them in the living room, do it somewhere it can take some heat or if you don't mind taking the chance of losing $300+ of good charger & power supply, charge in a BBQ pit or other such place outside and let 'em rip.
I also think a big part of this is being really kind to them, don't do more than 80% discharge EVER, and in the first 10 cycles no more than 50% (if it's cold maybe only 30% durring the first 10 charges)
I'm no expert, but I am careful, and I paid extra for really good LiPo instead of the cheap stuff, and I haven't had ANY issues yet.
Drunkskunk
100 GW
I use Lipo for RC and my bike, and I've got 5000 miles of Lipo use on my bike. They as safe as Gasoline.
But I wouldn't refill my lawnmower in the house, or in my car, or leave gas pouring into it while I was taking a nap.
I've not had a fire. I have had incidents were there could have been a fire if I hadn't been watching, Cells puffing up rapidly, smoke, ect. But all of it was preventable by keeping an eye on the batteries as they charged. But I've had hundreds of Lipo cells, and been charging them for years.Trouble is rare.
Droping your bike won't cause a Lipo to explode. Dropping the pack and letting it skid 50 yards across broken glass and gravel might cause a pack to rupture and burn. But the same could be said about a motorbike's gas tank. Most of the cells are in foil pouches, and safe as long as they don't get punctured.
But the pouches can get bent safely. I've had to retrieve a Lipo from the ground with a shovel after I managed to slam a plane into the ground at insain speeds. That battery went on to fly many more planes.
Lipo are safe if treated with respect.
But I wouldn't refill my lawnmower in the house, or in my car, or leave gas pouring into it while I was taking a nap.
I've not had a fire. I have had incidents were there could have been a fire if I hadn't been watching, Cells puffing up rapidly, smoke, ect. But all of it was preventable by keeping an eye on the batteries as they charged. But I've had hundreds of Lipo cells, and been charging them for years.Trouble is rare.
Droping your bike won't cause a Lipo to explode. Dropping the pack and letting it skid 50 yards across broken glass and gravel might cause a pack to rupture and burn. But the same could be said about a motorbike's gas tank. Most of the cells are in foil pouches, and safe as long as they don't get punctured.
But the pouches can get bent safely. I've had to retrieve a Lipo from the ground with a shovel after I managed to slam a plane into the ground at insain speeds. That battery went on to fly many more planes.
Lipo are safe if treated with respect.
