Lipo not so dangerous....

[neptronix]

If you take a group of 100,000 users of RC batteries, and a group of 100,000 users of laptop, cell phone, and cordless power tools. Which group do you think has more fires?

Good question. Probably the RC guys since it is a DIY affair, and they typically have more cells hanging around. Do you think the people with laptops or cell phones ever expect it, or have even been warned about the problem though? mobile phones & laptops have burned down cars and houses a plenty, not too hard to find info on google about that.

Same chemistry, same risk per cell.

 

[flyinmonkie]

Considering the statistics of lipo's in use and fires of all sorts of causes that have been reported... I am never going to drive again. Have you seen the statistics of users of automobiles and accidents? I mean seriously, I can't believe anyone drives. Every car on the road is a potential missile pointed right at you! You could be taken out at any time! Stop driving all of you, it will kill you you eventually!

Now seriously... There are risks with anything and you need to know what those are and how to eliminate, minimise, or isolate the risk.

 

[mxer]

Reading the comment about storing Lipo fully charged, has really put me off tbh.....

Last thing i want to do is get up for work 50mins earlier before i have to go just to top of my batteries It only takes me 25mins to cycle to work on a normal bike :lol:

Same for when i am at work, my last tea break is 3:00pm, having them hang around my work fully charged for the next 3.5 hrs is this classed as stored ?...There is no way i'm hanging around at the end of work waiting for my charger to bleep ......

I'll still use Lipo because of the advantages and versitilty, but with this statement and other's quirks that Lipo keeps reaping i'm really being put off.....Which is ashame

 

[neptronix]

Hey, just trying to be realistic..

For me, i have more range than necessary, so your situation would be no prob..
I'd keep my batteries charged to about 3.8-3.9v/cell avg, then stick them on the charger as i eat breakfast / have coffee for 'bout 1-20 mins.

Another thing is that non-lifepo4 cells generally don't like being stored at top voltage anyway. That stresses them out and leads to lower cycle life over the long term. Some cells seem barely affected by this, but some take a notable hit to their lives. RC Lipo ( lithium cobalt ) is one of those sensitive chemistries.

Run shallow cycles though and those suckers will provide ~600 cycles easy.

 

[mxer]

Yeah, Happy to charge in the morning as you said, breakfast, coffee etc, But for work charging it's going to have to be 3pm and used at 6pm....

I could go for more capacity, but my batteries would hardly be discharged by the time i arrived at work and would be left all day at around 4v per cell ? which is proberly worst ?..Or i could run at 120% and 40amp instead of 30 Knocking em down to about 3.9/8

 

[Philistine]

Reading the comment about storing Lipo fully charged, has really put me off tbh.....

Last thing i want to do is get up for work 50mins earlier before i have to go just to top of my batteries It only takes me 25mins to cycle to work on a normal bike

Same for when i am at work, my last tea break is 3:00pm, having them hang around my work fully charged for the next 3.5 hrs is this classed as stored ?...There is no way i'm hanging around at the end of work waiting for my charger to bleep ......

I'll still use Lipo because of the advantages and versitilty, but with this statement and other's quirks that Lipo keeps reaping i'm really being put off.....Which is ashame

I fully charge (I charge to 4.15V/cell on most chargers, 4.18/cell if using my Hyperions) all my packs, on my bikes, and I leave them like that in my garage. One pack has a 12S40ah pack, the other a 20S 20ah pack. I have never heard of the suggestion that you don't leave your bike fully charged (obviously if you are going leave it for a long time, like weeks without use, you should put it to storage voltage). But I ride my bikes everyday, so I just charge and leave them like that. I really think you are getting stressed over nothing, that is why I started this thread. I was put off Lipo for ages because of all the horror stories and fear that goes around. I don't recommend Lipo for people who are looking (at say) making a bike for their girlfriend to ride around on, for those type of people Lifepo4 is always going to be better - plug and play. But if you are smart enough to be able to stay within your charge levels and be sensible in the design of the pack/protection, I personally see no real risk. Even if you make regular dumb mistakes like me, it appears you can be fine.

 

[tef]

The smoke is just as damaging as the fire. I know the residues are very caustic and can ruin a lot of equipment if not washed down. Looks like you may have more damage than just the bike.

Ater a few hours all metal parts started to rust.
The wooden furniture was just before catching fire and is not useable anymore.
It took us weeks and a lot of money to clean and repair or replace most of it.

We were lucky that I parked the car outside.

I went through the trouble of creating a breakout board using a DB 25 pin parallel port connector. I will be able to monitor the packs with my balance charger without having to open the case. With 25 pins I can go up to 24S.

That is exactly what I wanted to do, but I was not fast enough :-( .

it sounds like you did not cycle test this pack to rule out the duds. Given that there is a 10% dud rate ( when i say this, i mean there is at least 1 bad cell in 10% of packs shipped ) you probably had at least 2 bad packs in there, just waiting to misbehave in some way.

Now i'm curious though, did you charge up to 4.2v per cell average? did you discharge below 3.6v/cell average?

I did discharge all packs with my Icharger to about 3.6V to check them, so one full cycle.
The charging voltage on my meanwell charger was set to 4.1V/cell.
The bike was not stored fully charged (3.9V) and I checked the voltages almost every day.

did you have any fuses between parallel sets of cells?

Unfortunately not between the paralleled discharge wires.
The balance wires were combined on a stripboard with very thin traces.


@marty, thanks for the tips.

The fire was last summer and we already cleaned and repainted everything.
I live in Austria (Europe).

 

[knoxie]

Like I said your fire could be caused by any connection within your pack, a fault on your pcb just about anything you cant just assume you had an internal cell fault as it is far more likely it was an external wiring problem.

Golden rules apply, never charge on the bike unless you care less about your bike, always store and charge safely (this is written on the side of the battery and it mentions charging on a concrete floor ), never bulk charge without HVC or cell monitoring, disconnect all monitors and BMS if stored for extended periods unless you are 100% sure of the current drain.

I am happy for folks not to use them thats their choice, I am happy to use them because I totally nullify the risks, there are far more risks in me being knocked off the bike, if people want to go to life cell then fine if you sleep better at night for it then thats good.

All battery chemistries are potentially volatile and I would recommend you follow the same practices no matter what, even lead acid, also dont forget your chargers a lot of battery fires have been started by the chargers esp those cheap Chinese chargers, I should know I have about 20 of them in my garage.

 

[emergence]

So as far as Tef's poor Fireballbike is concerned, the possibilities for the cause of the spontaneous combustion are:

- New pack syndrome? would a few more monitored test cycles negate this?

- Wiring short, which could be somewhat negated by putting fuses between the two paralleled packs to stop any large current between them. Also building a pack that can be opened and checked but does not require you to pull all the wiring out all the time. and again monitoring the new pack closely to check for wiring faults.

- unknown, cell rupture, damage or fault.

- just bad chemistry.

I can see that another issue with lipo could be having so much bms, fuses, fusecases, heavy guage wire, and wiring boards that you wind up back at a123 or lifepo4 weight...

 

[neptronix]

Why would a parallel group short to itself if the voltage is the same across all packs? no voltage difference, no current transfer..
The problem is usually in serial connections, where voltages are differing.

Shorts will, 99% of the time, melt the connector, wires, solder, or anything else in the pack before it actually does any kind of damage to the pack. This happens instantly.

There will never be an accurate analysis of what happened with his pack, it seems like there was not abuse, so i can only assume that bad new pack syndrome was to blame. Perhaps one was puffing, and the more it was charged, the more it got aggravated..

If you have a dud in 2.4kWh, the likelihood of a massive fireball is really, really high.
~2.4 kWh will be made up of approximately 24 6 cell 5AH packs.

That's 144 cells total.
And all it takes is 1 cell to light the whole thing ablaze..

this is why i am constantly beating people over the head to test their packs fully before even using them on a quality RC charger, such as the iCharger, or Hyperion series. Those tests involve a full discharge down to 3.0-3.3 while logging the cell voltages using software like the included logview. If you see a cell with a major anomaly, you don't use that pack, period. If a cell is misshaped or puffy from the factory, you don't use that either, period.

 

[hydro-one]

Ok my opinion is that your lipo was mad at you. You stated you had not riddin it for two weeks , can i ask what were you riding?>???? I know my pack would freak out.....

 

[tef]

I was riding my scooter with A123s, maybe that was the mistake :? .

 

[hydro-one]

This is the first documented case of lipo pack, and a very large one at that, being jealous of another pack of similar species. is your a123 pack bigger than your lipo was?

In all seriousness im pretty careful with mine, they are 95% in sight of me at all times, i only have one pack. and i baby it and only charge 1/2c , cellog it every few days. I have dented cells but they seem ok.

Be ready for fire. just toss that burning shiet out yo house!!!!

now shorting large wires close to lipo packs, that will burn u, as i found out when i plugged two packs together 184vdc......

 

[shock]

Maybe try buying a higher quality LiPo than the HK crap? Try blue LiPo or Gens Ace, much higher quality...

 

[E-racer]

Maybe try buying a higher quality LiPo than the HK crap? Try blue LiPo or Gens Ace, much higher quality...

Hundreds of us running HK lipo successfully can tell you that their lipo is anything but low quality. I've got hundred of charges on my 12s2p pack and it still maintains perfect balance.

 

[jonescg]

On the subject of hobbyking failure rates - I think I know why.

You guys are buying 6s packs right? This means that for $55 or so, you are getting 6 cells that have been assembled by a human. That human might have picked up a dud cell, overheated it while soldering, or not soldered them together properly. All up, there is 6 times the probability of a failure compared to buying bare cells.

I have been buying the Turnigy 40C individual cells and putting them together how I please. This way, a machine takes bulk ingredients and winds them up into a cell which must have a copper tab resistance welded to one side. Basically, only one times the probability of a failure. What I do to them is my problem, and may well lead to ten times the fail, but that's my problem at least :lol: Mind you they still haven't replenished their stocks of 5 Ah 40C Turnigy cells :?

 

[E-racer]

That human might have picked up a dud cell, overheated it while soldering, or not soldered them together properly. All up, there is 6 times the probability of a failure compared to buying bare cells.

I couldn't agree more. I debated getting bare cells but my budget allowed for 10ah of bare cells or 15ah of 4s packs so I decided on 4s packs. It is unfortunate that the bare cells are not the best deal considering they come with the least amount of added stuff.

 

[miuan]

I couldn't agree more. I debated getting bare cells but my budget allowed for 10ah of bare cells or 15ah of 4s packs so I decided on 4s packs. It is unfortunate that the bare cells are not the best deal considering they come with the least amount of added stuff.

On the other hand, it's fortunate that the 4S hardcases are so cheap you can literally dump every 4th pack and still have a bargain + puncture resistant casing. Puffing is hard to detect, but you can still strip them off the cases and assemble them compressed as you wish.

 

[boppinbob]

I just ordered ammo cans off ebay because of this thread and I'm only going to ride my lifepo4 bike to work now. This thread freaked me out, thanks guy's. I am glad I sacrificed a little beauty for a removable battery box.
Regard's, Robert Pate
PS I just can't give up my lipo altogether, though, because the speed is such a rush. I'll just be a little more cautious now.

 

[E-racer]

I'm much more worried that there are millions of children playing with these lipo batteries. I imagine most have probably not been properly educated on the subject matter. Personally, I know and abide by the lipo rules 3.7-4.16. Keep the cells in this range every charge, every time.

 

[neptronix]

I'm much more worried that there are millions of children playing with these lipo batteries. I imagine most have probably not been properly educated on the subject matter. Personally, I know and abide by the lipo rules 3.7-4.16. Keep the cells in this range every charge, every time.

You're missing out on 3.6v, there is some extra range there.

Stop discharging at the cliff.

As for children and RC li-co batteries, those batteries are so small that an explosion would really pale in comparison to what we run. Guys at hobbyking prolly think we're off our rockers..

 

[E-racer]

Yea I use 3.7 as a safety. I though you were right about kids using small lipo, unfortunately that is not true. Kids with the monster trucks sometimes run 2X 6s 5ah packs which is plenty to burn up rather violently. In all honesty I'm ready for HK to embrace us EV guys with some 20ah modular hardcase cells or something of the sort :-D

 

[neptronix]

The idea of a kid charging a lipo that big gives me the creeps.
Hobbyking really needs to put out some high discharge rate NMC lipo cells.

Li-co needs to go.

 

[E-racer]

Yea but you just cant beat 12s 15ah or 750w/h for >$225 in 4s packs. I'd love to see NMC HK batteries, more cycle life would always be welcome.

 

[izeman]

have you ever thought about how MASSES of lipos are stored at the shops?
imagine a warehouse full of lipos!? or do you think hobbyking stores each of them in a seperate ammo box? remember: those are charged at 3.8v. so they contain a lot of energy ...
if only one of those explodes there may be a big ball of fire that can be seen from australia
what i want to say: why do we take so much more care than "professionals"? or do you think that a NEW lipo is NO risk at all?