faulty 18650 cells caused a fire and I think I found out why!
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- Опубликовано: 11 сен 2024
- High-Resolution photos & more information as I find it.
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Pete
#diypowerwalls #hbpowerwall #18650ed #diypowerwall
Monitoring my packs with a Flir just climbed up the list, to the top.
Don't forget all the other little things too :) Thermal is only part of the equation
More thermal monitoring on a day to day basis might help. Just how a bms monitors one area on a pack you should be able to monitor multiple areas. And some bms after this slew of videos might have a way of flagging potentially faulty cells due to charge and discharge or thermal properties
Continuous monitoring with thermal camera connected to raspberry pi. Suspicious differences in images or detected hot spots automatically & immediately send via email together with a loud buzz alarm. Hardware cost $500 USD max? Something like a flir one pro should be enough I think or similar resolution/sensitivity.
@@bullglar can likely be done with stm32 for less than 200 and work in areas where flir won't. Either due to idle power draw of the cams and pi, or because the packs inside a heat shrink or metal enclosure. Your idea still has merits. Would consider it even for dodgy inverters n such. Just like stm32 with can bus more as you can integrate your bms, inverter, and battery monitoring on a single bus, and then have a chip like an stm32 with WiFi for exporting data, a web ui, alarms and so on. Also works for remote management
@@HBPowerwall We need a list
For people who can't afford a thermal imaging camera, you can get thermochromic colour changing sheet or even heat colour changing stickers.
They are available in different temperature ranges. You can stick a small piece to each visible battery so you can see any temperature change with your eyes.
Or you can just run the thermochromic sheet over the packs slowly looking for hot spots.
Alternatively, labels for thermo printers turn from white to black when they get very hot. They won't display the small variation of increased temperatures but if they get over 60 celsius, they start changing colour. At 100 celsius, they turn black. The colour change is permanent on these stickers so you can catch occasional faults that you may have missed occurring.
He caused a short at the last part of the video when he pushed down on that battery pack xD 9:30
Well !@#$%^&*( me that didn't take long... but since your the winner - ruclips.net/video/4ED_FRcfG2Y/видео.html
yep. I just saw it too. was that one of the fuse wires shorting?
@@HBPowerwall lol
@@HBPowerwall you could even hear it sizzle I think :0
Should the fuse burn and not cause fire
Just my 2c, putting cells in water did save the pack from complete thermal runaway. So good job for that one, even the fire officials have said that when it comes to lithium battery fires all they can do is douse the battery with water to try and cool it to stop thermal runaway, as when the cells get to that point, they are producing their own oxygen. There is not much point in trying to suffocate something that produces its own oxygen....
Probably could put it in oil big drum of oil and recover it
Hey Pete, thanks for sharing. Looks like this 0V cell that will not accept the charge and keeps getting hot, is headed for a dead short. Jack Rickard did a detailed video on dendrite formation on over discharged cells. He talked about the dangerous of charging the dead cells with pierced separator between the anode and cathode, how the dissolved copper looses its integrity and could be deposited anywhere within the cell. This leads to thermal runaway, next time the cell is being charged. If it starts taking a charge to 1 or1.5V and then it suddenly reverses, that is the end of this cell, it can not be charged. He mentioned, if it goes in to thermal runaway, a cathode gives off free oxygen at 150-180 deg.C when it is burning, so it is really difficult to put out. Anything getting hot for whatever reason in a pack like this is not a good sign.
Now the funny part is that the 0 volt cell was not the hot one. Watch the video again.
@@bullglar well, at 3:50 Pete says " and this one here is completly 0 volts, and that's the heater"
Please watch the video again
@@AdamBoguski I know and it's a mistake on Petes side. Count the cells ftom the left. Compare flir image vs normal. The heater has 3.7xx volts.
The hot cell is the eight in place (counting from the left) and the zero volt cell is the sixth in place (count from the left)
A good friend of me called me one day and she was totally in panic while talking. She said that she just started charging an 18650 for her e-cigarette as I do too once or twice a day. But her cell immidiently got hot and even got hotter in her hands after removing it from the charger. She was not knowing what to do and I just said: Go to your kitchen get a cup fill it with water and put it inside with the negative side down and set the water level that high so that the cell's positive side is not submerged to prevent water from entering and to remove the heat and put the cup outside. The cell was ony 2-3 years old but massive used due to one complete cycle every day. -greetings from Germany!
EXACTLY. Why I bought a thermal imager BEFORE I started my build 👍🏻
nice work, and good call!
8:11 I love that tough love advice, it’s so true. Do it right or not at all. Like my friend says to people who travel - ‘If you can’t afford travel insurance then you can’t afford to travel’.
I think I was too harsh hehe but it's needed I think.. Some stupid people doing some dumb shit lately
Idea: Bond a 1N4148 diode per battery, then measure its forward voltage drop - which varies ~ 2 millivolts per degree C. These diodes are *really* cheap as temperature sensors - 2 to 4 cents per in quantities of a hundred. Use some multiplexed A-D converters, with an (Arduino) to keep track of and warn…
The lesson here is these things need constant monitoring due to the cells being of unknown age, condition and also being mixed with other cells of different design characteristics.
THIS...
Yed
I’ve had my Leaf wall operational about a week now and watch it like a hawk, thou I’m confident the cells are not going to be an issue, I’m more worried about the low voltage wiring. I need a thermal camera.
Agree, you should never mix different cell brands in one pack, that is Battery 101 knowledge. These packs should not have been built like this using different cell brands
If anyone does mix different cell brands, ages, or models each cell aught to have some kinda thermal sensor. Maybe someone will make a bms or can bus addon board that can multiplex a few thousand thermal sensors. Till then just don't do it
Great work on this and thank you for spending so much time trying to learn and teach us what you found out to help the community be safer. What I have taken away from this is that my builds will have the 18650's both fused properly and enclosed in a metal housing - regardless of how good I think my build is. Keep up the great work.
To underline what Pete said about dumping the batteries into a big bucket of water.
A fire extinguisher will only buy you time to get the battery to the big bucket of water, it takes hours of soaking in water the fully quench the reaction (even if the cell can has burst).
this!
Don't consider 30 degrees to 40 degrees is ok. Any difference in temperature in a pack sitting idle for a while means there are dentrite formation between anode and cathode. These can burst into flames anytime. Get rid of all those heater cells right away when you find one.
Break the fuse on the negative end of the hot cell. Get your digital multi meter(DMM) and set it to current/amps. Connect the DMM red lead to hot cell negative, and black lead to the copper bus bar. If it shows a negative value the current is flowing backward through the hot cell and shorting the bus bars from + to -. A diode on every cell would stop reversing shorts, the problem is diodes have a voltage drop.
As an experiment you could get an old cell that gets hot and connect it with clip-on leads to the + and - of a pack and check for reversing current and see if it catches fire - clip leads allow you to yank it fast - .
This is why I mentioned self closing steel boxes a year ago. I got the idea from kero part washing tanks with a soldered link on the lid that melts and shuts the lid if the kero catches fire. You can see them at Supercheap stores.
If it's not reversing current but just internal resistance heating the cell, you should switch to a low temp solder that will melt and disconnect the fuse when it gets hot. I think it's bismuth based solder, but you'll have to look it up.
This melts at 118ºC
www.digikey.com.au/product-detail/en/chip-quik-inc/SMDIN52SN48/SMDIN52SN48-ND/8681827
@SidneyCritic ComedyHound
- If you add a reverse blocking diode to every cell, then how can you CHARGE that cell ?
@@MrSummitville Opps, I think you're right. If the higher potential voltage is on the outside of the diode it can never flow into the battery to charge it.
I guess low melting point solder might help to disconnect a cell if it overheats, because at 118ºC it shouldn't be on fire.
It would be good to purposely blowup cells while it's connected to an amp meter that can sense direction, then we can see what the failure mechanism is.
Fireman here:
A Fire extinguisher, as a rule of thumb, lasts about the weight in kg of the filling in seconds. It doesn’t really matter what kind of filling, whether CO2, water, foam or powder
So if you have a 6kg CO2 Fire extinguisher, like they are common here in Germany, that thing will blast for 6 seconds continuously, not even close to a minute!!
That’s why you should always use a fire extinguisher by bursting it in short pulses, watch what happens to the fire and then make the next pulse
A fire extinguisher would have been a waste of time in this situation and most lithium battery fires.
@@gemrough no, depends on the stage of fire. Cooling always helps as cutting off the line to oxygen to lower the temperature.
@@typxxilps Would any type or size of fire extinguisher have actually stopped this?
@@MrSummitville A really big one.
Regular fire extinguishers work mainly by suppressing combustion, e.g. by producing ammonia or CO2 to block oxygen from reaching the fuel.
However, with a Li-ion battery fire, little combustion in O2 is actually occurring, so that type of extinguisher will do nothing. Basically, you need to (1) cool the cells as much as possible to prevent other cells from going off, and (2) isolate them from combustibles to prevent them from setting other things on fire. Flooding with large quantities of water is probably the best, or you could dump it in a bunch of sand or baking soda.
Maintenance wouldn't have been such an issue if known troublemakers like the Sanyo 18650's were left out.
Almost 2 years I finally had enough identical cells to make a 1p14s battery, unfortunately they were Sanyos from drill batteries.
I also had 3 Sanyo heater cells to experiment with (under controlled conditions), after a few experiments I now had 6 heater cells, and 3 with poor capacity or other issues.
Started with 36 cells old cells, ended with 14 good ones, so 67% failure rate (yes even the spare cells failed).
Some got hot when charged, some heated up when discharged, I think some even acted up with left on a shelf.
Technically Pete is right about this being a Maintenance issue, if you count going back and rebuilding the packs without the sanyos as Maintenance.
So you need a $300 thermal camera, $200 worth of cell chargers, $200+ for even a basic monitored BMS, plus a smoke/fire alarm, this is not a cheap project anyway with the cost of obtaining the cells.
I still think just obtaining ONE big battery you can repair/modify to suit your purpose, or just buy new/unused matching cells is a much better option.
The part that amazes me about this whole scene, is that so many are prepared to learn, but not learn certain things.
Programming an arduino is fricken simple. Yet people would rather pay exorbitant money for the latest chargers and BMS systems. I understand it's more of a learning curve and I'm lucky in that I started young with electronics.
But there's so much misinfo (it's getting better) out there, and so many simple solutions to some of these problems.
I might even start building some solutions and selling them, because the cost of chargers and the like, are beyond the pale for what they are.
when you have hundreds of components, you are more susceptible to a single failure, that's what put me off 18650. Went down the LiFePo route after an unpleasant 16 battery lead-acid experience.
I am currently leaning against lead acid in favour of any lithium... What was your "unpleasant experience"? I would really like to know if there are any cons I'm unaware of.
Love my LiFePO4 cells as well! LTO as well are amazing (overpriced, but safer by far).
@@wildhavenoff-grid3587 loving my LTO pack :) No worries using at freezing temps right now.
Any storage of energy poses a risk, think about a can of gas. Now, lead acid battries vent highly flammable gas during charge.
@@chriss160 yes... But those gasses can be vented easily. Especially with AGM that does not vent much at all and probably have an attachment for a hose it can vent through.
Personally I'm more into flooded cells because they seem to be able to handle more abuse. But for my use case (stationary, semi off grid) weight and space is not an issue.
I would not pick LA for most hand tools :)
Maybe a good pinpoint is set chargers to not exceed 3,96V/c for dual reasons: longevity and avoid overheat in weaker cells that can not tolerate the upper range voltaje? With programmable solar charge controllers is easy to do, but with some chargers like ISDT the lower voltage of mine is 4.05V...
Hi. I'm thinking that if the BMS was working hard to keep the balance then it must be a matter of watch your BMS to prevent a failure like this. I have a 160P setup and the balancer is not active at all. So my 7S is in perfect balance. Within 0.05 volt (with my Fluke). If my balancer goes nuts, then I know I have an issue and can take the needed action. If I understand Pete here........ by the way. My thermo cam don't show anything to be concerned about. Keep up the good work Pete.
Peter, Thank You for taking Your time to do this research. You have the defective cells, so without Your work I will not be any wiser. :)
Thanks for sharing and keep in mind. As they have found with Tesla's even after a fire has been put out keep them in a fire proof place for several days as they can re-ignite. One fire department called back several times to put out a Tesla fire in a tow yard. But that could have been ongoing shorting of the wiring and metal from the crash.
Cheers Pete, I just brought a thermal camera and will now check my setup monthly.
Or more often! Either way have fun with your new toy ..
@@HBPowerwall You might want to use your camera to find the dog steamers before you step in them.
more fun with the wifee heheheh
I plan to have a thermal camera mounted permanently, looking at the rack.
@@jimmyb1451 I think this is the way to go! Best if all the modules are turned so the camera can see the top of every 18650 in the pack. Maybe get really advanced with some software to alert you "Hey, this cell was 2 degrees warmer than average, now it's 5 degrees and rising. You'd better get out here and do something! "
What I do is to leave cells for 6 months at 3.8V before putting them into the pack. Plenty of reclaimed cells are 0V after 3 months. Some after few weeks. I would only use cells with voltage above 3.7V
i totaly agree on the notion that the smartest thing to do is to put the burning material, this time a chemical/electrical burning object in water, this cools down the object and as you said it has an ability to stop chemical reactions, a fire extinguisher
last only a few seconds at max, a 6 kg/liter extinguisher lasts for exactly 6 seconds with continues load/usage all depends on what type of extinguisher you have/use. waterbucket was the definitive smartest move!
Yup just one cell.
They rocket motor and while they are burning up they weld the fuse and take out the whole parallel block... I check my cells weekly....
All I have is miss-matched old batteries.
And the fire extinguisher is rubbish.
Take it outside wait for it to burn out..
I’ve learned mine are in aluminum boxes with vent pipes that go outside and all my batteries are in my shed..
Sounds like you've put some thought into your build
185👍's up thanks again for taking your time for us all to be with you for the rest of the story
Thank you too
If you are going to construct a battery like that (40P2S) with the negative and positive side next to each other (not a great idea IMO), you need some kind of insulator between the 2 cells. Just a small air gap is not enough.
6:46 Damn, hit - you sank my battery ship!
Thanks for all the info you share on You tube, been following your efforts for a while now. Hate to be the fly in the ointment, at 2:15 you show the hot cell (8 from the left of the pack) and when tested at 3:45 it was 3.728v but the cell that tested at 0.0v is cell 6th from the left of the pack. The hot cell location doesn't match the location of the 0.0v cell. Maybe the fuse wire didn't melt because there wasn't any high current between cells, rather an internal failure within the individual cell.
Noticed that as well 😋
Nice catch. So to measure just the voltage is useless. We need thermal picture or continuous temperature for every cell, automatically every minute, machine compared results, in case anomaly detected send an alarm immediately.
Bucket of water was the Best/Smartest thing! I wonder if I should pull my packs to take a thermal camera look!
@@newscotlandtv Water was the best thing...
@@newscotlandtv It's a lithium salt, not elemental lithium so it's not going to react. Water is the best option to cool the cells since water boils at 100C so even if the water is boiling the cell is being kept cool enough to stop and further prevent thermal runaway as long as the water doesn't evaporate completely.
@@newscotlandtv But you are still dropping that temperature and stopping the thermal reaction. Welders will quench hot work in water to cool it down in some cases so I fail to see the issue. You also need special equipment to do things like underwater welding and have any hope to maintain a decent arc. As long as you keep the cells cooled down and the water level high enough putting cells or packs in water is the cheapest, fastest, and most effective method for the average person.
I think with the home spun battery system. Regular check ups are needed. In Victoria we now need 2hr fire rating on enclosure. One of the first things I did was getting a thermal camera. When I get off my arse and install my system I will be setting up a testing system. Great informative video as always
You should have a vat of some non-corrosive fluid handy to dunk them in like liquid nitrogen, chlorofluorocarbon or diesel. :)
Sorting 18650 cells by (Capacity x Internal Resistance) might be helpful with new builds.
If your BMS is spending a lot of time discharging one or more cell packs, it's an indication that somebody is turning into a Resistor. Smarter BMS?
There is a lot of cells, capacity changes, i think it would be extremly hard to diagnose the problem that way. But then again, putting thermistor on every cell is also not an option, or is it
Funny how nobody else commented on the little faux pas at 9:31 😂
Great series of videos though. Thanks for sharing.
Thanks for watching!
Hey Peter thanks for the excellent information. I think a thermal camera, wire clippers, and an a quick assessable water jar are going to be close by the battery wall from now on.
I think that is a wise choice
Well done for highlighting, an important lesson for anyone thinking of getting into used 18650 cells. It’s no joke, you can’t just build it & use it.
Time for LIFEPO4
yes, when that channel started it might have made sense. but with the price of lifepo4 now, it is a total waste of time and money, not to mention the danger.
Agreed
The only fire proof solution to all off this is to bulid a massive brick furnace and install your diy power wall in it 😁
Or better build a few smaller ones so you dont to have all of your power wall in one.
Benedikt, I agree. It needs to be done regularly and if not well behaved heating occurs, immediate cell replacement is necessary. Treating this without monitoring is like playing Russian roulette. It becomes not a matter of it, but when!
I completely agree with monitoring your batteries, but routine thermal camera reviewing is impractical. Not everyone has them mounted on a wall such that you can see every sell on the camera. I certainly cannot scan mine without pulling individual packs out. The only thing I can say is that it should have been identified by reviewing the Batrium / BMS and seeing a self-discharging battery pack. Also, this really drives home the reasons for NOT NOT NOT using those dumb "active balance" boards...
I think it was a case of compliancy, plain and simple
The phrase....playing with fire comes to mind..........I would not go away on holiday and sleep soundly with this set-up.
I agree ☝️
I had one go thermal on me. I put it in a metal trash can and put a bag of sand over it. Worked perfect! Mine too had a single bad cell. I was lucky I was home at the time. Again, a thermal camera would have allowed me to find the bad cell beforehand and have a better day than what I did.. and would have had a happier wife. The smell was really bad. Cheers Your home was saved!
Thankfully wasn't my home but still a wake up call as to how dangerous these cells can be.
I had a 7s72p 18650 inside the building , unfortunately it got short circuited and burnt the entire electrical room. The bms was of no help. All of this happened on the 30th of December 2020. Ironically the fire extinguisher was inside the room burning.
sucks to hear that buddy, would love to have a chat about it - admin@diypowerwalls.com
why it gets short circuit? pack was cell-fused?
Thanks for the very important video, i am building my solar setup now, but i will start with lead acid. But if/when i transition to lipo i will be adding a DS18B20 temperature sensor in between every 4 cells when building packs, to be able to do continuous temperature monitoring for safety. (i am also in a metal shipping container..) Happy New year ! looking forwards to more videos
I'm thinking that building a few arduinos that have multiple thermal sensors on the packs help detect hot spot and that can open some pack shunts if cells exceed a certain temp might not be a bad addition.
I also still think the fuse wiring was either too thick or the bus bar was acting as a heat sink and allowing it to carry more current than it should have allowed. Do you test your fuse wire attached to a bus bar to see how it works under load with that big copper heatsink to dissipate?
Could wire it to can bus or rs485 with bms, inverter and a gateway like esp32 or stm with WiFi with a piezo electric buzzer and an epo switch and relay for fire system trigger. Lots of options
a 10° difference is massive!
Pete be careful with those packs on the ground. There is some combustibles there.
Need to look at the delta t(temp) over ambient. If 30 is your ambient and it's running 40deg and your ambient in summer is 40 it might run 50. Need more thermal couples on large packs to monitor delta t and or a way to monitor more in the bms to analyze how much extra work some cells are needing and then flagging them for human intervention or monitoring. Or a safety cutoff for potential bad packs or cells
With the cost of LiFePO4 cells being so low these days and them being super safe, is it really worth the risk and time to use old 18650's?
Depends on what you're trying to achieve.
But you've piqued my interest. How cheap? And what country are you in?
Because over here in Aus, batteries/options are pretty slim, postage from the US is BULLSHIT expensive (like they charge the same money in shipping as for the item, if not more).
If there were more/safer options I'd be interested. As it stands though, there aren't any to my knowledge, and we have the second highest power cost in the world.
So, the answer, for some of us, is a resounding YES.
@@jimmyb1451 I am in the UK, Just had a look on Ali-express and there are many cells with free shipping to Australia.
It is cheaper to buy new than have second hand cells delivered to the UK from America.
I think you just need to look around more, i think with the cost of your energy a few extra dollars on decent and safe batteries that will last much longer is a wise move.
Will Prowse is a good source of information about buying new cells from Ali-express.
@@killuazoldyck1352 Personally mate, I'm more about reducing the number of 18650's that get dumped in landfill, or shipped to a third world country for some poor kid to "process".
I'm also happy to do the work required and design the systems to avoid fires. I understand that's not possible for everyone.
Cheers for the info though. I don't use Ali ex.
I'll have a look :)
@@jimmyb1451 "do the work required and design the systems to avoid fires" that is simply not possible, what you can do is to contain the fire and prevent it from spreading!
@@josep.3364 In 98% of the incidents of battery fires, which are already a low probability, it is absolutely possible to avoid the fire.
Or at least to have sufficient warning to remove cells from packs before they turn into bottle rockets.
I have already made suggestions as to what I intend to do when building packs to further mitigate the fire hazard.
All of that aside, the batteries you speak of, present lesser, but still a probability of the same incidences, just over a longer time frame. IE: In reality, there is no risk free solution to the systems we're describing.
Long and short of it, ALL battery systems need maintenance. If I can save some chemicals going into land fill on the way, I'm happy to assume the risks involved and the requisite maintenance. :)
Here is an idea. Now I have left comments before, and I have stated that I am a low voltage virgin, but I have seen a number of ideas in the fifty or so years that I have been in the building trades. One idea that I was impressed with was using fusible links in attic and engineering space fire doors. What the engineers do is make the doors so that they are suspended by a single chain with two pieces of metal somewhere in the chain that are soldered together with low temperature solder. Those two pieces of metal are the fusible link. The doors all had different ratings of course, but the thing worth noting was the fusible link. Would it be worth the time and effort to explore finding out what temperatures of solder are available and using one grade or another of solder to attach the wire fuses to the battery and/or then to the buss bar? I am thinking that this would be more of a backup with that grade of solder at only one end and the wire under a kind of spring load pressure so that it would pop loose at a predetermined temperature.
Internal short started the heat reaction so even if the relevant fuses would have popped, the reaction on shorted batteries would have continued.
if the fuses blew the reaction would stop as the cells were zero volt so no energy left to do anything but to instantly start to cool.
@@HBPowerwall I am sorry but I disagree. Internal short is like putting a nail through the battery. No external fuses can stop that. Those fuses should pop at about 5 amps. Can you tell if any of the fuse wires popped? IMHO the relevant fuses probably popped but the internal short kept on going to cause the fire.
you don't need an internal short, all you need is for the chemical reaction to start, even at 2.5volts there's enough energy in the cell for the chemical reaction to go on, time of the reaction depends on several factors, it can be quite fast.
@@josep.3364 I don't know if an internal short is classified as a chemical reaction and you may be right. Regardless, it was a chain reaction that could not be stopped by blown fuses. Maybe the age of the batteries had something to do with it. One of the most important things you stated is that these batteries have to be monitored and maintained properly, especially if recycled batteries are being used. Thank you for all your work and keeping us up to date with your experiences.
@@dannyperry8070 I think he means that if the shorted cell remains connected, then the other cells in parallel with it would be continuously dumping more energy into it. But once disconnected, the reaction would stop as soon as the energy in the one shorted cell is exhausted.
I do many many battery's for ebikes and never using laptop battery's, minimum is LG MG1 for low power battery's. I hope ppl who watching your films will do battery's on good sort 18650 but not 10 years laptop battery's. Greetings from Poland. Good luck even in new year.
Hi...Relatively new to your channel but I think you raised a really good point. Some hobbies are Ok to skimp on safety as you and your family won't get hurt. Lithium batteries are not that, so perhaps you might do a quick vid on your Thermal camera, cost, are you satisfied with it ? There seems to be a range of prices for Thermal cameras...what's the bare minimum needed for monitoring 18650 batteries do you think?
Time permitting that would be a great idea issue is RUclips doesn't pay the bills. My thermal camera is now i think 3 years old to me and 4 from new..so it's by no means modern but it works I can see issues so that is a win for sure.
The useful working time of a fire extinguisher regardless of its size is around 20 sec.
The fact of two cells failing making me think that while it may have been weak cells, but the cause would have been overcharging or at an C rating that the weak cells couldn't handle.
I had a pack fail on my 40p initial setup, it was one cell that was weak and even with limited current at 0.25C and 4.1v, it tripped the CID. Not long after that the pressure built up enough in other cells and pop pop pop all the cells in the pack tripped the CIDs and broke the circuit. Interesting though none of the cell fusing went. And this was before a BMS, a BMS would have broken the circuit probably after the first CID.
Good video. SERVICE your packs ppl
Always!
A deep concrete box with a removable lid in next doors garden sounds about right .
All cells age & fail that's why the professionals give them a usable life span .
Normal practice is changing out the old bank every 2 years for medical equipment & 4 years for cell towers even if its never been used !
It's because of building the packs with cells of all differant ages and types. Any cell manufacturer will tell you this is a no no. Even though i've done it. And will probably do it again. This is really unfortunate.
I’ve had similar experience and this is why I do not trust recycled Lithium Ion cells. I use LiFePO4 and/or LTO cells for all my projects I don’t want to worry about starting on fire.
Yes this project and packs are awesome don’t get me wrong though. You just can’t trust used 18650s even with testing. Work amazing in my small EV project though.
One LiFePO4 manufacturer has reported ... less than 10 cases ( 9 cases ? ) of fire for every 300,000 LiFePO4 new cells sold. You still need to worry about starting a fire ...
maybe can be useful to use a high power-high pressure cooling fans to get down temp after thermal runaway began and stops disemination?
We would appreciate measurement off this cells @09:16. Capacity, AC inpedance DC resistance.
Its really hard to monitor temp of every cell. Wonder whats the safest thing to do.. heater cells are real issue with age
Not with an IR camera. They can be had for under $200
Like Pete says, if you can’t afford a thermal camera then you shouldn’t be building 18650 packs for home energy storage.
I agree Pete it does seem regular maintenace would have helped alot and a thermal image camera is almost vital these days.
For sure!
Historically, there have been some recalls of laptop battery packs. I don't know about any LG's, but I know some panasonic, sanyo and samsung cells can be defective and at risk of TR.
Is it worth it to risk having a big fire?. Would home insurance cover such an event?. It is already scary to see just one 18650 exploding, I can't imagine a power wall of them catching fire
Each time I’ve seen a fire the overwhelming issue is human. Ie the persons that built the batteries not the batteries them selves. I’m sure there is manufacturing issues but thats probably quite rare. I’ve been lucky so far but price of lifepo4’s are now so competitive you would use these batteries unless you had no other choice.
Nice assessment Pete, thank you for taking the (always more than you think) time out to investigate. Any (access to) Batrium logs?
Thanks buddy, I have a bunch *somewhere, but might pay to reach out to them and explain your plan.
Is the whole power wall concept flawed. Should everyone be building power chimney's.
When using second hand batteries, yes. Second hand batteries may be appropriate for other applications but not for a home powerwall. They cannot be trusted for such an important task.
Flawed in such that they need more maintenance and monitoring. Bms units for larger packs should be built to be able to monitor a whole packs delta t over ambient. And analyze which cells appear to be failing. But with diy or Chinese bms units this isn't always the case and then when using 2nd hand batteries it gets further complicated due to potential uneven dendrite growth. And cell life. Anyone building packs should be factoring all this in and building them in such a way that if they do fail they don't take the house with it. That being said it increases costs and thus most don't. I'd just replace all lipos with lifepo4 or lto cells
Peter, I have a battery made by someone else. Now all are at 0V. I have found one with 3 heaters in it. I need to pull it apart. Plus I have 2 or 3K of batteries tested, which I have done. What are they worth to someone as think of giving up on them?
No idea, i can't give my ones I don't want away
@@HBPowerwall So not worth much at all.
7:21 do some packs put like a thermal strip between the batteries wonder if that's a thing
then it tries to turn itself off
the connection wires to the cells look so thin, I guess that's how it is though looking around interesting
i noticed all power pack are soldered with fuse on them does it mean i cant spot wed the battries am new to this still learning,
Why did they heat solder the cells together instead of using a two-pole current controlled spot welder? Heating a lithium cell directly with a soldering iron is just asking for trouble! The heat from a soldering iron gets transferred to the insides of the cell degrading it, whereas a spot welder only heats the point of contact for an instant and none of that heat (or current) goes into the cell itself. A good spot welder costs less than $100.
Probably because 5 years ago?
if one 18650 gas discharges during welding does it kill the hole 10 batteries in a 10s4p or just the strength of one battery?
That is also why manufactures use thermisitors on their battery packs. You probably have thrown hundreds of them away when tearing packs apart.
And this is why I avoid using mixed used cells and buy modem packs or e bike packs. You know what your dealing with. Un- used Ebike or Schooter packs you have a I idea what your messing with. I just purchased 600 schooter pack cells and they're all within 30mOhm of each other internal resistance and a few 100 mah of capacity. Much easier to harvest and us. Yes you can harvest wild cells. Yes they work. 'o I don't like doing so.
Really don't know that what you're talking about is any safer.
You still don't know how long they've been shelved, in what state,
Agreed, "an idea of what you're dealing with" reduces the probability, but not the possibility nor propensity.
All's I'm saying is, don't be complacent.
absolute awesome video
Thank-You
Just out of curiosity do you have to put any warning signs on the outside of your setup, for the emergency services?
I meet the requirements with signage
So three take aways. A bms capable of somehow taking the bad packs offline and possibly alerting the owner with noise, texts, and emails. Exposed batteries in a platform so all cells can be seen at once with a thermal camera. Ease of thermal verification is extremely important. And finally, fail safe methods to handle unexpected fires even when you aren't there. I'm probably missing a few more takeaways. Perhaps these maintenance issues are why the tesla power walls require internet connections?
an equipped BMS or an dedicated control wifi server module to add into the pack like a balancer. China industry is reading this thread, XD..
No sé si ví bien, pero la celda caliente no es la misma de la de 0 voltios...
I don't know if I saw it right, but the hot cell isn't the same as the 0-volt cell...
The battery packs should really be on quick release pull handles with long blade connection points so you do t have to cut the cable (like the old fashion blade high voltage switches) most don't thing about it until They had there first battery fire and you having to use garden shears to frantically cut the cable (it was lucky had had something to cut the cable)
This is the problem with using cells in packs
They really shouldn't be connected in series and parallel
Each cell should have a bms to bypass the cell temp regulate itself and charge it sos batteries aren't directly connected and the battery should float at its own rates of use have data logs and algorithms sos use it fully
So have many 0v cells and it just cuts them out of the circuit
Cells losing mah but still have life get buck/boost up etc
Peter at around 9:30 the pack to the right if I saw correctly did a fuse went out?
Not quite. When he moved the pack, it shorted across the lead of the power resistor he was using to discharge it.
The lead of the resistor is what fused.
He threw up a vid of it.
@@jimmyb1451 I think you are right so now I presume that the pack stopped discharging. How that Peter will double check if he wants to lower the pack voltage to 0V.
@@rbug4117 Just re-connect the resistor and let it do it's thing until the pack voltage is 0.
Personally, I'd be using a much larger power resistor of much lower resistance to discharge them quicker, but I think that's all that Pete's got available/at hand.
@@rbug4117 ruclips.net/video/4ED_FRcfG2Y/видео.html
Sorry, I'm still confused about what the actual issue/solution was. I see it was some "hot" cells that caused the fire, but how did they get that way? How do we prevent it? Thanks for all your videos.
you can't prevent it, that is how these cell fail usually. Only thing you can do is manage your batteries and check often with a thermal camera to see when the cells just start getting warm - you know then they are going high resistance inside them and will only get worse..
@@HBPowerwall Yikes! Thanks for the reply. I was very excited to start building power walls with 18650 lit ion bats after completing a new scooter bat, but I will need to start looking at LifePO4 cells instead. Too bad they didn't make tons of laptops with these cells! Thank you so much for your videos. They crack me up as well as give me new ideas.
I like the thumbnail but I'm surprised you didn't use the heat camera img instead. Its pretty scary looking
How can you balance batteries that are wired directly in parallel to each other? Kirchhoff says they're always at the same voltage. Why would it matter whether it's 3 cells in parallel or 80.
@@Gearrion But the batteries are all in parallel per pack, not in series. The packs are connected in series to each other, but given their large number of cells each, they shouldn't have significant differences in capacity, and even the more, the closer they should come out. Besides, series capacity difference is solved by active balancing.
Would a BMS have stopped this issue from occurring?
I ordered a thermal camera last week too, just to be a bit safer.
No
At 2:16 you can see the hot cell is the 8th from the left but you say it is the 6th here 3:53?
Learning alot from you thanks for sharing, I notice you're back to fuse wire on bus bar instead of nickel strip how come? what are you considering bailing from? 18650 builds? Cheers Dave edit: sorry just realised this wasn't your pack
I prefer big cells over small cell. The more cells you have the more chances of failure in the future.
Aren't "big" cells just a cluster with a cover of "small" cells?
@@PhreakDarkSoul some are some aren't.
@Repairman ya here too but if you come across them or get rich enough to buy new.
NEVER FUSE THE BATTERIES ON BOTH SIDE! Every fuse has something like 0.1Ω resistance, which together with a used battery's internal resistance, and a fuse on the other side, could be high enough resistance to reduce the current enough that neither of the fuses blow, and you end up with that mess! A single fuse on 1 side only is enough to interrupt the circuit in case of a short!
The fuse's resistance will rise considerably when it heats up, so does the battery's internal resistance!
Fuse blows when the current is high enough to MELT it, so note that the fuse also heats up quite intensely when conducting near it's limit, and since it's directly connected to the battery, will transfer it's heat to the battery.
Cylindrical cells usually have higher thermal resistance on the + side(since + terminal is a cap not the casing), so fuse should be connected to the + side for least heat transfer from the fuse to the cell!
(That being said, I'm not an expert, just a hobbyist, so take it with a grain of salt, but it seems obvious to me.)
Yes i've since read this.. (echoed in comments lol)
Oh man! I want that thermal camera for Christmas...!
I'm looking for an upgrade!! love them so handy
So what I think you just showed is that your fuse wire is too large in diameter. If the fuse wire was thin enough it would have opened on that cell that was zero volts.
Hi Pete, What thermal camera are you using, I am looking at a UTi260B from Banggood but they are not cheep at around $600 NZ. Happy New Year.
Should the fuse wire have blown on the 0v cell?
I don’t think any reasonable person would be offended by your constructive criticisms. Look back at the start of your journey and all the silly mistakes and prejudices you (and Jehu) had.
I wonder if you start buying thermal camera and other safety items monitors, fire extinguisher,metal boxes etc it would be best and cheaper to buy new LeFe batteries?
I got bunches of safety stuffs..
Maybe you should think about using more NTCs or just some DS18B20. That would locate Heater-Cells
LifePo4 will solve that issue..
Also my personal battery has 120 plus temp sensors, Also own a good thermal camera - this wasn't mine it was a subscribers that took things for granted
@@HBPowerwall Are they just NTC's or DS18B20 ?
hello, it has different brand and different mah value batteries. Does anything happen if the volt value is the same mah value different? Finally, what is the danger that the mah value should be different? Do batteries connected in parallel increase the C value?
At time 4:58 you make a comment about not doing 40p. Can you explain that more? Thanks.
your going to have to find a way to add thermistors between all cells with appropriate hardware to monitor for hot spots and automatically cut off all energy going into those cells and ring loud alarms
If you keep adding layers of complexity it becomes less reliable. Placing in a better location would be time better spend i feel
Better safe than sorry!🤔
how much trouble is it to pull that single battery out and replace it? I imagine tearing it down to that cell?
Take a few minutes max when your setup. Two bits of solder, knock the cell out, slide another in re solder... it really takes 3min max (finding it can sometimes take longer!)
@@HBPowerwall ok, then I'm more curious, why don't you pull your heaters out and replace them with good cells?
Every time you mix and match cells from different manufacturers etc. you're increasing the risk factor. You end up with a pack with differing chemistries and composition of the ingredients that make up that cell - which will age differently and have different charge and discharge curves etc. so even though you're 'matching' them (voltage and internal resistance etc) when you put the pack together over time they will deteriorate differently. So my thought is only build packs with the same cells. Why risk it? For small projects like USB power banks maybe not so important - but with large Powerwall style packs - absolutely. Just my thoughts and 2c
I don't disagree - there are lots of reasons to use used cells and indeed different brands and capacity (but not chemistry ) available funds
@@HBPowerwall Absolutely. I've been cobbling together packs for ham radio projects and camping projects for years now and a bunch of Frankenstein packs going strong. Been lucky in the last little while to have access to thousands of Anton Bauer onboard camera batteries (I work as a tech in the movie industry) and been harvesting the cells from them - only recently getting around to building larger packs. I find that one or two cells are bad in the 12 cell pack and the BMS shuts it down. Time consuming but fun to disassemble and test them. Examining the SDS of these cells is a learning experience for sure. Cheers - brilliant videos btw and I've learned a TON from watching you work. Thank you. Saving these cells from recycling is cathartic for me ;)