LTO battery fire

[SamDeleted]

Today I've learned.....

When you share a helpful post on this forum, you get:
- accused of using 'hap hazard methods'
- told to "revisit basics & safety methods"
- accused of "disrespect"
- attacked with bogus appeals to authority

Please ignore anyone on this forum who is so smart that they can't have a battery fire, or too proud to admit when they do.

Peace

"Accused...". it seems some feelings have been hurt by the replies ?....

I am still a little confused here, maybe you can explain... Who exactly was your original post meant to help? And how ? I don't see how you detailing your fantastic firefighting skills is much use to anyone? Not sure..... if you were hoping we would all say nice the about you putting out that fire ... HA. not likely. (especially considering it's your negligence that caused the fire in the first place!)



also another question if you don't mind please...., who else lives in the house you nearly burnt down? are there women & children? Or elderly? Who exactly are you putting at risk ?

 

[SamDeleted]

The funny thing about this forum. You will get critique, some of which is good for your ego and that’s not, most of which is well deserved. This is a learning location, learn to suck it up, get a thicker skin and use the advice you deem appropriate. Or don’t expose yourself by posting.

Well said. Cowboy up ?

 

[SamDeleted]

But telling a complete stranger "Time to revisit basics" is polite?

Depends, did they just nearly burn their house down?


I think it's impolite not to !

 

[Steve_S]

I was maybe a tad harsh to the OP and for that I do apologize, I know he was having a Bad Day but the flip side no harm came to anyone which is the Most Important thing right. He doesn't know any of us, our experience(s) or our backgrounds and that's ok too, AND I totally understand his reaction to my post, hell I may have reacted similarly if someone made a comment like I did, when sitting there staring at a major mess. Some here KNOW that I can get "snarky" when certain things happen, we are all capable of it, I've been tapped on the shoulder by a couple of mods over the years LOL.

Let's just focus on helping this fellow out and getting it sorted. I will exist this as requested and as I feel that any of my input would serve no further purpose in this thread. One thing to keep in mind, many if not most of us have had "disasters" of one sort or another and that experience is invaluable.

FYI: The "crap" the Fire Extinguisher blew all over everything is NOT HEALTHY AT ALL ! You need to carefully clean that up wearing face masks & gloves + protective clothing (disposable) is best. It is horribly insidious and can have very serious health effects.

Good Luck on your future projects.

 

[SamDeleted]

I was maybe a tad harsh to the OP and for that I do apologize, I know he was having a Bad Day but the flip side no harm came to anyone which is the Most Important thing right. He doesn't know any of us, our experience(s) or our backgrounds and that's ok too, AND I totally understand his reaction to my post, hell I may have reacted similarly if someone made a comment like I did, when sitting there staring at a major mess. Some here KNOW that I can get "snarky" when certain things happen, we are all capable of it, I've been tapped on the shoulder by a couple of mods over the years LOL.

Let's just focus on helping this fellow out and getting it sorted. I will exist this as requested and as I feel that any of my input would serve no further purpose in this thread. One thing to keep in mind, many if not most of us have had "disasters" of one sort or another and that experience is invaluable.

FYI: The "crap" the Fire Extinguisher blew all over everything is NOT HEALTHY AT ALL ! You need to carefully clean that up wearing face masks & gloves + protective clothing (disposable) is best. It is horribly insidious and can have very serious health effects.

Good Luck on your future projects.

Steve, you're a nicer man than I .

 

[42OhmsPA]

The busses on the OP’s are open ended not a closed slot like your flexible buss bar. I’d be hesitant to drill&tap a hole in those because it hard to tell where the resistance welded area of the laminated copper ends. It’s been done before with success but I don’t think the risk to reward is worth it. If anything I’d try to use a crimp terminal for the balance lead that has the widest surface area eyelet for a 6mm-1/4”
hole. There are those that don’t want anything between the TOP of the buss and balance terminal but I’ve used a washer there without any issues.(Not between the terminal and buss!) The biggest problem that I’ve seen with balance leads is a poor crimp. For some reason those little things can be pitha to crush.
Those slots on those flexible buss are my pet peeve, however I have not heard of any failures( if so let me know). Just check the torque and don’t worry about it. That looks like a tube of Ox-Gard. While this and Noalox are great for power panel junctions. I’ve found etched, discolored surfaces on tinned lugs and nickel plated buss after being in use a while then disassembled. This leads me to thinking that something’s happening that shouldn’t.(no resistance or voltage difference measured) I’ve switched No-ox-Id A special and have not seen any issues.

Thanks for the detailed reply. Good eye on the GB OG, I haven't seen any issues after ~ 1 year when I disassembled but I'd rather be extra safe long term.

NO-OX-ID Two 2-Ounce Tubs A-Special Electrical Contact Grease - Improves Conductivity and Fights Corrosion in Automotive Marine Industrial Maintenance Antenna and Railroad Applications https://a.co/d/dfBzPBT
I'll order that, the brushes will be nice and it should last me the next decade.

 

[Nobodybusiness]

You’ve had your fair share of bad luck in balancers ?
The only problem I ever had with a balancer is one Heltec 4s had a capacitor installed backwards! No, I didn’t use it.

It’s that way with everything for me.

I must have been a right bastard in my previous life.

 

[Nobodybusiness]

I've discovered that my active balancers make my battery worse than when it's left on its own with an occasional passive balance via Batrium.

They are individual units, and I'm pretty sure their voltage measurement error forces a 0.04V drift in my cell voltages. They'll seek that dV after about a week following a Batrium 0mV balance. When I leave them off, it takes about a month before my Batrium needs to be fired up for a few Ah of burning. Batrium cell voltages are within ±.005V of my Fluke. I have no idea what the balancers are measuring.

I like Batrium.

I was going to use it exclusively but then found out after buying a ton of K9s that they don’t have individual battery termination if there is a problem.

It will only run one shunt breaker and I have too many batteries for that.

 

[Bluedog225]

"Time to revisit basics"

Couldn’t be more gentle.

 

[Skypower]

It’s that way with everything for me.

I must have been a right bastard in my previous life.

Lol, you’re not alone. Most of the time I’ve got Mr Murphy’s Law riding on my shoulder. One of my mantras; Just because someone else’s can get away with doing something that way, doesn’t mean I can, because Murphy’s Law will find me.

 

[OffGridForGood]

From the picture and description - this could have ended very bad.

My home build LTO battery had a fire last night.

Interesting to see LTO - from what I have seen these cells are expensive compared to LFP - why use them for stationary set up? just learning experience or was there some specific reason to use these cells? IIRC the LTO voltage curve is basically 1.5 to 2.6v so a 22s will run 33v to 57v.
I don't know what inverter can operate in this wide range, makes me wonder what the current would be doing as the voltage drops below 48v.

We heard a large pop and came out to find a small arc fire in one of the cells. One of the cells had popped completly apart. The wiring was arcing and causing a small flame.

If you had not hear the pop, we may not have seen this posting...
Imagine if the pop happened while you were asleep, or just out of the house for a few hours.

We were running five 10 amp active balancers on five 22S banks.

10 amp active balancers: Did the cells require 10-Amp active balancers to stay in balance?
is this a normal requirement for LTO?

Either:
- the balancer died
- a cell went bad, or
- the wiring became corroded and high current.

Any insight since the event to indicate the cause of the fire? is there data available from your monitoring system to indicate if a cell went into over-voltage without the BMS cutting it off? What BMS(s) are you using for the 22s?

I post this to remind people that we need a mechanism to detect these events and shut everything off and alert you to the problem.

Good - glad you did. Now follow through:
Safety starts with following best practices in the original set up. If you think your set up is being judged harshly - you are not seeing the hazards we see, and you should re-evaluate.
I like to play with test set-ups on my workbench and try out new ideas. Sometimes I cobble together some parts and run a test under direct supervision. Then I disconnect it when I leave the work area. Non-permanent test set ups should not be left unattended, after all we are testing, we need to be present. Permanent systems need to be built to operate without supervision.
Clearly the original set up is not a model of safe battery practices, and wheather pointed out by members here or not does not alter the facts. We would be remiss to Not point out the hazards, 10's of thousands of others will see a posting on the forum, many of those viewers will not realize the hazards without this being pointed out.

I think this post should be moved to "up-in-smoke, learn from my mistake".

 

[Skypower]

Thanks for the detailed reply. Good eye on the GB OG, I haven't seen any issues after ~ 1 year when I disassembled but I'd rather be extra safe long term.

NO-OX-ID Two 2-Ounce Tubs A-Special Electrical Contact Grease - Improves Conductivity and Fights Corrosion in Automotive Marine Industrial Maintenance Antenna and Railroad Applications https://a.co/d/dfBzPBT
I'll order that, the brushes will be nice and it should last me the next decade.

A couple things; the NO-OX-ID A doesn’t spread well when cold so keep it in a warmer place till use. Use paper towel to lightly pull the brush stands to remove any potentially loose strands or contaminants. They actually supply a high quality acid bush and haven’t seen any loose strands. Keep the exposure to open tub, brush and parts treated to a minimum. Cap them and finish the assembly asap to minimize any contamination. A spec of contaminants or a brush strand defeats the purpose. I store the brush in a ziplock.
If you haven’t seen an issue in a year then I wouldn’t be too worried and unless you’re redoing something I’d just leave it alone. Any time you mess with something there’s always a risk to gain.

 

[rhino]

Crocodile clip - Wikipedia

en.wikipedia.org

A crocodile clip or alligator clip[1] is a plier-like spring-tensioned metal clip with elongated, serrated jaws that is used for creating a temporary electrical connection.

 

[Sanwizard]

FYI your fire was not put out with a co2 fire extinguisher what you used was a dry chemical charged with nitrogen gas which leaves a very corrosive substance which will destroy your electrical and electronics components that fine yellowish white powder will react with moisture in the air

anything in the area that was exposed to the dust can become damaged due to corrosion

I would recommend buying a co2 extinguisher because no residue and it also cools the fire and removes oxygen
there is no way I would set a dry chem extinguisher off in my solar shed

@rodrick, can I ask which CO2 extinguisher you use? I am shopping around for black friday deals on CO2 extinguishers, but I am finding most are in the $400 to $500 dollar range.

 

[Nobodybusiness]

Lol, you’re not alone. Most of the time I’ve got Mr Murphy’s Law riding on my shoulder. One of my mantras; Just because someone else’s can get away with doing something that way, doesn’t mean I can, because Murphy’s Law will find me.

I hear ya. Sounds like we have similar problem.

 

[Skypower]

From the picture and description - this could have ended very bad.

Interesting to see LTO - from what I have seen these cells are expensive compared to LFP - why use them for stationary set up? just learning experience or was there some specific reason to use these cells? IIRC the LTO voltage curve is basically 1.5 to 2.6v so a 22s will run 33v to 57v.
I don't know what inverter can operate in this wide range, makes me wonder what the current would be doing as the voltage drops below 48v.

If you had not hear the pop, we may not have seen this posting...
Imagine if the pop happened while you were asleep, or just out of the house for a few hours.

10 amp active balancers: Did the cells require 10-Amp active balancers to stay in balance?
is this a normal requirement for LTO?

Any insight since the event to indicate the cause of the fire? is there data available from your monitoring system to indicate if a cell went into over-voltage without the BMS cutting it off? What BMS(s) are you using for the 22s?

Good - glad you did. Now follow through:
Safety starts with following best practices in the original set up. If you think your set up is being judged harshly - you are not seeing the hazards we see, and you should re-evaluate.
I like to play with test set-ups on my workbench and try out new ideas. Sometimes I cobble together some parts and run a test under direct supervision. Then I disconnect it when I leave the work area. Non-permanent test set ups should not be left unattended, after all we are testing, we need to be present. Permanent systems need to be built to operate without supervision.
Clearly the original set up is not a model of safe battery practices, and wheather pointed out by members here or not does not alter the facts. We would be remiss to Not point out the hazards, 10's of thousands of others will see a posting on the forum, many of those viewers will not realize the hazards without this being pointed out.

I think this post should be moved to "up-in-smoke, learn from my mistake".

The main place I see a lot of use for LTO is high performance automotive audio. They like the punch of the high discharge that these offers. I’ve seen some without any balancers employed and have no idea if that’s acceptable or wise for this chemistry. From what I’ve gathered LTO has an extremely high cycle life and stable chemistry. The round trip efficiency is what I’d like to know. I’ve noticed throughout the forum where an unbalanced battery is considered, a bad connection/loose terminal is a likely culprit and no amount of balance current can fix it. If the OP had need of a lot of balance current I’d be wondering.

I’m so glad his whole house didn’t go up. He could probably just make some corrections, replace the blown cell and the two adjacent cells then be back in business. I’d be watching it like a hawk for balance, heat and remove anything flammable in the vicinity.

 

[Skypower]

@rodrick, can I ask which CO2 extinguisher you use? I am shopping around for black friday deals on CO2 extinguishers, but I am finding most are in the $400 to $500 dollar range.

Yeah I was just looking too. I’ve got a new ABC on an opposite wall but I like the Co2 idea. Seen some five pounders on Amazon for $204.

 

[JJJJ]

Regardless of the chemistry used it is a good reminder to review the basics. Good for us all:

1. Ensure proper connections, recheck as needed.
2. Include adequate fuses and breakers
3. Make sure wire size and capacities are above the required or expected loads
4. Consider a technical review by other members prior to going live with the installation. It is amazing the number of "small" things others saw with my build that can really add up (in a bad way)

Periodically look over your system with a critical eye. Especially if in a mobile application.

If your design is experimental, perhaps considering a location outside the home? Each person needs to make their own choice on this. Just a thought.

I have driven a car for many many years. Even with this vast experience it still pays to follow certain safety procedures when getting behind the wheel. Even the most experienced person takes a chance if they skip basic safety considerations.

 

[OffGridForGood]

The main place I see a lot of use for LTO is high performance automotive audio. They like the punch of the high discharge that these offers.

I am an auto buff - by other addiction er hobby, and on the car forums I have seen quite a lot of chat about LTO - from Honda Plug-in hybrids IIRC. They have often talked about doing a manual balance a few times per year "if needed" or checking the balance every few months. This was why I asked the OP if they 'needed' 10-amp balance - since it didn't seem to add up with what I have read over the last few years in the automotive area.

I’ve seen some without any balancers employed and have no idea if that’s acceptable or wise for this chemistry. From what I’ve gathered LTO has an extremely high cycle life and stable chemistry. The round trip efficiency is what I’d like to know. I’ve noticed throughout the forum where an unbalanced battery is considered, a bad connection/loose terminal is a likely culprit and no amount of balance current can fix it. If the OP had need of a lot of balance current I’d be wondering.

agree.

I’m so glad his whole house didn’t go up. He could probably just make some corrections, replace the blown cell and the two adjacent cells then be back in business. I’d be watching it like a hawk for balance, heat and remove anything flammable in the vicinity.

Some proper connections, bus bars and cases would be a great start. He said five packs - so this was not some spur of the moment set up, just to test an idea for a few days, this was a build. Hope he comes back and learns something from the more experienced among the forum.

I have to wonder if the voltage range for those LTP allowed his current to climb as the voltage dropped down lower and lower, I can imagine from the comments about "pushing the system to the limit" could mean the voltage dropped to sub-48v and the amperage climbed to maintain the power output increasing heating at a poor connection leading to the arc and cell exploding. Too bad there wasn't a camera set up to record the whole event, we could have seen what happened. I should put a cheap aftermarket dash-cam in my solar room, to watch and record in a loop what is going on in there!
If as you say, if he replaces the blown cell, what are the other changes this set up needs to be safe(er):
Proper bus bars and cell holders,
proper sensor wires and ring terminals for the BMS leads,
metal cases for each pack,
Heat and smoke detectors in the vacinity - alarm in the house and link to his phone,
some relays to allow remote disconnect of the ESS ?

I would be interested to know what the rest of the system set up looks like, and what loads are being applied.

 

[TomC4306]

But telling a complete stranger "Time to revisit basics" is polite?

Based on what we can clearly SEE in YOUR photo?
Yes