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you need a precharge circuit for them to charge the inverter, otherwise the contacts wear out quicklyThese finally showed up today fun to play with for a cheap price
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you need a precharge circuit for them to charge the inverter, otherwise the contacts wear out quicklyThese finally showed up today fun to play with for a cheap price
It's important to note that isn't even the regular JK BMS everyone uses...Around the 2:40 mark he talks about JK BMS being a failure… and how they are over charging because reset…after few days being off.
Hmmmmm… What now?
Presumably you've also taken a look at Stuart Pittaway's DIY BMS?Part of me (and I've said this before) wants to build the BMS as an Open Source version. It's not even that hard, and I already have several improvements in mind, but I just don't have the time (or energy to be honest). I've got so many other projects ongoing...
Presumably you've also taken a look at Stuart Pittaway's DIY BMS?
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Faulty installations often to blame for battery fires
The Electric Power Research Institute (EPRI), the US Department of Energy's Pacific Northwest National Laboratory (PNNL), and German battery analysis specialist Twaice have jointly evaluated 26 battery fires between 2018 and 2023. They say that the diversity of components plays a critical role...www.pv-magazine.com
Many of the new rules being proposed in both the EU and by the fire prevention agencies are limiting home storage to 20 kW have to be outside not near a window, all kinds of restrictions. Pretty much if it's not in a self-contained box or something it could be yanked off the wall away from the home. They're not going to like it.I just read that and it doesn't seem to make sense or add anything useful... Is it just me or has the quality of editors vanished in recent times?
"EPRI said that that damages are more likely caused by system components outside of the cells and control systems. It said that the complexity of coordinating numerous components might cause fires.
The group said that failures will also occur when the range of components continues to increase. They identified the operation of storage systems as the second-most common source of errors. Most control systems are the reason for failures, especially state-of-charge limits in systems."
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Prob could be more clearly written but seems like it's saying:I just read that and it doesn't seem to make sense or add anything useful... Is it just me or has the quality of editors vanished in recent times?
"EPRI said that that damages are more likely caused by system components outside of the cells and control systems. It said that the complexity of coordinating numerous components might cause fires.
The group said that failures will also occur when the range of components continues to increase. They identified the operation of storage systems as the second-most common source of errors. Most control systems are the reason for failures, especially state-of-charge limits in systems."
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Very small numbers in the scheme of things."US-based EPRI has set up a database listing battery storage fires throughout the world. It recorded 50 incidents during the 2018-23 period. "
I wonder how many cooking fires or cars and garage fires or my bonfire got out of control fires etc there have been in the same timeframe ? How about the diesel car that burned the whole car park down at one of the UK airports.
So it seems like a single 105Ah cell can generate over 40 liters of hydrogen.Interesting reading. Thermal runaway and gasses released by lfp cells
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Simulation of Dispersion and Explosion Characteristics of LiFePO4 Lithium-Ion Battery Thermal Runaway Gases
In recent years, as the installed scale of battery energy storage systems (BESS) continues to expand, energy storage system safety incidents have been a fast-growing trend, sparking widespread concern from all walks of life. During the thermal runaway ...www.ncbi.nlm.nih.gov
The summary at the end
In this paper, the analysis of the gas component of the battery heat of the LFP was carried out, the simulation model was established in FLACS software, and the law of diffusion of the gas and the explosion of the gas in the storage battery cabin were studied by establishing the diffusion–explosion model.
(1)
Without considering the electrolyte vapor and smoke, the explosion limit of the mixed combustible gas is 4.86–52.2%. When the TR occurs in the middle of the 48 batteries in the prefabricated chamber, the shortest time for the concentration of combustible gas to reach the explosion limit is 9.8 s.
(2)
The maximum explosion overpressure caused by the explosion of combustible gas generated by the TR of 24 and 48 batteries in the middle of the prefabricated cabin is 92.2 and 566 kPa. Compared with the upper left corner and lower right corner, the TR of the battery in the middle of the prefabricated chamber is the least likely to cause serious harm.
(3)
When the combustible gas produced by the TR of 24 batteries explodes at different locations in the prefabricated cabin, the maximum explosive overpressure generated at 5 m outside the prefabricated cabin door is 2.2 kPa, which does not pose a threat to the human body. However, when 48 batteries are thermally out of control, the maximum explosive overpressure can reach 45.7 kPa, which will cause serious harm to the human body.
Long post - sorry.Interesting reading. Thermal runaway and gasses released by lfp cells
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Simulation of Dispersion and Explosion Characteristics of LiFePO4 Lithium-Ion Battery Thermal Runaway Gases
In recent years, as the installed scale of battery energy storage systems (BESS) continues to expand, energy storage system safety incidents have been a fast-growing trend, sparking widespread concern from all walks of life. During the thermal runaway ...www.ncbi.nlm.nih.gov
The summary at the end
In this paper, the analysis of the gas component of the battery heat of the LFP was carried out, the simulation model was established in FLACS software, and the law of diffusion of the gas and the explosion of the gas in the storage battery cabin were studied by establishing the diffusion–explosion model.
(1)
Without considering the electrolyte vapor and smoke, the explosion limit of the mixed combustible gas is 4.86–52.2%. When the TR occurs in the middle of the 48 batteries in the prefabricated chamber, the shortest time for the concentration of combustible gas to reach the explosion limit is 9.8 s.
(2)
The maximum explosion overpressure caused by the explosion of combustible gas generated by the TR of 24 and 48 batteries in the middle of the prefabricated cabin is 92.2 and 566 kPa. Compared with the upper left corner and lower right corner, the TR of the battery in the middle of the prefabricated chamber is the least likely to cause serious harm.
(3)
When the combustible gas produced by the TR of 24 batteries explodes at different locations in the prefabricated cabin, the maximum explosive overpressure generated at 5 m outside the prefabricated cabin door is 2.2 kPa, which does not pose a threat to the human body. However, when 48 batteries are thermally out of control, the maximum explosive overpressure can reach 45.7 kPa, which will cause serious harm to the human body.
electricity isnt safe too. many people have diedWe have been told “LIFEPO is safe”. Over and over. We are dealing with stored energy. Now the question is compared to what for safe.?
The Tesla mega packs have passive venting and a thermal roof to deal with the small chance of thermal runaway, and many safety features which we just don't see in the vast majority of diy configuration, or even in one of the walk in type ess containers using rack mounts. Protection/isolation at the module level, multiple layers of redundancy.Do lead-acid batteries outgas and create an explosive atmosphere when damaged or shorted? Or only during charging, as current is put in?
Seems to me those cargo container ESS could be much more explosion resistant if LiFePO4 cells were sealed in metal boxes, filled with nitrogen, plumbed to external vent with a rupture disk.
has there been any mishap with these giant stored capacity ?The Tesla mega packs have passive venting and a thermal roof to deal with the small chance of thermal runaway, and many safety features which we just don't see in the vast majority of diy configuration, or even in one of the walk in type ess containers using rack mounts. Protection/isolation at the module level, multiple layers of redundancy.
View attachment 216978
There was an event that caused one of the mega packs to go up in flames during the commissioning process at the geelong big battery in Australia. The resulting fire caught a neighboring mega pack on fire.has there been any mishap with these giant stored capacity ?
See https://diysolarforum.com/threads/house-burned-down.83098/post-1077834I have seen that you showed a black mega fuse I guess from Victron.
AZ fire- The battery modules contained 28 Li-ion battery cells (14 series, 2 parallel) of Nickel Manganese Cobalt (NMC) chemistry and a module-level BMS. The 14 battery modules were connected in series, which provided a per-rack nominal voltage of 721 V. The LG Chem batteries in the McMicken BESS were NMC, with an energy density greater than 200 Wh/kg.They are a leader in everything they do.
Looks like the current mega pack 2 uses 156Ah LFP prismatic cells from CATL:AZ fire- The battery modules contained 28 Li-ion battery cells (14 series, 2 parallel) of Nickel Manganese Cobalt (NMC) chemistry and a module-level BMS. The 14 battery modules were connected in series, which provided a per-rack nominal voltage of 721 V. The LG Chem batteries in the McMicken BESS were NMC, with an energy density greater than 200 Wh/kg.
Moss Landing BESS- The Moss Landing BESS phase one comprises a 300MW modular, fully integrated, pad-mounted lithium-ion battery energy storage system capable of holding 1,200MWh of electricity. The batteries were supplied by LG Energy Solution and have a discharge duration of four hours.
Moss Landing is comprised of Tesla Megapacks. I've looked to see what cells are used in the Megapack but no clear answer.