Yes, the fireball is larger with higher state of charge.Only as it relates to resistance.
I'm thinking more about how long will the cell discharge given a short.
The 40% is for battery lifetime mostly.
Yes, the fireball is larger with higher state of charge.Only as it relates to resistance.
I'm thinking more about how long will the cell discharge given a short.
speaking from experience... The F'ng fireball is big enough regardless of 40% or 90% and still stinks and causes damage...Yes, the fireball is larger with higher state of charge.
The 40% is for battery lifetime mostly.
Is the fireball larger, or does it last longer? From what I understand, the reaction in the battery can only go so fast so it was my understanding that the fireball would just last longer, not be more intense.Yes, the fireball is larger with higher state of charge.
The 40% is for battery lifetime mostly.
Yeah nope… cannot argue….i hear that if it's over 0% it can catch on fire ? and be annoying to clean up ?
Both. I was just reading a paper on LTO safety today. Different states of charge create varying proportions of volatile materials because of the way they are altered by moving ions. The cells include vinyl esters, etc. to help control dendrite formation and other life-reducing reactions.Is the fireball larger, or does it last longer? From what I understand, the reaction in the battery can only go so fast so it was my understanding that the fireball would just last longer, not be more intense.
LTO is capable of a lot higher discharge rates than LiFePO4 under normal conditions so I would assume they would discharge at a higher rate in a dead short as well, no?Both. I was just reading a paper on LTO safety today. Different states of charge create varying proportions of volatile materials because of the way they are altered by moving ions. The cells include vinyl esters, etc. to help control dendrite formation and other life-reducing reactions.
Basically, the chemistry changes a lot with state of charge, and all that stored energy ends up as a bigger, badder, longer lasting fireball.
What are you talking about?You guys aren’t helping your case.
I have not looked at a comparison, but since LiFePO4 actually has a higher energy density I would expect similar results. Things change once the reaction is allowed to go exothermic, but the key point is that the amount of energy in the cell is actually higher at higher SOC. That energy will get expended somehow, and "discharge rate" is no longer a viable term in the usual sense.LTO is capable of a lot higher discharge rates than LiFePO4 under normal conditions so I would assume they would discharge at a higher rate in a dead short as well, no?
When I received my 16 cells, I 'batched' them based on the test results I received from vendor. I sorted them based on their stats (mostly capacity, but considered IR as well) and labeled each battery by group. I built them into 4 12v packs. I currently am running two packs in parallel, and recent check shows all cells in each pack within .002v of each other, and the two packs are within .005v of each other. Of course, I top balanced myself. In the future, I may convert them to 48v, but right now, I have a really nice 12v inverter that I don't want to replace, and my system needs to remain movable. It moves several times a year, and I need to be able to lift and carry each component, as I am usually not on a smooth surface. I cannot lift a 48v 280ah battery:/interesting, thank you for sharing
this motivates me to uniquely label each cell, it only takes one moment for me to grab the wrong one when they all look the same
Since you havent mentioned this again I assume it was just a passing thought.No - I know I know- f’ng rookie why the f did you not….
Considering the outside of the packs are all negative, even if over duration they wore out…
Honestly I am going over the whole system and building out for robustness.
I have a Simarine Pico system to monitor.
I will be going with 4 batteries- 4 cells each with 150A BMS and balance board on each battery and a Simarine Shunt with TS.
The Simarine solution has an ability to trip a relay (call into factory) and can trigger an alarm if a Temp sensor goes high.
Also going to build compression plates with FR4 pads to hold the batteries in place, locked.
This is all going to be in a box under the van where I will build an ejection solution to eject the pack if it decides to behave badly
Me thinks cylindrical vs prismatic doesn't matter as far as "dangerous" as much as the chemistry does. Are you saying you have DIY LiFePO4 packs now? Or are they the more common 18650 NMC/LCO/NCA cells? LiFePO4 cells don't have a real risk of thermal runaway. The others have a very high risk.So far looks like prismatic DIY packs have caused several accidents and are quite dangerous. I wonder if cylindrical cells build had such accident. I have DIY cylindrical packs power wall at home and plan to use same for van when I have need.
Not necessarily. Prismatics are the cheapest and easiest to source. Which makes them the most commonly used by beginners who make dangerous errors. I would imagine that building these batteries would be so easy now that we have BMS (not long ago, I ran without BMS, as did many others). But then I see a picture of improperly sized conductors, rats nest of wires and bad crimp connections. Stuffed into a high vibration RV storage cabinet.So far looks like prismatic DIY packs have caused several accidents and are quite dangerous. I wonder if cylindrical cells build had such accident. I have DIY cylindrical packs power wall at home and plan to use same for van when I have need.
Mine is lifepo4 32650 prebuilt packs so it’s easier than raw prismatic cells pack.Me thinks cylindrical vs prismatic doesn't matter as far as "dangerous" as much as the chemistry does. Are you saying you have DIY LiFePO4 packs now? Or are they the more common 18650 NMC/LCO/NCA cells? LiFePO4 cells don't have a real risk of thermal runaway. The others have a very high risk.
They can still cause a fire if improperly connected to your system. The battery is not the problem usually. It's the connections, size of conductor that supply it, size of OCPD etc.Those new LiFePo4 blades claim to be very, very safe, even in puncture test. I'd love to get some of those and slip them behind the wall panels in my van. ?
I agree. When it comes to the energy storage side of any system, this is not the time to be cheap.They can still cause a fire if improperly connected to your system. The battery is not the problem usually. It's the connections, size of conductor supply it, size of OCPD etc.
@TorqueMonster72I agree. When it comes to the energy storage side of any system, this is not the time to be cheap.