I understand the sentiment, but with regard to "So do the best you can, and enjoy!" , the participation trophy can be a burned down structure the risk for which should be mitigated to the maximum extent practical not to the "best of one's abilities".And a tornado may carry your home away. You can never protect against everything, so just use common sense and best practices, and you should be OK. There is a thread in here where someone's cabin burnt down via a faulty commercially made battery. Tesla and Nissans and BMW EV's catch fire, and they are not DIY. So do the best you can, and enjoy!
Of course. But with DIY, if you do not know what you are doing, you can kill yourself, or burn your house down. You are also at risk with skydiving, driving, walking across the street, not wearing a mask, and pulling on supermans cape. No trophies either.I understand the sentiment, but with regard to "So do the best you can, and enjoy!" , the participation trophy can be a burned down structure the risk for which should be mitigated to the maximum extent practical not to the "best of one's abilities".
The difficulty I'm having with your statements is that you are treating "assumed risk" as a "roll of the dice". Once you have quantified risks and mitigated those as appropriate for the application you have a sound approach to risk management with an educated level of assumed risk.Of course. But with DIY, if you do not know what you are doing, you can kill yourself, or burn your house down. You are also at risk with skydiving, driving, walking across the street, not wearing a mask, and pulling on supermans cape. No trophies either.
I agree with everything you just said.The difficulty I'm having with your statements is that you are treating "assumed risk" as a "roll of the dice". Once you have quantified risks and mitigated those as appropriate for the application you have a sound approach to risk management with an educated level of assumed risk.
If you don't know what you are doing, you have no real knowledge of the "assumed risk" and so this "roll of the dice" is more likely to be a "predictable outcome" rather than random.
At the very least people need to know what their assumed risks are and one way is to establish some best practices so they understand these issues.
It won't make a bean's worth of difference.The difficulty I'm having with your statements is that you are treating "assumed risk" as a "roll of the dice". Once you have quantified risks and mitigated those as appropriate for the application you have a sound approach to risk management with an educated level of assumed risk.
If you don't know what you are doing, you have no real knowledge of the "assumed risk" and so this "roll of the dice" is more likely to be a "predictable outcome" rather than random.
At the very least people need to know what their assumed risks are and one way is to establish some best practices so they understand these issues.
And can dendritic growth failure result in a true internal short (meaning high-enough internal current to generate enough heat to bloat neighboring cells and/or cause a fire?A good example is end of life failure (not often talked about on this forum)
The most common end of life failure i’ve seen is dendritic growth failure, it results in the cell internal shorting and in the hundreds of LiFePO4 cells i have seen with this failure mode it has resulted in LVD disconnect of the pack, and one dead cell.
Yes, that’s the right question - has anyone experienced sudden and extreme cell failure sufficient to generate enough heat to affect adjacent cells before the BMS reaches LVD?Has anyone experienced LiFePO4 dendrite failure causing damage to adjacent cells in a properly BMS protected pack?
Well. I was turned into a Newt but I got betterThere are also people with insufficient knowledge to be doing this type of DIY ... but is rare that they are harmed other than financially.
So .... now we understand your forum name. LOLWell. I was turned into a Newt but I got better
This is very valuable information that would be wonderful to consolidate into some kind of accessible knowledge base.A good example is end of life failure (not often talked about on this forum)
The most common end of life failure i’ve seen is dendritic growth failure, it results in the cell internal shorting and in the hundreds of LiFePO4 cells i have seen with this failure mode it has resulted in LVD disconnect of the pack, and one dead cell.
Has anyone experienced LiFePO4 dendrite failure causing damage to adjacent cells in a properly BMS protected pack?
There have been at least two fires.From watching this forums, it seems like the most common risk is in ruining your cells .... or maybe things just not working like you wanted or expected.
There is a potential for causing a short with a tool which has a potential for significant harm.
With the exception of this thread, I haven't seen major things happening which pose a huge risk .... and anyone who claims to know what the cause of the fire this thread is about .... is just blowing smoke ... pun intended.
There are also people with insufficient knowledge to be doing this type of DIY ... but is rare that they are harmed other than financially.
I like the idea in general but don't think pressure specifically is going to be very fruitful. You are speaking about the realm of "diagnostics and prognostics" a general treatment of which for cell array LiFePo is beyond most people's technological sophistication.I’ve basically convinced myself to add a pressure sensor to my 300kgf clamping fixture and have started a new thread on the subject: https://diysolarforum.com/threads/monitoring-pack-pressure-for-safety.28997/
Pack-level pressure is so easy to add and monitor, I’m going to start with that.
May look into cell-level temperature monitoring as well but starting with pressure seems like the best place to start since knowing how close my 300kgf fixture is to 300kgf will be worthwhile all on it’s own…
If anyone has any ideas for what’s best to do with an early warning if a possible combustion event, I would appreciate contributions in that thread…
This is very valuable information that would be wonderful to consolidate into some kind of accessible knowledge base.
I assume you are speaking of series cell battery configurations? How many of these had paralleled series batteries?
Fantastic info - thanks!If you use a BMS such as a Batrium, there is a temperature sensor on each cell. You can program disconnect for a temperature value if you want.
If you use a BMS such as a Batrium, there is a temperature sensor on each cell. You can program disconnect for a temperature value if you want.
So this is probably a low probability event for solar applications.The dendrites are tiny, and the internal shorts were small enough that discharge wasn’t catastrophic. Basically the cell (and it’s parallel partner) were destroyed, but the other cells in the series pack were OK.
This was caused by high current charging at high temperature, and cell life in some cases was less than a year.
No argument there…I'm sorry to question your statement but I can't find an example of a correctly designed and built Lifepo4 battery causing a fire. In every case I have read about there is a serious mistake involved. Applying force to the terminals and creating an internal short is a big mistake.
I’m not sure if you are saying fhorst’s fire was caused by this mistake or not - I thought her cells were on wood?Placing a set of cells that have a positively charged external metal case with inadequate insulation on a grounded metal floor of the battery enclosure is a serious mistake.
fhorst makes the point early-on that the connections we make to these cells is nothing like the connections they were designed for.I keep reading about these heat discharge events but I have yet to see one that wouldn't be prevented by following commonsense protocols.