FilterGuy
Solar Engineering Consultant - EG4 and Consumers
After reading the first post my reaction was. "Interesting, I wonder if the system caused the fire?"
When people started immediately blaming the cells my reaction was "but we don't know that!"
Then the eagle eyes of the forum members identified a lot of questionable things:
1) No BMS
2) Wrong bus-bars on the first and last parallel set effectively driving all the current through a single cell.
3) Pos-to-pos and neg-to-neg on some parallel sets
4) No compression
5) Questionable history on the cells. (stored at near zero volts...???)
6) Possibly not LiFePO4
7) Possible mixed metals on the bus bars
I'll add one more:
8) A very large bank of cells that seems to be sitting out in the open and on the floor with nothing protecting the cell terminals and bus bars. Any dropped metal object could turn into fireworks. (I don't like 4 cells with exposed bus-bars..... 70 would make me pucker)
Only #1 in the above list has been confirmed to be the operating mode, but there are enough other oddities to make me think the system was likely involved in starting the fire. Beyond that, it is kinda hard to pin down what happened.
When people started immediately blaming the cells my reaction was "but we don't know that!"
Then the eagle eyes of the forum members identified a lot of questionable things:
1) No BMS
2) Wrong bus-bars on the first and last parallel set effectively driving all the current through a single cell.
3) Pos-to-pos and neg-to-neg on some parallel sets
4) No compression
5) Questionable history on the cells. (stored at near zero volts...???)
6) Possibly not LiFePO4
7) Possible mixed metals on the bus bars
I'll add one more:
8) A very large bank of cells that seems to be sitting out in the open and on the floor with nothing protecting the cell terminals and bus bars. Any dropped metal object could turn into fireworks. (I don't like 4 cells with exposed bus-bars..... 70 would make me pucker)
Only #1 in the above list has been confirmed to be the operating mode, but there are enough other oddities to make me think the system was likely involved in starting the fire. Beyond that, it is kinda hard to pin down what happened.