Mark44
Retired Traveler with a yen for solar and LIFEPO4
I do not see this particular problem in any thread so here goes!
I just received my bench top power supply. I put all of my cells in Parallel to start out, and things seemed to go fine. I was charging at 3.4v and about 10.4A
Charging was taking place as my starting voltages on the cells was 3.01, 3.08, 3.09, and 3.10. After about 5 hours, the cells look like this: Cell1 3.238, cell2 3.227, Cell3 3.234, and cell 4 3.236. All in all fairly close. I put the cells back together in series, and put the BMS on (bluetooth xiaoxiang software controlling).
I have set my power supply to ~14.3V (dead open, no load), then connected and turned on the BMS. That is where I got my reading shown earlier.?
Now the sticky part. as soon as I turn on charging Cell 2 jumps to over 4V! The amperage swings wildly between 0 and 10.5 and every time the BMS tries to restart the charging, it soars again (the voltage) amperage drops, and it appears to go into overvoltage protection (I think). The other cells remain and the amperage is appropriate to charging (10.5 or so)
Any ideas on what happened? How can I test to see if the one cell is a runner, or if I have an issue with my BMS? I am going back to Parallel charging for now since that doesn't seem to hurt the cells. Indeed the cells seem to have balanced quite well in the short time they have been charging in parallel. Although that may be an illusion at this point.
I really need the brain trust here to come through with some sage advice, as this is my first LIFEP04 pack, and I do not want to repeat any errors I might have made. Thank you in advance for your time.?
I just received my bench top power supply. I put all of my cells in Parallel to start out, and things seemed to go fine. I was charging at 3.4v and about 10.4A
Charging was taking place as my starting voltages on the cells was 3.01, 3.08, 3.09, and 3.10. After about 5 hours, the cells look like this: Cell1 3.238, cell2 3.227, Cell3 3.234, and cell 4 3.236. All in all fairly close. I put the cells back together in series, and put the BMS on (bluetooth xiaoxiang software controlling).
I have set my power supply to ~14.3V (dead open, no load), then connected and turned on the BMS. That is where I got my reading shown earlier.?
Now the sticky part. as soon as I turn on charging Cell 2 jumps to over 4V! The amperage swings wildly between 0 and 10.5 and every time the BMS tries to restart the charging, it soars again (the voltage) amperage drops, and it appears to go into overvoltage protection (I think). The other cells remain and the amperage is appropriate to charging (10.5 or so)
Any ideas on what happened? How can I test to see if the one cell is a runner, or if I have an issue with my BMS? I am going back to Parallel charging for now since that doesn't seem to hurt the cells. Indeed the cells seem to have balanced quite well in the short time they have been charging in parallel. Although that may be an illusion at this point.
I really need the brain trust here to come through with some sage advice, as this is my first LIFEP04 pack, and I do not want to repeat any errors I might have made. Thank you in advance for your time.?