Hello all,
Glad to be here... no no... please dont stand up
anyway... I have been interested in building a powerwall of sorts for a while now... I have bought tons of batterys... shucked a number of 18650's and I landed on the SPIm08HP as a battery that I would like to build into a powerwall...
My current(first) battery that I currently have setup on the bench is a 7s3p battery that I fully charged using a daly 30a BMS... and today was the first day that I wanted to give it a good test... I bypassed the BMS and directly attached a 1500w inverter and put a load on it with a 1200w heater... the tested started out well and I manually monitored the voltages of the cells closely... after around 40mins the first group of cells started dropping drastically to 1.5v while the other 6 groups of batteries were around 3.56v... I would think that this means that one of the three cells are defective...
Prior to this... I checked all the cells for voltages and separated them based on the voltages... and after 2 weeks I confirmed that they were still at the same voltage... I built the battery pack and charged them to full... and after a week I ran this test... prior to this test the first bank(the one that died much faster then the rest) it tested lower then the other groups of cells...
how might I figure out which of the 3 cells is bad or is this to be expected of batteryhookup batteries and it will smooth out later...
Thank you for reading this much... I look forward to your wise input
Glad to be here... no no... please dont stand up
anyway... I have been interested in building a powerwall of sorts for a while now... I have bought tons of batterys... shucked a number of 18650's and I landed on the SPIm08HP as a battery that I would like to build into a powerwall...
My current(first) battery that I currently have setup on the bench is a 7s3p battery that I fully charged using a daly 30a BMS... and today was the first day that I wanted to give it a good test... I bypassed the BMS and directly attached a 1500w inverter and put a load on it with a 1200w heater... the tested started out well and I manually monitored the voltages of the cells closely... after around 40mins the first group of cells started dropping drastically to 1.5v while the other 6 groups of batteries were around 3.56v... I would think that this means that one of the three cells are defective...
Prior to this... I checked all the cells for voltages and separated them based on the voltages... and after 2 weeks I confirmed that they were still at the same voltage... I built the battery pack and charged them to full... and after a week I ran this test... prior to this test the first bank(the one that died much faster then the rest) it tested lower then the other groups of cells...
how might I figure out which of the 3 cells is bad or is this to be expected of batteryhookup batteries and it will smooth out later...
Thank you for reading this much... I look forward to your wise input
