Hi All,
I purchased a 120Ah 12v LiFePO4 battery which specified a maximum continuous discharge of 150A as I have a 2000W inverter connected which needs occasional, short term heavy draw.
I've put a 120A fuse on the battery which to my understanding means the maximum discharge C-rate is 1. I've found that even when discharging at around 90A / 0.75C the voltage of the battery immediately drops way down to 12.1~12.3v despite starting with a full charge.
According to the SoC chart published by the manufacturer 12.5v is equal to 20% capacity. The only discharge curve they publish is at 0.1C / 12A which shows from 35% ~ 95% SoC the voltage should only vary between 12.8v~13.1v.
This is probably my misunderstanding, but I would've thought a battery manufacturer advertising a high continuous discharge current would translate as that battery being capability of holding voltage under such loads.
This comes to an issue I had recently where I was off grid camping and when I went to bed around 10pm the battery voltage was 13v. The load at that time (with everyone else asleep, so would not have changed) was around 5A, so with 13v indicating the battery was anywhere between 70% and 85% full thought I had plenty of capacity to last until morning. 5 hours later I woke up to the 10.8v low voltage disconnect alarm of my BMS and confined the battery was in fact sitting at 10.5v.
Would appreciate if anyone could assist with making sense of this for me.
I purchased a 120Ah 12v LiFePO4 battery which specified a maximum continuous discharge of 150A as I have a 2000W inverter connected which needs occasional, short term heavy draw.
I've put a 120A fuse on the battery which to my understanding means the maximum discharge C-rate is 1. I've found that even when discharging at around 90A / 0.75C the voltage of the battery immediately drops way down to 12.1~12.3v despite starting with a full charge.
According to the SoC chart published by the manufacturer 12.5v is equal to 20% capacity. The only discharge curve they publish is at 0.1C / 12A which shows from 35% ~ 95% SoC the voltage should only vary between 12.8v~13.1v.
This is probably my misunderstanding, but I would've thought a battery manufacturer advertising a high continuous discharge current would translate as that battery being capability of holding voltage under such loads.
This comes to an issue I had recently where I was off grid camping and when I went to bed around 10pm the battery voltage was 13v. The load at that time (with everyone else asleep, so would not have changed) was around 5A, so with 13v indicating the battery was anywhere between 70% and 85% full thought I had plenty of capacity to last until morning. 5 hours later I woke up to the 10.8v low voltage disconnect alarm of my BMS and confined the battery was in fact sitting at 10.5v.
Would appreciate if anyone could assist with making sense of this for me.