Greendream
Off-grid Beginner
I am having a heck of a time with my bigbattery Llama's. Originally I had 3pc. They are oddball 14S batteries and charge to 51V. One of the batteries I have has a problem that bigbattery has said will be replaced after I ship it to them. There seems to be a problem causing the BMS to heat up to about 215F. The other two do not have hot BMS.
Now I am running on 2pc batteries in parallel. This is exactly why we got 3pc batteries for the redundancy.
I am watching my system like a hawk still because I have no idea how well these other two batteries are matched/balanced. Or if one of these two was causing the other BMS to work too hard to get so hot ??
Long story short, the batteries get to absorption, current tapers off very fast and 51V running to the parallel bank. Normal so far. Then I see the batteries drop down to 47.5V. Now I understand that's still quite high SOC but no AC loads were surging. This happened about 4 or 5 times during the 1hr absorption before it drops into float at 48V. While in float it never deviates from 48V by more than 0.1V.
What would cause this? Is it the BMS kicking in and disabling cells?
Bigbattery recommends 51V across the board for all stages. Low voltage cutoff is 43V. I've opted not to float so high but 48V is as low as my magnum will go from a 51V absorption charge.
If there is another problem battery I'd like to freight it back at the same time as the defective one.
Now I am running on 2pc batteries in parallel. This is exactly why we got 3pc batteries for the redundancy.
I am watching my system like a hawk still because I have no idea how well these other two batteries are matched/balanced. Or if one of these two was causing the other BMS to work too hard to get so hot ??
Long story short, the batteries get to absorption, current tapers off very fast and 51V running to the parallel bank. Normal so far. Then I see the batteries drop down to 47.5V. Now I understand that's still quite high SOC but no AC loads were surging. This happened about 4 or 5 times during the 1hr absorption before it drops into float at 48V. While in float it never deviates from 48V by more than 0.1V.
What would cause this? Is it the BMS kicking in and disabling cells?
Bigbattery recommends 51V across the board for all stages. Low voltage cutoff is 43V. I've opted not to float so high but 48V is as low as my magnum will go from a 51V absorption charge.
If there is another problem battery I'd like to freight it back at the same time as the defective one.