Delta-V
Solar Enthusiast
- Joined
- Sep 20, 2019
- Messages
- 97
Well, did another capacity test with 8 of my Xuba 280Ah EVE cells. Staying on topic, ha ha.
Was aiming for an upper limit of 26.80V. Took some doing again to charge the battery to a steady resting voltage. I'm learning how frustrating CC/ CV charging can be, time consuming when trying to get to a final resting voltage (somewhere in the middle). I let the battery rest overnight and it still dropped to 26.76V. I went with it anyway, close enough. Start of my morning, working from home.
Lower limit was 24V under some load. Got about 61% capacity usage (4,420Wh / 7,168Wh or 172Ah / 280Ah). Was expecting closer to 80% (5,734Wh / 7168Wh). Perhaps it's my testing method. Trying to be more real-world as opposed to perfect testing conditions. The C-rate was up & down throughout the day (183W - 1,500W), averaging ~440W/h (<0.1C) in about 10 hours. Fridge would kick on & off, brief coffee warm-ups with the microwave, lunch break, etc....
1st Pic - Begin test, Inverter off, resting voltage, 26.76V, cells reasonably balanced
2nd Pic - Inverter on, minor drop in voltage
3rd Pic - Running home office, Frig, & coffee maker, 1.5Kw peak for a few minutes
4th Pic - Hit lower limit of 24V under load
5th Pic - Powered everything off, Inverter still on, voltage recovers a bit
6th Pic - Inverter off, resting voltage 24.29V after half an hour or so
I was using the ISDT BattGo meter (right) voltage as reference, as it matched closest to my hand-held multi-meter (not-shown). Using Drok meter (middle) for total Wh or Ah. There's a little voltage offset between meters, but all are in the same time-line. Perhaps I should use the inverter voltage instead. It tends to be the lowest compared to the rest.
Was aiming for an upper limit of 26.80V. Took some doing again to charge the battery to a steady resting voltage. I'm learning how frustrating CC/ CV charging can be, time consuming when trying to get to a final resting voltage (somewhere in the middle). I let the battery rest overnight and it still dropped to 26.76V. I went with it anyway, close enough. Start of my morning, working from home.
Lower limit was 24V under some load. Got about 61% capacity usage (4,420Wh / 7,168Wh or 172Ah / 280Ah). Was expecting closer to 80% (5,734Wh / 7168Wh). Perhaps it's my testing method. Trying to be more real-world as opposed to perfect testing conditions. The C-rate was up & down throughout the day (183W - 1,500W), averaging ~440W/h (<0.1C) in about 10 hours. Fridge would kick on & off, brief coffee warm-ups with the microwave, lunch break, etc....
1st Pic - Begin test, Inverter off, resting voltage, 26.76V, cells reasonably balanced
2nd Pic - Inverter on, minor drop in voltage
3rd Pic - Running home office, Frig, & coffee maker, 1.5Kw peak for a few minutes
4th Pic - Hit lower limit of 24V under load
5th Pic - Powered everything off, Inverter still on, voltage recovers a bit
6th Pic - Inverter off, resting voltage 24.29V after half an hour or so
I was using the ISDT BattGo meter (right) voltage as reference, as it matched closest to my hand-held multi-meter (not-shown). Using Drok meter (middle) for total Wh or Ah. There's a little voltage offset between meters, but all are in the same time-line. Perhaps I should use the inverter voltage instead. It tends to be the lowest compared to the rest.
