I have various 18650 cells which I use for Torch's, wildlife camera's and other uses but have never bothered checking how much capacity might be left in them. I have many cells sitting at various SOC an decided I would see what possible mah they might have left.
I haven't got discharge tester so just basing these findings on charge capacity from a known SOC start point.
Cell 1 .
LGHG2 20a 2500mah cell. Production date P125E, 125th day 2017 /May 5th.
2500mah cell with approx. 2440 capacity down to 2.8v
These I used as a 36v battery 10s 5p/ 100a then later reconfigured it for my Swizzbee as a 7s7p/ 140a.
SOC 3.6v/ 35% 3.6v -4.2v it had 1327ma capacity at 0.5a charge, resistance wise 18 ohm.
At this rate it suggests down to 3.2v there might be about 550 more mah of capacity and about 1870mah useable capacity.
Next I need to discharge it lower to see if capacity is higher or not.
Cell 2.
Samsung 26F 5.2A 2600mah cell. Production date 2E51/May 01 2014., 2 is version 2 of the cell, E year date 2014, 5 month May & 1 day.
2600mah cell with approx. 2580mah down to 2.8v
A low power basic cell used in many a cell pack. This one came out of my Oxydrive battery.
SOC 3.78v/55% . 3.78v - 4.2v it had 1585 mah at 0.3a charge, resistance was 37 ohm.
3.78 - 4.12v 1369mah , 4.12 - 4.2v 216 mah.
At this rate it suggests a possible 700mah more is available to 3.2v. and about 2285mah usable capacity.
Cell 3.
Panasonic 18650B 5a 3400mah cell. Production date 5609/2014 June 09, 5 year , 6 month and 09 day.
3400mah cell with approx 3400mah to 2.5v.
A low power high capacity cell, this I bought for a torch cell.
SOC 3.06v <5 ? 3.06v - 4.19v it had 2935mah at 0.5a charge, resistance 36 ohm.
3.06 - 3.78v 1360mah , 3.78 - 4.19v 1575mah.
Usable capacity to 3.2v about 2900mah. On charging it jumped from 3.06v to 3.24v in no time adding only about 60mah.
Cell 4.
Panasonic PD 10a 2900mah cell, Production date 2205/ 2012 Feb 22, 2 year, 2 month and 22 day.
2900mah cell with approx 2800 to 3.2v.
An earlier version of the more famed PF cell., a medium power cell.
SOC 3.61v/36%. 3.61 - 4.2v 1692mah at 0.5a charge/resistance 43 ohm.
Usable capacity to 3.2v about 2300mah.
I have about 20 of these cells which I use for torch light but they suck and are aged.
Another cell I tested only had 1139mah , SOC 3.76 .
Suggesting it only has about 1800 usable mah to 3.2v.
I haven't got discharge tester so just basing these findings on charge capacity from a known SOC start point.
Cell 1 .
LGHG2 20a 2500mah cell. Production date P125E, 125th day 2017 /May 5th.
2500mah cell with approx. 2440 capacity down to 2.8v
These I used as a 36v battery 10s 5p/ 100a then later reconfigured it for my Swizzbee as a 7s7p/ 140a.
SOC 3.6v/ 35% 3.6v -4.2v it had 1327ma capacity at 0.5a charge, resistance wise 18 ohm.
At this rate it suggests down to 3.2v there might be about 550 more mah of capacity and about 1870mah useable capacity.
Next I need to discharge it lower to see if capacity is higher or not.
Cell 2.
Samsung 26F 5.2A 2600mah cell. Production date 2E51/May 01 2014., 2 is version 2 of the cell, E year date 2014, 5 month May & 1 day.
2600mah cell with approx. 2580mah down to 2.8v
A low power basic cell used in many a cell pack. This one came out of my Oxydrive battery.
SOC 3.78v/55% . 3.78v - 4.2v it had 1585 mah at 0.3a charge, resistance was 37 ohm.
3.78 - 4.12v 1369mah , 4.12 - 4.2v 216 mah.
At this rate it suggests a possible 700mah more is available to 3.2v. and about 2285mah usable capacity.
Cell 3.
Panasonic 18650B 5a 3400mah cell. Production date 5609/2014 June 09, 5 year , 6 month and 09 day.
3400mah cell with approx 3400mah to 2.5v.
A low power high capacity cell, this I bought for a torch cell.
SOC 3.06v <5 ? 3.06v - 4.19v it had 2935mah at 0.5a charge, resistance 36 ohm.
3.06 - 3.78v 1360mah , 3.78 - 4.19v 1575mah.
Usable capacity to 3.2v about 2900mah. On charging it jumped from 3.06v to 3.24v in no time adding only about 60mah.
Cell 4.
Panasonic PD 10a 2900mah cell, Production date 2205/ 2012 Feb 22, 2 year, 2 month and 22 day.
2900mah cell with approx 2800 to 3.2v.
An earlier version of the more famed PF cell., a medium power cell.
SOC 3.61v/36%. 3.61 - 4.2v 1692mah at 0.5a charge/resistance 43 ohm.
Usable capacity to 3.2v about 2300mah.
I have about 20 of these cells which I use for torch light but they suck and are aged.
Another cell I tested only had 1139mah , SOC 3.76 .
Suggesting it only has about 1800 usable mah to 3.2v.