Greensaver have been very helpful in providing technical details regarding their batteries.
They provided the following diagram of the top of the cell including the interconnecting links.
I drilled 5 holes in the top of the battery according to their diagram and measured the voltage of the 6 individual cells. The battery is measured at full charge. This battery has been (unfortunately) over discharged about 35 times and is only about 1/2 new capacity. A battery that has been cycled like this should exhibit significant imbalance between cells if the cells are not almost identical.
The results below are measured with a meter (not pictured) with 4 decimal places:
Cell : Voltage
+
1: 2.2402v
2: 2.2456v
3: 2.2452v
4: 2.2541v
5: 2.2490v
6: 2.2458v
-
Average cell voltage is 2.2466 volts. This is 100% charged including some surface change.
The standard deviation is .004616
The range is from 2.2402 to 2.2541. A difference of 0.0139v (13.9mv) or 0.6205%
I am not an expert in battery chemistry but this seems to be quite good.
Comments welcome.
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