Welcome to the fifteenth installment of this relatively unexciting experiment to see how long a modestly sized “unknown-name” Chinese Li-Poly power bank would last under continual cycling. Those who have been following along will know just what this means – another 50 cycles have been added to the tally, bringing the total number of charge/discharge cycles to 750 since the commencement of the experiment, or 766 since manufacture.
The degradation trend initially seemed to follow some sort of linear-ish/logarithmic trend until the suspension of the experiment. Storage of the fully-charged power bank seemed to cause a step change in capacity and a newer, steeper degradation trend began to establish.
From there, the latest 50 cycles seem to show an unusual slight capacity recovery (within my expected metering error) and what appears to be mostly a suspension of the formerly visible linear degradation trend. The lowest point in the latest 50 cycles didn’t fall below the lowest point previously established.
The unit still has a long way until a total loss of capacity. Its longevity was entirely unexpected to me, given that this is a “whole system” test of the cell, the charging circuit, the boost converter, and the connectors. Nothing has failed throughout the testing so far.
This experiment has gone on for much longer than expected, and yet, there’s still plenty of life in this power bank it would seem. This is rather unexpected, but goes to show that even “unknown-name” devices could work well if well designed and built with well made components.
A sample of one isn’t particularly representative of the population, but such “real” testing takes a lot of time and effort, as well as quality test equipment, so at least there’s one data point here.
I think I might continue the experiment … but I have a feeling that most consumers won’t even use their power bank this much before it gets retired (maybe for a faster charging unit with Qualcomm QC, a larger unit or one with flashy “synchronous” charging abilities, etc.). Next report when the unit reaches 800 cycles (816 from new).