Since I am now slowly building up a small stock of Panasonic 3100mAh protected cells plus a couple of Xtar 2600’s , I decided to try to check (test) my old grey Ultrafire 2400mAh protected cells … Recently I had one Ultrafire just die … No volts and no response to trying to reset the protection (just in case it had popped) … Another failed on my home-made discharge test … These have been safely disposed of.
That left me with four grey protected Ultrafires to check … These were topped up and then discharged (in turn) with a bulb that draws 0.91 Amps … So it is not a high load … I monitor this all the time with my old Avo model 8 and check on occasions with my digital meter for more accuracy.
As soon as the load was applied , the cells dropped to at best 3.87V (cell 4) and then 3.82V (cell 2) , 3,75 (cells 1 & 3) … I discharged whilst monitoring the on load voltages for 75 minutes till the cell on load voltages reached 3.52 (cell 3) , 3.45V (cell 4) , 3.25V (cell 2) and 3.05 (cell 3).
On disconnecting the load , the volts immediately went up and eventually settled after a couple of hours to round about 3.8V … I then charged them all using my cheap charger boards and after charging , the cells were rested till the next day and measured … Cell 1 was 4.12V , cell 2 was 4.12V , cell 3 was 4.10V and cell 4 was 4.16V.
I am thinking of retiring the cells when they get below the 4.10V point … I’m not certain how much life there is still left in these cells , but since I am slowly building up a stock of the Panasonics I don’t mind retiring the Ultrafires … Cell 4 (4.16V rested) is now in my Skyline 1 and the two cells that are 4.12V (rested) are now in my Maglite 2D that is fitted with a Fusion 36 but will probably be replaced when my stock of new cells improves … I have cell 3 left as a dubious spare with its rested voltage of 4.10V.
I realise that my test is not very technical , but it does give me some idea of the cells performance.
In another few months , I will have enough new cells to retire all the old Ultrafires if necessary.
I am repeating the test on my two old (blue) Ultrafire unprotected cells … I don’t think they will be keepers as they didn’t hold up too well on my discharge test towards the end … The bulb was not as bright as with the other protected cells … They are on charge at the moment and I will know more in an hour or two … Not looking good though ! … I think they will be retired.
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