AW 14500 protected cell - reads 4.07 volts but won't power my LF5

[Gatsby]

I have two AW 14500s, both purchased second hand, that I use with my Liteflux LF5. One cell seems to be working just great charging with my Nano CR123 charger and alligator clips. The other cell I popped in for the first time the other night after a quick charge - and it worked for a bit then would not operate properly setting off the discharge protection. I was a bit surprised when I measured it it read 4.02v on my multimeter. The nano would not charge it (turned red for about 3 minutes then green) and it continues to not be able to power the LF5 for more than a few seconds before flashing.

I'm guessing it is dead for some reason and don't want to roll the dice with li-ion batteries but I was just curious if anyone thinks it could be revived?

 

[Illum]

the protection circuit sounds fried, 4.07V measured open circuit is relatively useless as it would fall quickly if load is applied
I think the only thing you can do is to remove the outer casing of the protected cell, separate the cell and the protection circuit and cycle the unprotected cell

 

[Gatsby]

the protection circuit sounds fried, 4.07V measured open circuit is relatively useless as it would fall quickly if load is applied
I think the only thing you can do is to remove the outer casing of the protected cell, separate the cell and the protection circuit and cycle in unprotected cell

Since the LF5 has overdischarge protection built in I'm not necessarily unhappy to use an unprotected cell - I just like the belt and suspenders of a protected one! This is mostly a backup to my primary cell so this might be a good solution to keep from trashing it at least!

 

[Illum]

well before you go ahead and charge it, measure the battery voltage...if it sags around 1.5V-2V its probably not worth the risk of charging it as its over discharged beyond 3V

I don't remember who gave me this, but I printed it out and posted on my wall [relative capacity based on open circuit voltage of a 4.2V li-ion]
100% -- 4.20V
90% -- 4.00V
80% -- 3.95V
70% -- 3.92V
60% -- 3.87V
50% -- 3.82V
40% -- 3.79V
30% -- 3.77V
20% -- 3.74V
10% -- 3.68V
5% -- 3.45V
0% -- 3.00V