Defective ZTS, or bad batts?

[KeyGrip]

Not twenty minutes ago I got my mini ZTS battery tester, and it won't give me a % on my old cells, of any type. Cells that should at least be around 20% get nothing. The indicator lights flash in their little sequence, it clicks, then nothing. Are my cells really that worn down?

 

[DonShock]

Usually, this is an indication that the cells are very low. Try a new cell that you are sure is at full capacity just to make sure the ZTS is working.

 

[KeyGrip]

You're right, the cells I was testing are very, very low. The biggest surprise came when I tested the cells in my L4. They were at 20%, but they still power up the light at near full brightness. Thanks for the quick reply, I'm going to go testing.