On 29/01/2020 02:36, jbeattie wrote:

snip

Is this a trick question? If your battery is showing 8v, it's not
dead. No? Why would load matter -- except for measuring capacity. I
understand the battery may have a protection circuit, but wouldn't
that decrease the measured voltage?

I don't have an EE degree, but I measure batteries with a multimeter
all the time to see if they are alive or dead, and if one showed 8v
it would not be dead. I think you messed something up. Just check
the quality of your connections. Do you have the little tool?
https://www.youtube.com/watch?v=OkdY9q-u5Dk If you're not fishing
wires, it's really pretty fast and easy. Its the fishing that takes
time.

A battery will often show volts but not be able to pwoer anything. You
should measure the voltage in circuit if possible (i.e. under load), or
just check the voltage of an old PP9 you have lying about (smoke
detector battery). If you have a *lot* lying around.

https://www.youtube.com/watch?v=8hwLHdBTQ7s