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Adam White

AA Lithium remaining capacity

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I'm sure many of you accumulate partly discharged AA lithiums. 

What is the most accurate way to measure their remaining life? 

 

Right now I've got this:

- a voltmeter? I gather that it's not a great measure unless their under a load

- a Pulse-load battery tester. There's no spot on there for lithiums and this guy says it's inaccurate because of the flat discharge graph. 

- Stick them in a Lectrosonics SMQV transmitter, and look at the battery readout on the receiver, either the voltage or the lithium setting. I don't own a single battery (smv) transmitter so it's not isolating a single battery either way.

 

Any other hacks that are more helpful?

 

Thanks in advance!

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13 hours ago, Adam White said:

Snip <<- Stick them in a Lectrosonics SMQV transmitter, and look at the battery readout on the receiver, either the voltage or the lithium setting. I don't own a single battery (smv) transmitter so it's not isolating a single battery either way.

 

Any other hacks that are more helpful?

 

Thanks in advance!

You can run a dual battery SM with just a single battery; the batteries are in parallel. The SMQV will run as if it were an SM.

Best Regards,

Larry Fisher

 

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2 hours ago, LarryF said:

You can run a dual battery SM with just a single battery; the batteries are in parallel. The SMQV will run as if it were an SM.

Best Regards,

Larry Fisher

 

Now that's a hack!

Thanks @LarryF!!

 

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I have done some tests on used batteries like that.  I put them in an SMa transmitter and logged the battery voltage on a Venue rack until the transmitter died.  If memory serves, the battery indicators in both the SMa and Venue seemed to be based entirely on battery voltage.  I was not able to come up with any consistent relationship between initial battery voltage and life expectancy.

 

Here is the graph.  Vertical scale is battery voltage.  Horizontal is minutes.  For reference we usually got 4-4.5 hours (so 240-300 minutes) on a brand new lithium in the SMa.

 

BatteryLog.png

 

My rule of thumb is that if you get a "good" reading for the first 5 minutes then the battery is not dead and you will get "some" use out of the battery - but don't count on any specific amount.

Edited by Matthew Steel
Walk back comment about minutes scale

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