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I ordered some lithium batteries (like this)

I'm planning to test the specs like

-Maximum Continuous Discharge Current

-PCM Discharge Cut-Off Voltage

-PCM High Temperature Cut-Off

In what other ways can I evaluate these batteries? Any suggestions-comments would help!

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  • \$\begingroup\$ You have the specs. There is nothing else! \$\endgroup\$
    – Leon Heller
    Commented Aug 24, 2018 at 18:39
  • \$\begingroup\$ Weight, volume, density, energy density, ... \$\endgroup\$
    – Transistor
    Commented Aug 24, 2018 at 19:08
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    \$\begingroup\$ Be very careful doing this. If you accidentally exceed the maximum ratings you could have a nasty fire on your hands. \$\endgroup\$
    – Elliot Alderson
    Commented Aug 24, 2018 at 19:29
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    \$\begingroup\$ Testing maximum continuous discharge current can be destructive. Same with testing high temperature cut-off. Are you prepared to sacrifice batteries for testing, and are you prepared to deal with electrical/chemical fires? \$\endgroup\$
    – Dampmaskin
    Commented Aug 24, 2018 at 23:53
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    \$\begingroup\$ Battery specs can be roughly separated into a) performance characteristics (capacity, self-discharge, discharge graph etc.) and b) maximum ratings (the ones on your list). "Testing" by end-users usually involves the former. Maximum ratings were already tested in laboratory and set by manufacturer as safe limits. You cannot "test" for them unless you exceed the limit, see the smoke and say "oops... yeah, those 100 degrees is really correct thermal cut-off" \$\endgroup\$
    – Maple
    Commented Aug 26, 2018 at 4:38

1 Answer 1

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I ordered some lithium batteries (like this)

I'm planning to test the specs

Be aware that doing this safely and accurately will involve going to considerable amounts of effort. You'll need to get testing information from the manufacturer for ambient temperature and other conditions if you wish to verify their values, but if you wish to obtain data that is kept proprietary or have other reasons, by all means:

-Maximum Continuous Discharge Current

This will be affected by ambient temperature which will necessitate measuring and/or preferably controlling ambient temperature for accurate results. You will need a current regulator to ensure current or power stays constant as the battery voltage changes, depending on which you care about. This test could damage the battery, and for a quality battery it is very unlikely that the battery will fail the test under correct conditions, but you could measure actual performance, which likely slightly exceeds rated. This test could also be used to measure Ah at a lower current or actual performance of the battery with a PWM load with average 25A. Potentially useful information, but especially with the latter, could be a destructive test.

-PCM Discharge Cut-Off Voltage

If you monitor the voltage as you run the battery down, this will be easy to verify.

-PCM High Temperature Cut-Off

Operation of the switch should be easy enough to verify, simply warm the battery slowly and measure the temperature at which some tiny load (15ma LED or such) cuts out. If you want to measure real world performance or conditions in which the battery heats itself to shutdown, this could be a very expensive test.

In what other ways can I evaluate these batteries? Any suggestions-comments would help!

Internal series resistance might be of value to you. The thing about testing a battery for these safety properties is that if you're in a situation where the precise properties matter and you need to know badly enough to risk batteries in the test, it is probably worth considering improving your safety margins, physically thermally protecting the battery (protect from high ambient or cool it if necessary), and testing it under actual worst case conditions.

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