Difference in values?

[The_Professor_2019]

This is Battery 2.

After being used and cycled a bit.

And the difference is really amazing

 

[The_Professor_2019]

And this is battery 1

Again, you will see that the chararistics are different from the first charger screen shot.

 

[Letitia]

If they are rewraps how do you know they are identical/same brand batteries? Did you remove the wraps?

 

[The_Professor_2019]

I did say supposedly identical

And that was the question, how can two supposedly identical batteries have such wildly different values?

Now they have run through some cycles, they are now a lot closer than they were, and now showing less than 10% difference to the wrapper value.

In the past, I did not have access to charger technology like this, and so I found the difference puzzling.

The batteries are part of the Kamry kit. It does have a scratch off label..

However the number provided is an older number. So this kit has been sitting on a shelf for a while.

I am waiting for my email to confirm the authenticity of the device. But it must be a couple of years since it left the factory....

 

[Mooch]

Li-Ion batteries don’t need any burning in but one stored for a very, very long time (years) can build up an internal layer of reaction by-products that can affect performance. Cycling the battery can help get rid of some of that layer.

Though that much of a difference in internal resistance indicates to me that other factors, external to the battery, could have been involved. These chargers are very sensitive to contact pressure and internal resistance can vary wildly depending on battery temperature and state-of-charge. A fully charged battery just slightly warm internally can have a much lower IR than one that is less than fully charged and cool.

Comparing two batteries requires that both be charged the same way, in the same charger slot, and allowed to rest the same amount of time before testing. Then, remove the batteries, discharge them, and repeat the test to see if there are any inconsistencies in the measurements. Then, swap slots and repeat the tests twice again. It’s not needed to do this every time once you have confirmed that the results are consistent but it should be done at least once before putting too much trust in our results. There are just too many variables otherwise that can affect the readings.

And, yes, it’s as boring to do as it sounds.

There’s probably no way for us to really know what’s going on though without buying several more mods with those batteries and testing them.