Battery Education - new cells accepting different levels of charge?

[HighlandRanger]

So I am finally moving to 18650's for everything going forward . . . . bought several sets of new Keeppower 18650s - the protected 3500 mah variety.

Put them in the charger for the first time before use and when they both finished, one said something like 2160mah and the other said 2650mah when they reached 100%
Same batteries from the same sealed packaging (ordered them and the charger new from Malkoff to accompany my new super hound dog - cool light).

I am charging the next set now but I notice they are starting off the same way - showing different voltages and different states of charge.

Question 1 - - safe to use these apparently different capacity batteries together?
Question 2 - - is this just a first charge thing and normal or a problem for the cells to accept so much less than their rated capacity?

I bought some similar cells (protected 3400mah, Keeppower) illum.com . . . . are there better cells to use? Cost not that much of a factor - just want the best cells with the most storage that wont blow up . . . . .

 

[vicv]

You just bought the cells. So they have a storage charge on them. The mah you're seeing has nothing to do with the capacity of the cells. That's just how many mah the charger put in them to fill them up. They weren't empty. Just different levels of charge.
The 3500mah cells are very good. Can't get really much better unless you need a lot of amps. The 3400 mah cells I wouldn't recommend. They lose a lot of performance for that capacity. They're an older tech and most other cells are better. Even ones under 3000 mah

 

[yellow]

Very good point!

Also: dont "count" that value, that Your charger types from charging into the cells.
You can just use what comes out!
So, if the charger has that Option - Check the value of the discharge mode.