Battery charger questions

I parallel charged 6 x 3S, 450 mah lipo batteries on my ISDT 150 W charger twice with one slow flight, ending at 3.9V in between). Both times the ending charge is as follows:

Multimeter: V_cell = 4.2, 4.2, 4.18
Charger: V_cell = 4.2, 4.2, 4.2

Is the 0.02 V error fine in this case, since it’s on the low side?

My batteries internal resistance (given by the charger after charging to 4.2V) is as follows:

First Charge: R_cell = 5.4, 5.3, 5.7 mOHM
Second Charge (After slow flight ending at 3.9 V): R_cell = 5.6, 5.4, 6.1 mOHM

Is this okay or is the increase in internal resistance bad?

Thanks!

The .02 v diffrence isnt that big of a deal yet, i would try to charge just that battery and see the end voltage on each cell. But i would not stress unless u are drawing voltage to low below 3.2 volts and your packs are puffing or coming down really hot. Just monitor the voltage. This is just my opinion and ive been flying with lipos since they have first hit the market.

Awesome. The 0.02V difference is for all the batteries when I am parallel charging and always on the third cell, so it must be a charger problem. I figure that 0.02 V isn’t terrible, but was just asking to be sure.

The internal resistance increasing is a bit worrying, but I know that these chargers are not that accurate. Right?

Wildly inaccurate, when it comes to resistance. Don’t worry about it.

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Yeah no worries like i said unless you put one battery on and it says one cell at 4.2 , 4.2 , 4.0 …then the next time you put it on a balance charge and now you notice that same battery cell is now 3.8 and it keeps doing that or keeps dropping voltage in that 3rd cell then you have a problen and then discontinue use… Other than that fly it like you stole it and have fun…

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