New LIPO battery check


#1

I bought a new 1550MAH 4cell battery Tattu R-line.
The thing is when I charged it with my LIPO charger saw that it started with all cells 3.8v per cell,and finished at 4.19,4.19,4.19,4.20.
After the charge I check with a simple battery tester from banggood and it showed 3.18,3.18,3.20,3.20.
My battery charger is this one in the video https://www.youtube.com/watch?v=bcQU1fUZjDY
Is the battery fine? or should I sent it back to the seller?
What is more accurate tester for the cells the LIPO charger or the battery tester?
And my charger asks me for the MAH of the battery and its 1550MAH, should I insert 1500 or 1600MAH in the charger?
Thank you guys.


#2

3.8v per cell is storage charge which is correct when you buy them new.

4.20 is fully charged per cell a little difference can be expected as nothing is perfectly calibrated.

but showing 3.18 per cell after a change is not good.
Can you check the voltage with a different meter that one may be bad.


#3

I dont have a different tester, maybe I charged it wrong? maybe i’ll discharge it a little and charge it to 1500 or 1600 MAH?
Do you have a link to a reliable battery tester?


#4

I did a small run with the New batt and another 1 month batt I have, discharged them untill 3.9v~ per cell kinda.
Then I put each one of them in the charger untill both of the batteries charged untill 4.19-4.20v per cell then the charger stopped.
I checked with the battery tester after they both charged and in the old 3 cell batt showed 4.17,4.18,4.21 and in the new 4 cell batt I dont remember but also an odd result.
I guess its the battery tester that is faulty?


#5

could be.

You would need another one or a volt meter to be sure.