Charging: jump in voltage during CV phase?

[null]

Charging my OG Sherman with a MCU controlled 10A charger I recently noticed this bump in the CV phase.
The jump is about 0,2V right up before it starts to curve again.

Anyone see an explanation to this? (edit: it was the charger fan turning off)
If it is just the chargers programming it wouldn't matter I suppose. (again, not sure if it was always like that)
But if it was a symptom of an actual problem it would be best to figure it out.

Thanks for any help!

edit: I figured out it happens at the moment the cooling fan of the charger stops, so at least its not something strange on the battery side.
 

Edited May 20, 2023 by null

[alcatraz]

It almost looks like an error. Like the time for those values are unavailable. I say that because it jumps in voltage as and continues charging like as if it never stopped. The resulting curve is basically a continuation of charging before it changed.

Then again, it could be some sort of balancing circuit that's turned on. Balancing is then finished and the final charging continues.

[alcatraz]

It can also be some sort of temperature reaction. On phones charging slows down if the packs heat up past a certain point, then if they cool the current is bumped up again. 

[null]

Thank you for the replies and the possible theories @alcatraz. It turns out it happened just when the chargers cooling fan turned off, probably resulting in a jump in current. Thus while not elegant, it probably doesn't matter much, and at least isn't the batteries acting strange.

Thanks again and have a nice day.