Should I disconnect charger to test cell voltage?

Famtraveler24

Solar Enthusiast
Joined
Jul 22, 2020
Messages
104
Hi all. I am doing my first top balance of a 4s 280ah pack. Now in parallel stage.

When checking individual cell voltage, should I disconnect the charger? If not, I assume I am not getting accurate readings and am only testing voltage drop?

Thx.
 

DThames

Photon Sorcerer
Joined
Nov 22, 2019
Messages
1,429
Not sure this is the answer to your question but if the charger is on, the voltage at the battery terminals may not be the true battery voltage. Turn the charger off to measure battery voltage. Disconnect the cells from each other if you want to see the voltage of a given cell.

All cells have an internal resistance. If there is any current flowing, that resistance is in series with the battery/cell and you will measure its drop. You can't get inside the cell, past this internal resistance. So be sure to measure with zero current flowing if you want to get the best cell voltage value.
 
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