Originally Posted by bbrowncods
I am new to charging LiPo's. I acquired a used 5000mah 6s battery of unknown history to use for ground operations and learning. I also bought a Hyperion 720i net3 AD charger. So I let them date, and I notice that the number 4 cell voltage is varying all over the map. I chock it up to a weak battery and go buy a new one of same amh and 6s rating. Below is the result of the end of the charge. What is going on? The 4 four cell is just like the used battery 4 cell. I just know that "one of these lines is not like the others".
You can directly measure each cell of your battery pack through the balance cable. Generally the individual cells go across the connector in sequence, where "Pin #1" is the negative pin, pin #2 is the first cell, #3 the second cell and so forth. Just connect your meter to #1 and #2 pins for the first cell, #2 and #3 pins for the second cell and so on. Some of the two cell receiver batteries may have the #1 pin negative, #2 pin both cells, #3 pin the top of the first cell.
If you look at the back of the balance connector you will usually see access to the locking part of the pins that you can connect a sharp multimeter probe to. Don't push to hard on those locking portions of the connector, you can bend them, and the pin will come out. (If so, just remove it, bend it back and slide it back in.) Also be a little careful, don't short out the cells with your meter probes.
If you are over the hill like me, you might need a magnifying visor to see what you're doing.
Digital multimeters are inexpensive nowdays, even the $5.00 Harbor Freight meter will serve the purpose for this type of work.
Take a look: