Originally Posted by akschu
I have a 8s pack I accidentally ran to lvc because I thought it was charged and it wasn't. I would like to compare it to another identical 8s pack using the ESR meter, but the instructions say only up to 6s.
Can you provide a wiring diagram to test individual cells in larger packs?
You can use the balance connector as the power connector as although the measuring pulse is 16A it is only present for a few milliseconds so it cannot cause any overheating or damage. Therefore you need to make up a power lead with two flying male pins which you can plug into any two positions in the balance connector. If you want to measure cell 3, for example, you can plug these two pins into positions 2 and 5 or 6 in the balance connector and the cell search lead into positions 3 and 4 and it should measure cell 3. Draw the schematic of the pack out in front of you and you will see the logic of it.
By moving the pins up the connector, ensuring that there is always only 6 cells max between the pins, you will be able to measure all the cells. To measure cell 1 and cell 8, you should use the the (-ve power connection + 1 pin) and the (+ve connection + 1 pin) respectively.
This means that the leads carrying the current are never the leads measuring the cell voltage so that the Kelvin principle of measurement is maintained. Thus the high voltage drop at the power connections into the balance connector will not be included in your measurements.
The overiding requirement is that you do not apply more than the voltage of 6 cells into the two power leads
If you do you will damage the unit. Two customers have proved it so far!!