How do I do a cell test on my battery?
To do a cell test is not as difficult as it seems. Here is a link that will show you what to expect when opening the battery and cutting into the shrink wrap.
Please try to be as neat as possible with only enough cut away to reveal the tops of the cells and the end where he BMS is located. Please also keep in mind when cutting the wrap that it will need to be easily taped on again once the test is done or after cells or BMS is replaced. I find its pretty easy to make a cut along the top and one end to be able to remove the shrink wrap completely.
Also please keep in mind the battery is live so try not to short anything out. A short will not hurt anything but the spark will startle you.
First look at the BMS to ensure the large white plug is plugged in securely. Then to see if the other wires going to the BMS are attached properly and not damaged. Also, try to follow each individual red wire coming from the BMS plug to each individual place of attachment at the cells looks secure. If everything looks ok then proceed to testing the cells
As you can see the cells are all lined up in a row and the individual cells are all attached by wires with nuts holding then in place. To test each cell you will need a meter and you will work your way down all he cells one at at time. You simply touch the probes of your meter across each individual cell from one end to the other making a note of what each reading is. The screw cap and nuts are usually covered in clear silicone so you may not get a good reading on each cell. I find if you place the probes on the flat metal piece on the battery itself that it’s easier to get a good reading.
If all the cells are close in voltage then it could be an issue with the BMS.