Radwagon 4 battery - Suddenly Dead

[james2022Radwagon4]

My battery woes with my radwagon4.  To start, let me say that the bike has been a workhorse.  It has been mostly reliable and fun to ride for the last 2 years.  I have about 2000km on it now.  Battery range has been consistently good, with no real signs of degradation.  Yesterday, I took the battery off the bike to charge it during the day (as I usually do when it needs to charge).  By late afternoon, the charger showed a green light, so I took the battery off the charger and put it back on the bike.  When I went to turn on the bike, the display flickered but did not come on.  I tried reseating the battery, checking the connections/terminals (for debris or water) and turning the key to different positions.  No luck.  I figured it must be a fuse.  I checked the fuses and they looked fine, but I swapped them with new ones anyway. I pressed the battery gauge on the battery and it flickered for a fraction of a second, but showed no bars.  I plugged it back into the charger but the light on the charger stayed green ? so it won?t charge it.  The battery itself has no damage and nothing changed from yesterday to today.  I tried another charger (from a friend with the same model radwagon), but still the charger does not detect that it is attached to the battery.  I know that it is not dead cells in the battery, because they do not go from 90 or 100% to zero in a day.  It could be the battery controller, or it could be some sort of planned obsolescence (of which of course I have no evidence).  I have checked all the forums I could find and checked any advice on Rad Power?s website.  Nothing seems to fit this particular situation, where I am confident that the cells are fine and the charger is fine. I have reached out to Rad but haven?t received a reply yet.  If anyone has ideas, or knows where I can buy the right replacement BMS (or other parts that might be faulty), I would really appreciate it (I am in Switzerland, by the way and lots of things don?t easily ship here). I use the bike everyday for school and work runs, so I am super eager to get my normal life back.  By the way, I understand that the battery is out of warranty, but I am surprised that Rad used such low quality materials that it failed so catastrophically without warning (of course, there are other imperfections with the bike stemming from poor materials, like the brakes and I won?t get into the tire recall fiasco).  Anyway, thanks in advance and even if non one has any ideas, if it happens to someone else, at least you will know you are not alone 😊.   

[DickB]

Open up the battery and check each group of cells with a voltmeter. They should be all the same voltage. If not, the BMS will shut down the battery.