It was almost a six months ago I went to charge the Gem and after plugging it in I did not hear the fan blowing so I unplugged it and disconnected the battery pack. I recently tackled both my 12V converter problem and ordered and replaced the Zivan fan( 612NGHH - ebm-papst, Inc. - Axial Fans | Galco Industrial Electronics ) but now I just get a sickly beeping and a yellow/orange LED.
While replacing the fan I also noticed the NTC 10 thermistor looked to have slightly desoldered so I removed it, tested it and soldered it back in place. I don’t know how I didn’t notice the relay it was leaning against had the cover melted but the relay is still operational as seen in this video.
Looking at it closer, I see some feedback resistors might have leaked. There are 4 pairs and each pair measure 50 ohm in-circuit and 100 ohm(brown/black/brown) in parallel is 50 ohm so they seem ok.
While I figure out what to do, or how to fix the Zivan, I’ve wired in series 2 42VDC 2A scooter chargers which will take 2 days to charge from 50%( 20S 116Ah Leaf modules ).
Tough to find a simple 4-5A 72V(84V) 20S charger which has adj voltage cuttoff feature since I only want to charge these to 4.0V/cell max.
got the cells up to 3.95V before needed to pick up the kid at school and quickly put it back together, minus the Zivan charger, and $%$#$!#@$&)** nothing worked. I had to jump into the diesel truck and do the pick-up. Once back home I found this wire-diagram which shows the key control of the power relay is through the charger so you can’t leave while pulled in I guess. All I needed to do was to jumper the green and red spade connector’ed wires for operation without the charger. Doh.