I just completed an installation of 24 new 60AH GBS cells in my 7 year old C124 and it is running fine. The old cells were still serviceable but power and range was suffering.
The cell replacement was bigger than the big job I thought it was going to be - between getting all the cells charged and balanced on the bench-top and shuffled onto the battery tray. Then there were the estimated 400 screw removal and replacements with those 4-screw cell terminals and BMS connections. At least GBS now uses Torx-head screws. I also rigged a much improved syatem of restraint straps for both the 12-cell rows. CuMoCo did not restrain the cells well at all against swelling and so most of the old cells were visibly bulging.
I had only one glitch - after the first ride with the new cells last week, bad weather kept it in the garage, then yesterday evening, I attempted a trip out to the pub, but the scooter would, on any amount of slope, go 2-3 meters then shut off, to be repeated when the throttle was returned to zero and twisted again. The light on the Kelly was green, so I figured that it was another case of the BCU over-reacting to a minor condition. Fortunately, I have the BCU Access software and hardware which can do an OBD-style scan, configure, or-flash the BCU**. So I was able to immediately diagnose it as a open battery pack temperature sensor circuit at the connector to the BCU - which I was able to fix.
Why John and Eric programmed all these ways to leave a rider stranded over the most trivial detected faults is something I will never figure out. Could you imagine owning a car that shuts down every time a CEL code is thrown?
And while the big front fairing piece was off the scooter, I put LED headlight lamps in it - 50% more light at 25% of the power consumption!
The only thing left is to figure something useful to do with the old cells. I'm thinking of using them to build a UPS for my house - I figure they still have enough capacity to keep the refrigerator and (now all LED) lighting going for two days, - or in winter, the gas furnace and refrigerator and lighting going for one day.
Anybody else out there with a CuMoCo scooter still running?
**Only a few owners were able to get the BCU access and the BCU firmware before the "angel investors" of CuMoCo put a kibosh on it becasue they thought John Harding's programming, even just the compiled firmware code, was some kind of valuable intellectual property - which also went a long way to assure the failure of CuMoCO (and their investment).