English translation -
I have the same problem and probably a faulty batch at YUASA.
In the fall the battery was removed and stored in a dry place, charged with a premium charger in the spring.
After starting the motorcycle, the error message ABS error and the "Check engine" indicator light, which were deleted while driving.
The next day battery voltage was only 12.5V and nothing worked anymore.
Bought a gel battery with increased starting power (up to 30% more power compared to conventional motorcycle batteries) 3 months ago for around €60 and have had no more problems since.
Having the same issue, can you send a link to the gel battery you brought please?
