Electric dead – smell of rotten eggs (hydrogen sulfur?)

This morning I wanted to start a nice tour, but 10 km behind the apartment door the box went out suddenly. Electric dead. Bike completely loaded, therefore the breakdown service carried home. In the garage suddenly this typical smell of rotten eggs is noticeable to me (sulphate hydrogen?) – voltage only 10.8V, the charger mots and says battery “sulphates”. The battery is not 2 weeks old – DELO HD GEL-BATTERIE YTX20HL-BS SAE 290A. Had that ever been someone from E uch? A brand-new battery gives up the mind? Or can it be something else? Just 3 weeks ago, I renewed the controller, battery, main fuse, flash relays and all the pears. See https://www.motor-talk.de/…/…ftail-battery-broken-t6836214.html