Is it a wet cell battery? The reason I ask is I had a starting issue until I realised the battery acid was well low.
Think it’s a sealed battery. It’s one of these (the right one, obvs) https://motorcyclepartswarehouse.co.uk/mbt14b4-motobatt-agm-motorcycle-battery-12v-13ah.html
Which means lasts two years then chuck away My 911 is also dead. That lives on a maintainer, never had issue when it’s been on but it’s dead entirely. Again showing over 12v but won’t even light up ignition The scurge of having vehicles and not using them enough. Tbh since Covid bollox I barely get out these days other than bit of golf, often on my own
Charger/Maintainer forum offer here: https://www.ducatiforum.co.uk/threads/lithium-and-lead-acid-battery-charger-for-just-£34-95.101407/