What can I say about this battery? In a Vstrom 650 K8, it lasted a full 10.5 years, and I should mention that the bike also experienced some periods of inactivity of 1-2 months in between, and I never charged it with a charger (that one was made in Japan). So from 03/2008, it left me one day in September 2018, and I bought the same one again, but not made in Japan (maybe Indonesia or China, I don't remember), which today, 27/11/2021, after almost 3.5 years, shows 12.90 V after a measurement I did after 3 days of inactivity. So it's doing just fine.
EDIT: IMPORTANT for it to last long, as a friend said, the initial activation and charging should be done correctly. I got it completely sealed and activated it myself. With appropriate protective measures, mainly for the eyes, you pour the ready vials (which are in order) with oxygen and simply place the cap on the holes without sealing it for 2 hours so that the reaction occurs and the Volts increase, and then you close the cap and charge it with a very slow charge until fully charged. If you buy it ready from a workshop, they pour the oxygen, seal it immediately, and charge it hastily, so the battery comes with a reduced lifespan from the first moment.
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Final update 28-08-2024. I had replaced it 6 months ago (February 2024) because due to my mistake, I had locked the bike in the parking position, resulting in the lights staying on and it dying for the first time last year. Later, since I recharged it, I had revived it again on a small island where I stayed for a month for work, and I started it 10-15 times in a row for distances of 200-300 meters, and it didn't have time to recharge, resulting in it dying for the second time.
From then on, it could handle 1-2 starts in a row but no more (maybe in the summer it could handle more), so I replaced it, but it still holds a satisfactory charge, and I have it for various experiments in the warehouse with lights, small motors, etc.
5.5 years that could have been 6 or 7 with a little care.