I think most fail gradually: they'll charge to 98% then 95% then 80%... then fail completely. I have a 2015 SR that failed suddenly: worked fine and then just did not charge failing the self-diagnostic. There's a fuse in the charger wiring harness that can cause these symptoms, but was not the case in mine. I plan to take the charger off the bike once it goes into winter storage and see what I can dig up. So for me the question is: how did the charger fail and then how that was remedied?