Registered Forum User
Ducati Meccanica
Posts: 2,527
Join Date: Sep 2004
Location: Pulborough, W. Sussex
Mood: 900,900,851,750,750,750, 600,600,450,350,350,250
Two quick thoughts
1 - temperature makes a big difference to a battery thats not quite at its best - which is why leaving it on charge could make a difference cos the internal temperature will rise when charging.
2 - if you measured the volts at the battery terminals, thats not necessarily what is getting to the bike ! Measure the voltage from the frame to the starter solenoid input terminal to get a better picture.
(I've banged on about the battery earth terminal bracket before - the stupid little bolt on the right-angle bracket is a spline fit which can loosen and cause a duff connection. I centre-punched the back of mine and then soldered it up.)
Its this kind of duff connection that makes 'smart' chargers cook batteries too !