[Seeker]

If the battery has dropped to 4V it may now be damaged. Assuming it isn't then running the bike a few minutes won't be enough to charge it, it would need to go onto a charger. Some battery tenders won't handle a battery whose voltage has dropped too low.

You'll need to check that you don't have something on the bike that is draining the battery (once it's charged) - you'll need a meter set to DC amps (set to 10A initially), you usually have to put the meter's positive lead into a different socket on the meter itself when measuring current. Connect the meter between the battery plus terminal and the leads that would normally go to the battery plus terminal (do not try and start the bike like this it will melt the meter, don't turn on the ignition either). The battery neg should be connected as normal. There should be a slight reading but it would be in the milli-amp range - so with the meter set to 10A, drop the range until you get a reading, it would typically be 20mA (estimate).
If you have a much larger number you would need to start by removing fuses and unplugging things and see when the current drain drops.


When everything has been returned to normal and the bike is running you should be measuring about 14.4 V DC across the battery once over idle.