I jumped on the bike on Saturday, put the keys in the ingition and turned it on but everything was dead. I checked the battery and it wasn't even reading a voltage. I put in on a trickle charge until the voltage was above 14V, connected it all up and still nothing, so I checked the voltage again and it was gradually falling at about 0.1V per second!
I then disconnected all of the leads to work out what was drawing power, but it still kept falling. I presume the battery is completely knackered, but even when connected a second battery in parallel to jump start it, once I took the 2nd battery away the voltage of the knackered battery was jumping all over the place, to the extent that when I turned ON my lights or heated grips etc, the voltage went up to over 12V, and when I turned them OFF it was going down to 10V.
Is it purely a knackered battery or might there also be a fault with the regulator?? I don't want to buy a new battery to knacker that one as well if something else in the circuit is causing a failure.