Is it just my luck? ... I went to fit a handlebar mounted sat nav holder on the Speedfour and adjusted the chain while I was fiddling around. Then went to take bike to fuel up and nada ...totally dead when I turned on ignition. I took the battery off and checked voltage ...8.2 volts. Probably not enough to fire it up? Anyways I've stuck that on charge for 24 hours and will again tomorrow. Thing is I only used the bike about a week ago and it was fine. Are Speedfours/ Triumphs in general prone to running down batteries when not in use every day?
I am thinking I left parking light on under the bike cover when I last parked it up...maybe. Will try again with a battery that has full voltage tomorrow
8.2 volts sounds like a faulty battery, unless you left something switched on ...... or a fault in the charging system, either way it sounds like a new battery as unless the battery is very new a full recovery is unlikely.
ok. easy fix. just charged battery for 5 hours at 1.0A. voltage went from 8.5v to 12.3 and bike started straight away. Now all I need to find out is why it went flat over the space of a week. I have left the negative battery lead disconnected until I use bike again and I will buy one of them Optimate trickle chargers to keep battery nice and charged.
12.3v is very close to half charged and could be detrimental to your starter clutch, I would be looking for 12.6 or 12.7 v on a battery that has been fully charged to around 13.0 and been left for a while.