Hi guys, my tiger has been sat in the garage for a few weeks, it wouldn't turn over yesterday to a point that the battery was on its arse and flooded, any way I changed the spark plugs today and jump started it, joy it started left it running for half hour runs fine but the ignition light is on, turned it off fired right back up, battery was new last year alternator is new cars only done 900 miles since 2008 Could the battery be goosed? Cheers

Multimeter will tell you for definate.

Could be a bad corroded earth....

I would suspect a quacked regulator or diodes in the alternator however.

First thing to do is check all the connections to battery and alternator are tight and also check the earths.

You should also charge the battery with a battery charger for at least 12 hours (16 to 24 is better) then let the battery rest off charge for a few hours. Then check the voltage across the battery (should be 12.5 v in UK winter temperatures 12.8 v in summer weather) then check voltage when starting the engine when turning the engine over the voltage across the battery should always be over 9v. If battery is in good condition and fully charged I would expect 10v from a small car battery 11v from a larger tintop battery. Below 9v ie falls quickly to 6v although may rise after a few seconds to 8v indicates a dead cell in ther battery.

If passes the above then check the charging voltage by measuring voltage across the battery with engine running at a fast idle. Voltage should be 13.4v to 14.9v with engine running at over 1500 rpm. Then check battery voltage at 2,500 rpm with head lights on again it should be 13.4 to 14.9 volts. Then switch the headlights off with engine still at 2,500 rpm at no point must the voltage jump above 15v .

give the alternator a bit of a tap,if no good give it a bigger tap (best done running) thats the car not you

Thanks guys no it was me I must of disturbed the connections to the alternatior when i was doing the last plug that will teach me to leave the wires dangling lol