Battery Help Please Now Sorted

right went to start bike a week ago and although the pump primed as soon as I pressed the button nothing the lights on the speedo went out then wouldn't come back on. so I switched the oximiser from the other bike and its been charging since the green light on the charger came on the next day and has been on since. went out today uncovered the bike Bonneville se 2010 and the same as last time pump exc but nothing else no head lights although I can just get the parking light to come on. put a meter on the battery 12.8v so cleaned the connections but no different. put the meter on again still around 12.8v but when I put the key in and turn on the ignition the meter goes haywire flashing between 1.v and around 4.asomething volts then as soon as I turn the ignition off it goes back to 12.8 ish volts. do you think the battery is fooked or something else. thanks in advance for any help.

 

thanks unfortunately the other bikes battery is somewhat smaller being a 125 so looks like ill have to go battery hunting.

 

so have bit the bullet and ordered a new battery will update when it arrives as to whether that sorts it out. fingers crossed

 

Yeah it does until I turn the ignition on then it just drops

 

Thanks for your reply's guys much appreciated

 

Battery ordered awaiting delivery hopefully tomorrow or Wednesday although living on the isle of wight although it shouldn't make a difference in delivery time it sometimes does. I will update at the earliest opportunity.

 

Will find out if battery is goosed when the new one turns up, keeping trips out to the minimum at the moment

 

Just had delivery update sometime Wednesday so maybe able to update Wednesday if it is delivered in time if not Thursday.

 

Battery arrived today fitted choke out clutch in pressed starter chuga chuga vroom very happy. For good measure I put the meter on the old battery showed over 13v connected an old camping light and when turned on the light flashed on for a second then went off and the meter started going up and down like when it was on the bike so wouldn't even power a light.