battery light

hi

have a 57 plate 118i automatic.

last couple of weeks, the 'half battery' light (apologies, im really NOT down with lingo!) has come on a few times. it only flashes up for 5 -10 secs and then goes away again, but the car seems to 'shudder' slightly when it does. it seems to happen intermittedly when i slow down without applying the brake and then speed up again (ie when i come up to traffic lights that are about to change and 'cruise' into them - again sorry for the terminology )


the battery was only changed about 3 months ago and i had a full service (at a BMW dealership) 2 months ago so i'm confused/frustrated as to why this would be happening.

any ideas what might be causing this and/or potential solutions?

thanks in advance.

Was the new battery registered? If not, there could be an IBS issue.

Tom

It was changed by a BMW engineer and registered. The IBS sensor was changed prior to the battery being changed, but then the problem (car not turning over fully upon ignition) persisted, so the battery itself was changed.

I've also noticed that the engine seems to 'splutter' very slightly when changing down gears and then changing up gears relatively quickly (eg when going round roundabouts)

Any ideas what might be causing this?

Thanks for any advise