Recharge.......

[steve singh]

Hi, I have a question - battery is feeling sluggish on my friends E46 M3 when starting - he does quite a few short trips, but leaves his car standing a couple of days at a time.

Obvioulsy he will look into trickle charges etc. but in the meantime he was asking how long (rough and ready) would he need to drive to start charging the battery, over and above the charge taken to start the car up and what has been lost by being stood still?

Any rough estimates - would each journey being a minimum 20 mins around town suffice?

(btw his battery is relatively new & I've already told him he is doing his car no favours with short trips etc etc)

Cheers

[StottyZr]

I've never experianced a battery going flat under normal circumstances, are you sure his alternator is functioning correctly? Or his starter motor.

[Prof Prolapse]

Check the alternator.

Get a voltmeter. Engine on. Should read ~13.5 across terminals.

Lower = problem. Not necessarily new alternator though.