Will idling an engine charge the car battery?

[JohnL]

Fast charging of a flat battery (as you get from the alternator) is harder on the battery. A slow charge ('trickle' charge, as you get with a battery charger) is less harsh on the battery. Battery chargers are cheap....

[Alpine]

Kmart 25% off automotive items sale - so got one of these today:

http://www.projecta.com.au/catalogue/cid/3/asset_id/18

Tried charging it up this arvo - light went from orange to green in about 5 hours. Works well.

[JohnL]

Claymore,
You seem to know more about this electrical stuff than me (I hate auto electrics!). If the charge light on the dash is off with engine running, is it a safe assumption that the battery is charging from the alternator? I've always made this assumption.

I do know that in the bad old days (when cars had dynamos as opposed to alternators, generating DC directly rather than AC that is then converted to DC) that charging at idle was at best marginal and likely to be less than the currect needed to run the ignition system. So, with an old fashioned dynamo the answer to the original question is probably 'no', but with a more modern alternator it's most probably 'yes' (unless there is a problem with the system).

[JohnL]

^ Thanks.