Ford Explorer Battery Gauge Needle moving a little on idle

Hi,

1998 Ford Explorer XLT 4.0L SOHC, 228000 km

Just replaced alternator (died a tragic death while 700 km from home), had a jump start during the problem, as I completely flattened the battery, but all seemed fine. Drove home OK after replacing it with a brand new one. Battery holding charge and no problems starting a couple of days later.

Noticed when idling at the lights last night in a storm that the battery gauge needle was flickering down and then up, it was running a little lower than the usual point it occupies. Also noticed dash lights dimmed a little when the needle dropped. Mind you the cd player, heating, fan, wipers and indicators were on as well as this I had my foot on the brake and was just after turning the steering wheel. Noticed the idle at about 500 rpm which seemed a little lower than usual.

So my question is - is this normal? Am I expecting too much to have all this stuff on at idle and not expect a drain? I didn't notice any issues like this with the previous alternator, but thats not to say it never happened, maybe I just didnt see it.

I am fairly sure that this gauge never moved much before replacing the alternator and I don't want to just put in a new battery without investigating. The battery in-situ looks old and battered and has been in since I bought it in Jan. I did get it and the old alternator tested at the parts store (when it died) and was told the battery was fine.

Any thoughts appreciated. :Wink:

Regards,

B.