Batt light

I haven't had time to trouble-shoot, and it was dark by the time i got home.
Does any-one have advice on this fault?
The battery was down, as I don't drive the van much. After about a half hour drive, I floored the van, it accelerated well, but I caught a flicker on the dash. It drove fine. I tried hard aceleration again, and I saw the Battery Light flash momentarily. It ran fine, and the dash voltmeter said around 14.2 maybe 14.4 V.
I had no trouble on the way home, but I'd rather have a small problem than wait for a big one.
The fan belt is only about 5,000 Km old, so it should be good. And the tensioner was good, last time I looked. At idle, the voltage stayed up when i turned on/ off the lights, however, at idle for around a minute, the dash guage read about 13.8 or so. It had been about a month since I drove it, maybe corrosion on the slip rings?
Ideas?
Thanks

sounds about right with voltage, just as long as when all acc are turned on you should still draw 13 or so volts fromt he altenator.
with the battery light comming on when you floor it it may be your alternator cant keep up and it is ont he way out
but if it was me just drive it till it wears out
scott
ps a 14 volt charge with no acc on is ok , thats what i have

clean the battery terminals, and make sure the cable connections are tight.

As a related followup to the original question.

I just replaced an old battery with a brand new one. The battery light now stays on continuously and the dashboard voltmeter is reading about 10volts

time for a new altenator no question about it
enjoy
scott

I think I may have found the fault. I took the battery out to check it, and found a shorted cell, according to my fancy computerized battery charger.It was down to 10% charge, and it isn't coming up. I'm surprised it started well.
Curious, I bought this van used, but it had a Sears Die-Hard in it. So it's gone thru the original, and a 2nd battery, and it will be on it's 3rd battery. It's only a '97 van.