Two days ago I discovered my '91 Volvo 945T won't start, after 3 days of non-use.

I charged the battery some at home, drove around to charge it some more, and then (twice) it stopped dead, in that "the ignition is running off the battery" manner.

The battery is about 7 months old. (Symptoms leading up to replacing the previous battery did *not* include the vehicle electrically running into the ground, merely an old, old battery not starting after much disuse.)

Good news: The second time it starts dying, I coast, barely, into a genuine mechanic's garage, who takes out his charger and plugs it in for an hour.

After that interval, it starts, he gets out the meter, and shows fine voltage at the battery. Then it drops to insufficient, with no change in load--no playing with AC or lights or etc. The low reading was maybe 11v or so; the system wasn't charging the battery. He hits the alternator with a wooden hammer handle, and the voltage reading goes back to fine.

(PS All this for $10, and ending at 6:30pm. Can't beat that!)

After reading other posts on battery drain:

The connections and leads at the alternator seem OK. I want to add a (fused) voltmeter; should I do so at the battery, alternator, or where?

With a fully charged battery and an ammeter in line, I'm getting current readings of under 10mA. This is before playing with fuses for, say, clock and radio and seat heater or seat mover. (Also,I haven't heard any odd noises from the central locking system, and the power antenna was replaced with a mast years ago.)

Can something short on the alternator which can drain the battery when the vehicle is off and the key is out?

And how difficult is it to rebuild the alternator myself?

Thanx in advance,