If it just wasn't charging, then possibly.
Are you sure the alternator is drawing current when not spinning?

Drawing current is most probably a diode gone short circuit (you may be very lucky and find something conductive has gotten in somehow causing the problems, but it's really not that likely).
You're looking at a minimum of £30 for a diode pack (I've never been able to identify/source individual diodes, plus most are spot welded on now), and that's if you can find somebody to supply one.

There's two ways to check the diode pack.
One involves using an oscillscope with the alternator running to see what kind of waveform it's producing, but with modern regulation/ripple suppresion, it's not that reliable.
Other involves stripping the alternator, unsoldering the stator coils, and checking the diodes (there's 9 of them - 6 charge diodes, and 3 field diodes) using a 12v battery and test lamp. It's not unknown for diodes in alternators to go short circuit, as they're driven pretty hard, with minimal cooling (especially when left idling)


What vehicle is it on?