Well well well...I have officially come upon the first problem with this car that's rendered it undriveable.

Two days ago, the car drove perfectly; started up normally, acted normal, and everything. I didn't drive it yesterday (except leaving the left side parking lights on; I park in the street in an area where sideswipes aren't uncommon; also, this hasn't affected anything before). Today, I went out to start the car and nothing. I heard what sounded like across between a buzz and a squeak, which turns out is coming from a black box on the driver's side inner fender almost at the very front of the car. With this, the brake and battery light appear to be on albeit very dimly, the glow plug light appears to not be lighting at all, and the car does absolutely nothing (except the fuel gauge going to 0) when I attempt to start it.

I pulled the battery and took it to Kragen, where they're able to charge and load-test a battery. After about 30 seconds on the charger, it came back with an error saying that the battery is inserviceable. Me being the ornery me I took the battery over to the boat I work on and hooked it up to a 10 amp charger. After almost an hour of the charger needle being pegged (I filled the cells all the way halfway into it, although they weren't that bad to begin with), I took a hydrometer to each cell...and with the charger still going, each one left the hydrometer float in the red, and two of them didn't even budge the float (actually, none of them really did). So, it looks like the battery's dead...

First, what batteries have you all had good luck with? I figure the higher cranking amps, the better, but what size/grouping is the battery supposed to be (the one that's there seemed to be a bit smaller than the battery tray)? Second, is this my real/only problem? What else should I take a look at? The warning light hasn't lit up except as a pre-start check, so I'm guessing the alternator's okay...

Thanks in advance! I assume I shouldn't go over to Albertson's and get a set of AA's OTOH if I do, maybe it's time to change the diesel spark plugs while I'm at it

__________________
2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999