Engine battery fail
I've got a 5.4 L gas 2001. Uses a group 65 battery. I had one that leaked; it was pretty old so just replaced it a few weeks ago with a nice Odyssey. Put it in, did a few local trips over those weeks; everything seemed OK.
I just started a trip north from Oakland. Again, started OK, didn't notice voltage meter though. Got gas at about 30 mi; OK. Stopped at rest stop at about 65 mi; OK.
Then at about 140 mi I stopped for a late lunch; maybe 45 min. Came out; no start. Not even a solenoid click. The alarm goes nuts (which it does when battery fails) so dealt with that. Got my multimeter on the battery and it seemed to go from 12.8 to about 4.8. Then back again. I'd try to start; nothing. Aargh.
Walked to WalMart. Bought new battery and put it in. Drove home. Put multimeter on the cig plug, and OBD scanner in. OBD would fluctuate from 13.5 to 14; multimeter showed a pretty consistent 13.92, or a bit higher if I turned off lights. Seems high to me, but it shouldn't have broiled a new battery. Not sure exactly where the OBD gets voltage either.
I get home, turn off van in street. Go to start it five minutes later, nothing. Multimeter shows 12.8 though. Then I notice negative terminal is loose. Now I did, mind you, slap that battery from WalMart in pretty quick, but even at home I have trouble tightening on the neg terminal (past experience has taught me sometimes they don't fit as well from battery to battery; wish I had side terminals).
That got me wondering if it was loose on the Odyssey as well, but I don't see how that could explain a 5v reading on the multimeter. Seems it would be 12ish or nothing. When I got home it was back to 12.8; I put a light load on it to see if it will handle that for a while.
Any idea what's going on? Did I just get a dud Odyssey, and then an installer error on the loose terminal? could a loose terminal explain the Odyssey problem?
2001 Ford E250 Sportsmobile with Salem-Kroger 4x4 conversion