Thanks, this morning it was still blinking at 100% and floating above 14v on the charger. I don't think it should be taking *this* long to get up to full charge even on a full discharge (it's been 80-90+ hours on the charger now!) I did a quick test, unplugged the charger and measured the voltage after a few minutes. Voltage dropped down to 12.92v and seemed to be decreasing by .01v every 15-30 seconds. I'm wondering if it will drop all the way back down to virtually nothing if I let it sit the whole day. When it's not charging and is just sitting plugged in, it sounds like it should be reading a consistent 13.5-13.8v and not dropping in voltage like what I observed. Any ideas?
EDIT: hmm, reading around it sounds like 12.6v is the magic number. So maybe I outta unplug the charger tonight and let it sit for longer to see if it finally 'rests' around 12.6v. Then I'll know it's in good shape.
Yes, 12.6V is a good fully charged OCV (open circuit voltage) for a 6 cell lead acid battery. My guess is that the charge took so long because the charger stayed in the desulfation mode for so long; it needed to since the battery voltage was so low.
Just sitting on the charger with the charger maintaining a float voltage should give you a voltage in the mid 13V range.
A quick check I mentioned up thread is to turn on the lights in the car for about half a minute; this will remove the surface charge on the battery. This should get you down around 12.6V, maybe a few tenths of a volt lower.
If the battery voltage is a lot lower in the morning after sitting overnight with no load and no float charger (say, 11.n volts) then you probably have a damaged battery. The deep discharge probably created an internal short in the battery somewhere which is making it discharge quickly with no external load.