Well, it looks like I may have outright killed the big battery during the last round of discharge/grid charging.
After I grid charged it the first weekend in May, it started back force-charging by the end of the week, along with a negative recal that ended with the check engine, IMA and 12V battery lights coming on.
So I decided to give it another round of discharge and grid charging . . . .
Warning: Do NOT attempt to discharge the IMA battery on Friday evening without setting an alarm, especially if you use twin 200 watt bulbs in the discharger and are prone to falling asleep!
Anyway, I managed to forget I was discharging it, and ran it down to zero volts overnight, which I'm pretty sure effectively killed it. I got it to take a charge that weekend and it charged all the way to 172, but then immediately gave me a recal when I drove it next, followed by the three lights. And it didn't seem to want to rev over 3k . . .
So I flipped the switch on the IMA battery this weekend and for now I'm throwing the 12V on a battery tender nightly just in case it doesn't want to charge the 12V.
The good news is that it seems to have had no effect on my mpg!
The tank started out horribly since it was doing a recal every trip, but this morning after turning off the IMA battery I'm getting really good numbers on the instant readout, and I figure I'll still be able to maintain 70+ mpg tanks unless something changes. With about 75 miles on the tank before I drove it this morning, I managed to go from 64.6 to 70.2 mpg for the tank on the way to work this morning.
I'll keep you guys updated, I'm sure there's more to this story
