Usage: It is on all day in the family room on AC power with the battery installed. Primarily used for email, news, weather & some surfing. It is on battery only for up to an hour at a time.
My power light & red-orange battery light started flashing again with power going to 0% quickly unplugged & 100% when it was plugged in. Then it continued to flash while plugged in. It booted fine without a battery, when I installed the battery it gave the unrecognized battery message F1 to continue. Various combinations of this worked 3 months ago when it did the same flashing.
The solution this time was to let it sit overnight & boot with the battery only the next morning. I let it set at 0% battery over 2 hours before it finally depleted the battery & shut down. It charged up OK without the flashing lights & has worked for 2 days.
I guess there is still some life for my Mini 9.