[peter9477]

Peter,
Have you ever tried to boot up right after plugging in a drained PB?

I missed this until esoRdeR happened to quote and respond to it.

I've done full discharges (till it shut off) probably close to 50 times by now, on a total of eight different PlayBooks (some just once, but with my original about 30 times).

I think about four times, all with the original and in the early days, I had some difficulty getting it to restart until I'd left it on the charger for maybe 20 minutes. That was around the same time when others were reporting similar issues, so I was not too surprised when it happened, and merely followed their lead by being patient.

I think, based on what I've seen, I'd say it was a glitch with the early versions of the OS, and not something I'd expect to see in more recent builds, but that's speculation. I wouldn't stick to that theory if someone can provide reliable reports of more recent occurrences of this problem.

Aside from that temporary problem, which I haven't seen lately (since probably June), I've noticed no ill effects or complications due to full discharges. When they're empty, I put them on the charger, wait a minute or so for the periodically flashing LED, then power them back on, launch Battery Guru, and all is well.

[kill_9]

The Battery Guru application shows that over the early life of the battery the health percentage can fluctuate. Until the tablet has been repeatedly fully discharged and automatically shuts itself down followed by a full recharge, the calibration cannot be taken as accurate.

Each month I allow the tablet to completely drain to the point of shutdown. Throughout the month the tablet is on the charger well before reaching 0%. The health of the battery has improved and the readings by both the device and Battery Guru represent a more accurate picture of the charge state of the battery. The OP need not fear fully draining the battery.