Battery Discharge
 

I had this happen to me several times when I had 2 bars on battery life, left the cover on and didn't use for a couple of days. When I did go to use it the battery was completely drained. Does the battery drain irregularless if the cover is on or not?

Secondly, if I just leave it plugged in and use it will it damage the battery when I disconnect it from the power supply?

To answer your question: yes, the battery is discharged at a regular rate regardless of whether the cover is on or off. It will be discharged at a much quicker rate if you leave an audio file paused or even hit stop and leave the audio player application open. The only way to stop it from discharging the battery is to hit the power button and select Switch Off. You should have about 170 hours of standby time (assuming a new battery) after charging the 770, which comes out to a week. Leaving it plugged in will not damage the battery although the battery will slowly self-discharge over time. I'm not sure how long it will take, but you could conceivably end up with a dead battery if you left it on the charger long enough. Lithium batteries are never trickle-charged, and once they're charged they are effectively disconnected until the next time you unplug and plug back in.

Larry

Some applications appear to be less than well-behaved: I had to remove Horizon from my 770 because it was the apparent cause of unwanted battery-drains.

Of course, the fact that I could not make it do anything useful might have had some inpact on the decision to flush...

According to the manual, the battery could become damaged if left on the charger for long periods after it has been fully charged.

Any battery will continue to receive current as long as it is connected. Some recharger units have circuitry that detects a fully charged battery, and the recharger itself switches off. Given what the manual says, I assume the 770 does not have this function.

well this stinks. considering i leave my 770 on the charger almost all the time ....

I honestly believe that there was some confusion on the part of the tech writer who authored the manual with older battery chemistries (NiMh in particular). The only other (remote) possibility is that the battery might self-discharge to the point it is damaged. That being said, lithium ion batteries are never trickle charged. It's crucial that they not be over-charged as they become damaged and can start a fire. Please see:

http://www.batteryuniversity.com/parttwo-37.htm "...lithium-ion cannot absorb overcharge and no trickle charge is applied on full charge."

http://www.powerstream.com/li.htm "It is important to note that trickle charging is not acceptable for lithium batteries. The Li-ion chemistry cannot accept an overcharge without causing damage to the cell, possibly plating out lithium metal and becoming hazardous."

And finally for info on fires/accidents: http://chemistry.about.com/b/a/244589.htm

Larry

yeah i had the same problem about the battery draining. i thought i had a defective unit or turned the unit off wrong. for some reason it seem to do this when i have the cover on it.
since then i recharge it dand left the cover on and no drain. ill try a full charge, unit turned off, and cover on and see if it drains it

I agree that it was probably a mistake by by the tech writer. Perhaps it could be tested before/ after charge with a voltage meter under load.