[eric_bb]

I just noticed this. I usually charge my Q10 before going to bed and get it off the charger when I wake up. Last night, I plugged it in at 30%. About two hours later, a text came in and I noticed the battery indicator saying it was full. Since I was doing something then, I left it plugged in. After two more hours, I got it off the charger and noticed that the battery was 95%. Is this normal? Does the charger stop supplying power when the battery reaches 100% and does the battery start to drain even if it's still plugged in? Faulty battery, maybe?

[SmellWhole]

I remember reading somewhere that it's normal. I think it's called "parasitic drain." You can look for more of an explanation for it on the "Battery University" website.

The best thing to do is leave your Q10 plugged in all night as you have been doing. If your battery is low, and you can't charge all night, at least try to charge it for 3-4 hours. If you just throw it on the charger for an hour, the battery gauge might indicate full, but it's really not; once you take it off the charger it will drop fast. For a quality full charge it takes hours.

[eric_bb]

But it was 4 hours total. First two hours, it said full. Left it charging for two more hours. After unplugging, it said 95% battery.

[SmellWhole]

"If a lithium-ion battery must be left in the charger for operational readiness, some chargers apply a brief topping charge to compensate for the small self-discharge the battery and its protective circuit consume. The charger may kick in when the open-circuit voltage drops to 4.05V/cell and turn off again at a high 4.20V/cell. Chargers made for operational readiness, or standby mode, often let the battery voltage drop to 4.00V/cell and recharge to only 4.05V/cell instead of the full 4.20V/cell. This reduces voltage-related stress and prolongs battery life.

Some portable devices sit in a charge cradle in the on position. The current drawn through the device is called the parasitic load and can distort the charge cycle. Battery manufacturers advise against parasitic load while charging because it induces mini-cycles, but this cannot always be avoided; a laptop connected to the AC main is such a case. The battery is being charged to 4.20V/cell and then discharged by the device. The stress level on the battery is high because the cycles occur at the 4.20V/cell threshold.

A portable device must be turned off during charge. This allows the battery to reach the set threshold voltage unhindered, and enables terminating charge on low current. A parasitic load confuses the charger by depressing the battery voltage and preventing the current in the saturation stage to drop low. A battery may be fully charged, but the prevailing conditions prompt a continued charge. This causes undue battery stress and compromises safety." -- Battery University

It's a trade-off, I guess. I put my Bold on the cradle when I go to sleep. It goes into bedside mode and displays the dim clock. Yes, that's a parasitic load, but I like the clock and the availability of the device should I wake up or get a call or message until ... 2:30 am when my Bold's Auto Off kicks in. Now, the phone is off until 8:30 am or when my alarm sounds, whichever comes first. No parasitic load = a full saturation charge for maximum capacity and optimum runtime.

[eric_bb]

Thanks for posting that. I was just confused with what happened last night because on a previous Q10, I'd leave it to charge overnight and when I unplug in the morning, it says 100%. Which was why the new Q10 (first charge last night) behaved strangely to me.

[SmellWhole]

Thanks for posting that. I was just confused with what happened last night because on a previous Q10, I'd leave it to charge overnight and when I unplug in the morning, it says 100%. Which was why the new Q10 (first charge last night) behaved strangely to me.

Absent further radical strangeness I don't think you should be overly concerned about it. As seen in just that small excerpt, battery technology is extremely complex. Keep an eye on it, and if really crazy stuff starts happening or usability issues arise you might just need a new battery. (See if it happens again or keeps happening.)

[Diogo Cardoso]

Thank you for the explanation, I realised something with the new os 10.2.1.2102 my Z10 when goes off because of the low battery and when I charge it, a few minutes the phone turns on when I would like to stay off to charge like you said. It happens to everybody or I just have to wait to turn it off again?

Posted via CB10

[SmellWhole]

I wouldn't worry about it so much, Diogo. I f you want it to be off while it's charging just turn it off either before it dies or after it turns back on (if it happens to shut off and turn on by itself).