I myself have encountered slow charging (>6hrs) on my LG Optimus G Pro.
After some time, I found that it's because when I plug in at the microusb end of my original LG wall charging plug/cable (output 1.2A) to my phone, it was not fully connected (and it was definitely connected though it was charging slowly).
Therefore, please make sure to push the microusb cable all the way in or push it and pull out and push it in again to clear any bad contacts.
Next, it is important to monitor the charging current level. Download the android app Android Tuner Free app.
In the app, goto Battery Manager->Status tab/Battery Charging Flow or the History Tab. Check the settings to enable battery monitoring all the time to get good battery info.
During charging, the charging amount should be around +850mA (higher would be better but mine is within this range)
During when my cable was not plugged in properly, I noticed that the charging current is only at around +350mA.
If the charging current is negative value, then it is discharging and not charging at all.
The original LG battery is rated at 3140mAh.
Therefore charging at 850mA would mean 3.7hrs from 0% to 100%.
Therefore charging at 350mA would mean 8.9hrs from 0% to 100%.
I used to charge at around 400mA and would take 6.5hrs from 15% to 100%.
Note:
1) To improve your battery life, I also use Deep Sleep Battery Saver. And I found that after 36hrs battery level dropped to 50% from 100%.
My usage mostly in terms of internet surfing, whatsapping, texting (sms), camera, news apps, bus arrival time app.
2) Of course, i turned off all automatic syncing eg emails or Facebook,etc. I only do manual sync.
After some time, I found that it's because when I plug in at the microusb end of my original LG wall charging plug/cable (output 1.2A) to my phone, it was not fully connected (and it was definitely connected though it was charging slowly).
Therefore, please make sure to push the microusb cable all the way in or push it and pull out and push it in again to clear any bad contacts.
Next, it is important to monitor the charging current level. Download the android app Android Tuner Free app.
In the app, goto Battery Manager->Status tab/Battery Charging Flow or the History Tab. Check the settings to enable battery monitoring all the time to get good battery info.
During charging, the charging amount should be around +850mA (higher would be better but mine is within this range)
During when my cable was not plugged in properly, I noticed that the charging current is only at around +350mA.
If the charging current is negative value, then it is discharging and not charging at all.
The original LG battery is rated at 3140mAh.
Therefore charging at 850mA would mean 3.7hrs from 0% to 100%.
Therefore charging at 350mA would mean 8.9hrs from 0% to 100%.
I used to charge at around 400mA and would take 6.5hrs from 15% to 100%.
Note:
1) To improve your battery life, I also use Deep Sleep Battery Saver. And I found that after 36hrs battery level dropped to 50% from 100%.
My usage mostly in terms of internet surfing, whatsapping, texting (sms), camera, news apps, bus arrival time app.
2) Of course, i turned off all automatic syncing eg emails or Facebook,etc. I only do manual sync.
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