Originally Posted by Blossom
7 days is that with WiFi off? My K3 I charge every 45 days but that's with WiFi off. My K4 last up two weeks on a single charge and that's with heavy use.
In early 2011 I was reading exclusively on the Kindle Keyboard WiFi with WiFi on all the time. I was averaging 26 days until the 15% signal was given.
In early 2012 I was using mostly the Kindle Fire 1st Generation with WiFi on all the time and averaging 5 hours over 3 days using GSam Battery Monitor to get the precise numbers.
Now using the Kindle Fire HD 7" 32 Gb I was getting 5 hours and 32 minutes down to the 19% level over 5 days using GSam Battery Monitor to get precise numbers. However, my last cycle I went down to the 8% level over 4 days and got 6 hours and 53 minutes.
On the Kindle Paperwhite I used a precise Session Measuring formula for one cycle and got 10 hours and 29 minutes over 7 days. The other cycles lasted for 7 or 8 days before a full charge was required with the battery meter showing near empty.
There is no question the Kindle Keyboard lasted the longest time frame. However, I never did use a precise Session Measuring formula to prove its real time usage.
I had WiFi on all the time for all my units.
It would be interesting to see GSam Monitor results for others on percentage of battery energy reached and time elapsed between cycles.
For the Kindle Keyboard and Paperwhite a specific Session Measuring formula would have to be maintained for every reading session showing start time, end time and Session time with cumulative time used before the full charge was required. Unfortunately, there is nothing like the GSam Battery Monitor for those two models to get precise results.
I maintain a Battery Record Excel Book for all my devices and gadgets. It is fascinating to see how all of them perform with regards to battery usage.
Everyone should take their Lithium batteries down to near zero at least once to get the chemicals mixed properly and to tune the battery monitor. After that one exercise it is not necessary as long as the device is being used regularly.