Apple Video Ipod - Battery Life analysis HDD vs. CF
Results
The iPod that was tested had been fitted with the new brighter 5.5G LCD, so I added extra data to show the effects of the back-light brightness setting. Also the battery on this iPod had been replaced couple of months back, so it is still very fresh and should provide consistent run times. These results will not relate to the 5.5g Ipod as it appears that is either running different chipset or power saving techniques which in theory will produce longer run-times than shown here.
Looking at the electrical current draw table, you notice a few interesting things. Playing video or audio does not change the amount of current required, which is very surprising as you would have expected higher drain for video decoding. The base current drawn is around 30mA without the back-light on, which is very good. The main draw after the hard drive is the back-light and at nearly 100mA at maximum brightness, you can see how the back-light setting will have a big effect on battery life.
You will notice the compact flash version suffers from an increase in current during the spin-up and read cycle, this is probably down to a) the CF card being initialized, b) the ipod activating the i/o systems, like the storage interface and processor.
As was to be expected the Hard drive needs up to 4 times the current required by the compact flash card. In my tests during high quality video playback the drive was spun up and read every 90 seconds, and the whole spin-up, read, and spin-down sequence would take about 4 seconds. Considering the battery is about 480maH in capacity the spin-up sequence is quite a heavy load.
For someone who likes to play with there ipod i.e. constantly scrolling through songs, fast forwarding video and music - making the hard drive spin up and down quite often will see amazing increase in battery life by switching to compact flash storage.
Lets move on to the battery life tests.
The results surprised me here, I was expecting video playback to have the biggest increase. However this is not the case and this is due to the fact the back-light is on all the time being a major current draw tends to level out the difference between the HDD and CF over long periods.
Video playback with the CF came in at 5hrs 49mins which is an amazing 1hrs 25mins increase over the hard drive, and if you can live with reducing the back-light a few notches I can imagine breaking the 7hr barrier.
Audio playback recorded the biggest increase in terms of actual usage time and as a percentage increase. As the back-light was off the battle was between the current draw of the storage mediums. The Compact Flash came in at 15hrs 20mins of playback and a very impressive increase of 42% equating to an extra 4hrs 30mins over the Hard Drive.
Conclusion
While the test results showed pretty good increases by the compact flash camp, I still think in real life usage the increases will be even more spectacular. The tests demonstrated continuous play, with no stopping / pausing / switching on and off, these increase current demand as the hard drive needs to be activated. These things are what saps power and with the compact flash installed these things do not draw anymore current than the back-light.
Video performance of the compact flash will enable you to fit another film in on a flight, on the audio front you can fit an extra 4 hours flight.
How the Video Ipod’s should have performed from the factory……
- Related Posts
