Monitor version 1.0 is now available for free download in Ovi Store. As announced in the
previous blog post, Battery Monitor provides a detailed indicator for remaining
battery level with usage time and charging time estimates. Battery level
monitoring and usage time estimates are supported in all Nokia Symbian devices
with touch screen. Widget mini view is available in devices that support
homescreen functionality. Remaining charging time estimator is not yet supported
in all the latest device models, like Nokia C7-00 and C6-01, but it will be in the
future releases. If not supported, the widget will show only “charging” text
instead of time estimation.
In order to
estimate remaining charging time, every device model battery charging profile
needs to be measured in the lab and fitted to a mathematical model. Benefit of
this approach is that it can provide really accurate estimates. Figure 1 shows
estimate from a model compared to actual charging time in Nokia N8.
Figure 1: Remaining recharging time model estimate (in seconds) vs. actual charging time for Nokia N8. Source: Nokia Research Center.
Monitor uses real battery voltage and current measurements for making the
estimates. This allows for much more accurate estimates than the information
available in the current Symbian HW Resource Manager API, which only provides
the same information as the UI battery bars (from 0 to 7). API used for reading
voltage and current is the same as used by Nokia Energy Profiler
application. Because of this, Energy Profiler cannot be used at the same time
with Battery Monitor.
Accuracy of estimations will improve over time as more measurement data is gathered. Especially the overall active usage time estimation requires several days of data. Best accuracy is achieved when there are little variations in daily usage patterns. Accuracy can also depend on external conditions like network strength variations. Data gathering in the background will increase device standby power consumption by less than 0.25 mW. This doesn’t have significant impact on device usage times.
post showed screenshots with white background colour. As mentioned in earlier
blog posts, this is not energy efficient in devices with OLED displays such
as Nokia N8. For this reason, Nokia Battery Monitor will support also black
colour theme as shown in Figure 2.
Figure 2: Screen shots of black (default) colour theme of Nokia Battery Monitor.
Updated version 1.1 will be released in December/January. This will include charging time estimator support for all the latest Symbian^3 devices and improves accuracy of the
existing algorithms. Major UI update and new features (version 2.0) are also
under planning for 2011. We appreciate all the feedback and comments sent to firstname.lastname@example.org and would
love to hear more. Thanks, and have fun with the first release!