In terms of energy usage, cars are very similar to our smartphones. For example, an Audi S4 has a powerful 352HP V8 engine. It’s a fun car to drive, and provides all the features you might be looking for in a car. However, the 352HP engine comes at a price; it sucks gas like nobody’s business, and like the powerful Thunderbolt requires a source of energy to function. The S4’s source of energy is stored in a 14-gallon gas tank. If you push the car to it’s full potential – it will get approximately 10 miles per gallon. The S4's baby brother, the A4, has a less powerful 4 cylinder engine, but averages twice the number of miles per gallon with the same size gas tank. Smartphone’s aren’t any different.
That said here are some of the most common items (based on my unscientific tests of various smartphone’s) that are the highest consumers of battery life. Most are manageable from a user perspective, some are not. Just remember there's a trade off between performance/features and the amount of power you’re willing to devote to each.
- 3G/4G connectivity/activity -- web browsing and apps that use the network regularly for updates (Facebook, RSS readers, Friendstream, etc).
- See those little data arrows at the top of your screen? When they are light grey in color, network utilization is zero. When they are solid white, network usage is occurring. If they are constantly white (as they would be when streaming radio for example) battery consumption is at it’s highest.
- Regardless of backlight settings, the screen is still a major power consumer. Having said that, slight changes in backlight settings can make a dramatic difference in battery consumption. I would recommend avoiding the very brightest setting. My preferred setting is to let Android manage screen brightness, while others have manually enforced a constant low to medium brightness level.
- Bluetooth sucks down power. I’ve experienced this on every phone I’ve ever used. Smartphones are no exception. Turn it off when not in use.
- GPS:
- Like Bluetooth, it consume large amounts of energy while updating coordinates and communicating with satellites. Combined with turn-by-turn directions and an always-on backlight, in order to see the maps guiding your way, you’re pushing battery consumption to the limits. I often read posts from people who are using the Thunderbolt as a full time GPS device in the car.
- One common complaint from users is that USB chargers are only maintaining the current battery level – or worse – when GPS is in use. Since a phone limits USB host connections to 500mAh of power input, this is a good indicator of how much GPS consumes. In other words, 500mAh of continuous power to the phone is not enough to charge and take advantage of GPS/turn by turn directions at the same time.
- Whether 3G/4G, or WiFi, weak signal strength can affect battery life.
