Monday’s post confirmed the common wisdom that GPS use on an Android unit is a serious drain on the battery, and is can be a significant limiting factor in how long you can use your Android unit out in the field for acquiring geographic data. So the question is, are there ways to work around this problem. With the Android unit itself, there are limited options, most of which aren’t terribly helpful:
- Keep GPS use as limited as possible. But this means exiting programs using GPS, and then starting them up again as needed, with a delay in position acquisition as GPS reacquires satellites. Not very practical
- Keep the screen brightness as low as possible, and turn off the screen when it’s not needed. This can help, but there’s likely going to be times when this isn’t practical.
- If you’re in an area with no cellular or WiFi connectivity, you can turn those off and save a bit of power. But from the table in Monday’s post, it’s clear this helps so little that it’s almost not worth bothering with.
So the only real solution is to look at ways at supplying power to your Android unit to recharge/supplement the battery when you’re out in the field.
- Get a charger unit that works with the 12V cigarette lighter in your car. Plugging your phone into a charger whenever you can will extend the number of hours in a day that it will keep working. If you’ve got a USB cable you can use for charging, a USB car power adapter like this one from DealExtreme is dirt-cheap. A dedicated charger with the right adapter plug can cost $15 in a retail store, but you can find them for less than $4 shipped on eBay; just search for your Android unit name and charger, and you should get lots of hits.
- Portable USB power supplies. These have a rechargeable battery and a USB power plug for output; if you need a spare USB cable, eBay has those cheap as well. These power supplies can run from $20 up, depending on how much battery capacity they come with. But you should check the specs on these very carefully to make sure they’ll work with your phone. Read the power specs on the charger that came with your phone, and find out what the output current capacity is (typically given in amps or milliamps, “mA”). The power supply you buy should be capable of putting out at least that much current (more isn’t a problem); if it isn’t, it may not be able to charge your phone, much less keep it running. Take it from someone who didn’t read the specs closely enough on the power supply he bought :(. This can be an expensive but useful option, especially if you have other hardware (e.g. GPS units) that can run off one of these. From the comments on yesterday’s post comes a recommendation for a charger from Amzer. It’s expensive at $90, but it’s listed as compatible with most smartphones (including the Droid X), and has a built-in solar charger that could make it a good option for those times when an electrical outlet is nowhere to be found.
- Spare replacement batteries. If you look for phone batteries for your Android phone at retail, be prepared for sticker shock; a spare OEM battery for my Droid X costs $45. You might try eBay; a pair of batteries for a Droid X is available for less than $10. Don’t know how good they are, and using them can void your warranty.
And hopefully, some GPS manufacturer out there is designing a rugged, waterproof Android-based unit with long battery life that takes standard rechargeable AA cells ….