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Dealing With Android Battery Limitations

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 ….

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8 Responses to “Dealing With Android Battery Limitations”

  1. 1 Rich Owings

    My experience has been that the battery will drain very quickly if you leave phone service on in an area with poor cell reception.

  2. 2 leszekp

    I’ve heard that from other people as well. Reception is pretty poor at my house, though, and that hasn’t been a problem. But the Droid X dials back on power to the cellular antenna when it has a good network connection (as it does at my house), and that may be why I didn’t see a drain. I’ll try turning off WiFi and leaving 3G running, and see if those results are worse.

  3. 3 mikeb

    I’ve had the Moto Droid since January 2010. Defintiely the best phone I’ve ever had. Here’s what I have learned about power management:

    There is an excellent stock widget called ‘Power Control Bar’ that puts on/off buttons for GPS, Bluetooth, WiFi, Sync, and Brightness. The brightness button isn’t on-off, but allows three taps: 100% 50% and 35% brightness.

    Here’s a pic of what it looks like:

    This widget is a lifesaver when it comes to power management. If you place it on your default homescreen, you can easily manage your power consumption.

    Recently, I have found turning off the Sync has greatly improved my battery life as well, which makes sense in my case, considering my phone was syncing up with 5 gmails addresses, a facebook account, twitter, Android market, and who knows what else. I’ve rearranged how I read email to set times or when I want to, rather than everytime an email pops in.

    And, really that’s what it comes down to- how you manage your power is entirely dependent on you operate your phone. Its like dieting, if you want it to work, you can’t just take a pill, you have to change your lifestyle.

    Ultimately, the biggest draw is always going to be your screen. I’ve found the on-off button to be my biggest asset when it comes to battery life. And Froyo does something previous versions didn’t: when you turn it back on, your screen will fade in, instead of just ON. This is one of the minor improvements Froyo brings to extend your battery life.

    Other apps that will help:
    • Advanced Task Killer: This app does a great job of killing background apps that combined can be a huge power draw.
    • Battery Snap: This app will track your battery input and output over time and provide statistical data. This can help better manage the way you use the battery. At the very least, you can get a good picture of your battery use over time.

    Also, a word about charging the battery:

    Cellphone batteries are a quirky animal that can be trained very easily. Ideally, you’ll want to do the following things:
    • only charge the battery when the power is below 20-15%, the lower the better

    • when charging, charge it to 100%

    • try to not let the battery go to 0%, thus turning off the phone. I’m not sure why, but the couple of times this has happened to me, the phone is a little wonky until the next full charge.

    • do not leave the charger plugged in after it has been 100% charged, i.e. leave it in overnight. Typically, the battery should charge to 100% in about 30-45 minutes (i’m not exactly sure), especially if you have all the extras (screen, wifi, gps, etc) turned off.

    • Do not, or try not to, partially charge the battery. if you do infrequent charging, it will play havoc will the battery and your phone. When you can get the battery management and use to something consistent, try to charge it at eh same time each day.

    • These suggestions especially apply to car chargers: don’t just plug it in because you are in the car. Wait until it is low to plug it in, then unplug it when it reaches 100%.

    • Another tip about the car charger, although this is unverified, do not let the phone be connected to the car charger when the car is off. Allegedly, this speeds up the discharge.

    Hope this helps….

  4. 4 leszekp

    Wow! Thanks for all the great tips – much appreciated.

  5. 5 Epicanis

    I’m considering assembling something like a “MintyBoost” charger, but modified to take D-cells, for when I’m going to be away from reliable recharge power for a while.

  6. 6 Bill

    JOOS has a very interesting solar “battery” coming out. While other solar chargers seem a bit anemic, this one seems to have some punch.

    Their website:

    Wired review:


  7. 7 John

    What about using an external bluetooth gps? Moreover the gps unit can be put in a place with a good sky view (top of the backpack, …)

  8. 8 leszekp

    Second comment I’ve gotten today about Bluetooth GPS :). There’s no built-in support for Bluetooth GPS, but there are several apps already that include support for it; I’ll be covering some of those very soon. And I plan to do a battery drain and accuracy comparison tests between built-in and Bluetooth GPS soon. The former is easy, the latter may be tricky. The sun is fairly quiet now, so the Bluetooth’s WAAS won’t be as helpful in improving accuracy as it will be in a few years when the sun is more active. I’ll have to monitor the kp proton flux from the sun, do one test when the sun is quiet, then do another when the sun is active, and see if I can spot a difference.

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