Charging the iPhone while using GPS.

Discussion in 'iPhone Tips, Help and Troubleshooting' started by GogDog, Aug 5, 2008.

  1. GogDog macrumors newbie

    Aug 5, 2008
    Hello all. I searched for an answer to this, and didn't see one, so please excuse me if this has been covered.

    I have an iPhone 3G which I wanted to test out as an all day GPS device while driving in my work van. I have a very new laptop, and I left the iPhone plugged into a USB port on the computer as to allow it to remain charged.

    I used the iPhone all day, using the GPS tracking instead of my usual map book to go from appointment to appointment, and of course, it worked great.

    But towards the end of the day, I noticed that my battery was draining, and even got down to about 25% according to the battery indicator. I switched to a different pair of USB ports on the computer to rule out the possibility that one may be a set of 1.1 ports and the other 2.0, but it continued to drain, even though the iPhone indicated that it was charging, both on the indicator (the electric bolt) and the lock screen (which showed the actual battery charge level while prompting to "Slide to Unlock").

    The only thing I could think of was that, even though it was charging, it couldn't keep up with the power drain. So I exited the Maps app, and opened Scribble as it seemed to be the best bet to not use any power-draining services. Within 20 minutes, my charge level shot back up to 50%.

    So, is the GPS using that much power, or is the phone just not charging while using GPS? Has anyone else had a similar experience?
  2. anthonyb macrumors member

    Aug 14, 2007
    It could be a possibility of the phone using more energy than it can charge.

    One recommendation is possibly see if there is some type of cigarette adapter that will give you more power?
  3. tjespo22 macrumors 6502a


    Jun 27, 2007
    Staten Island NY
    i used mine for a 15hr drive to kentucky and i had it on charge using the usb cig lighter adapter and it worked fine.
  4. GogDog thread starter macrumors newbie

    Aug 5, 2008
    Thanks. Maybe its just not getting much power from the laptop. Could be the inverter powering the computer. I'm sure the sig lighter is an overall better solution anyways.
  5. Nikhil72 macrumors 65816

    Oct 21, 2005
    whoo, I thought it was just me. I noticed this a while back and chalked it up to using too many power-draining radios at once. While driving with GPS, I tend to have music playing in the background over the car sound system from the iPhone's iPod app, have Bluetooth active for phone calls, and use the GPS with tracking enabled for guidance. I noticed that my car charger doesn't actually seem to be charging the device when using all of these; in comparison, if I disable GPS tracking, then charging seems to function. I wasn't sure if it was that my car might not be outputting enough power or something.
  6. macduke macrumors G3


    Jun 27, 2007
    Central U.S.
    I was using the GPS in my car with my girlfriend as the navigator with it plugged into a cigarette adapter as well and it would not charge up until I turned off location services. It made me really mad. My iPhone gets warm when charging, and it gets warm when running the GPS. I wonder if doing both causes too much heat. If that's true then that is pretty sucky on Apple's part. I have had a few issues with my battery being kinda flakey though...with the charge level jumping around. Sometimes it will be in the red and I'll plug it in and it jumps up to being 50-60% charged within seconds. Perhaps my iPhone is just faulty. 10 more days until I'm near an Apple Store...
  7. dizzy13 macrumors 6502

    Jul 9, 2008
    I just did a test of USB vs outlet charging and going from 0% to 100% charge took about 50 mins longer using the USB. Took about 90 mins for outlet and 140 for USB.

    Also, in the car using a cig lighter with the GPS, 3g, and ipod going the phone would show full and charging and full and charging and so on, but never dipped below like 95%.


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