# Will plugging my camera into the computer charge its battery? **URL:** \ **Category:** Factual Questions\ **Created:** [January 31, 2006, 7:04pm UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391 "2006-01-31T19:04:32Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![she\_sells\_sea\_snails](https://avatars.discourse-cdn.com/v4/letter/s/ea5d25/32.png) [@she\_sells\_sea\_snails](https://boards.straightdope.com/u/she_sells_sea_snails)\ **Post date:** [January 31, 2006, 7:04pm UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/1 "2006-01-31T19:04:32Z")
I think it does but a friend says this is impossible. When the camera is plugged into the computer it turns itself on automatically, so I guess it doesn’t drain the batteries (4 AAA’s) When I power off the computer the batteries just kick in. Seems to me when the computer is on there would be 6v swimming around the power input line, and it would be in parallel to the batteries and charge them. Right? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 31, 2006, 7:08pm UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/2 "2006-01-31T19:08:50Z")
Some do, some don’t. The USB interface supplies 5 VDC at a max of 100 milliamps (more, if you use a powered hub). This is certainly more than sufficient to trickle charge batteries. Whether yours does or not depends on which camera it is. If you post the make and model number, I or someone else may be able to find out for you. ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [January 31, 2006, 7:10pm UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/3 "2006-01-31T19:10:47Z")
what kind of batteries are we talking about?? Regular alkalines?? If so, I’d tend to side with your friend in this case. USB ports do indeed include a power feed, and many devices (my MP3 player and some palmpilots I own for example) are designed to carry this power source down the cable and use them to recharge the internal lithion batteries. However, a camera running off of alkalines would have neither rechargeable batteries or charging hardware inside. I suspect that something else may be going on… many kinds of batteries show higher if they’ve been given a chance to ‘rest’ rather than continuously discharging. If your camera is running off the USB power, it is giving the batteries a chance to rest. That’s just a WAG though. hi qed. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [January 31, 2006, 7:15pm UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/4 "2006-01-31T19:15:25Z")
My camera is old; an Olympus D-510 Zoom. When it is plugged into the computer via the USB port the batteries discharge as if the camera were turned on – even if it is not. ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [February 1, 2006, 12:57am UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/5 "2006-02-01T00:57:22Z")
Digital camera engineer chiming in, USB has a current limitation of 500ma, I doubt that would be sufficient to both run the camera and charge it, I’ve heard of cameras that do either (it’s either on and transferring data, or off and charging off USB) but I’ve never heard of cameras that do both. It’s not impossible, but either you would draw too much current from USB (which is certainly possible, but might be dangerous to some equipment) or you need one heck of an energy efficient camera. ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [February 1, 2006, 12:59am UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/6 "2006-02-01T00:59:12Z")
I’m talking about cameras that are capable of charging their batteries in the first place, which is pretty rare IMO, usually you need an external charger. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [February 1, 2006, 1:41am UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/7 "2006-02-01T01:41:11Z")
Camera’s normaly use their power system to run the camera interface. The USB is just data flow. I won’t say you can’t find a camera that does what you want. Look up your model since you want to know about your camera. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [February 1, 2006, 2:54am UTC](https://boards.straightdope.com/t/will-plugging-my-camera-into-the-computer-charge-its-battery/342391/8 "2006-02-01T02:54:05Z")
> [@Johnny L.A.](#): > > My camera is old; an Olympus D-510 Zoom. When it is plugged into the computer via the USB port the batteries discharge as if the camera were turned on – even if it is not. I suspect that it is on. It probably turns itself on when it detects a USB port active to some degree.