Sign in with
Sign up | Sign in
Your question

USB charger/power tech question

Last response: in Cell Phones & Smartphones
October 17, 2010 4:12:53 PM

I recently acquired a smart phone, but I suppose this question applies to USB power and specifically chargers of all types.

Can anyone tell me, or point me to a good guide that breaks down information about general compatibility for charging devices that use USB ports for this purpose?

Specifically I have a number of chargers that came with devices, and most seem to put out 5v but a varying amount of mA ratings. So in general I'm wondering what can be used to charge what safely. I believe my phone came with a 850mA charger (at 5v), so would it be save to use one that is 1000mA? What about 500mA? Also my blutooth headset came with a charger as well, but I believe it was significantly lower like 80mA or some such. Additionally the phone came with a car charger, and i'm not even sure what the mA rating on it is, but it has a 2nd port for more devices to charge at once.

So what happens if I plug my blutooth headset device into one of these larger chargers, or the car multi charger? Does it just take what it needs and ignore the rest? or will the higher mA cook it? I looked online for quite awhile and I couldn't find very much useful information on the topic, only anecdotal comments that I didn't find to be of much use.

Also i've noticed that often many of these products don't even seem to specify their mA ratings on shopping sites when you are looking for car chargers ect, and it doesn't help that my headset (Jabra VBT3050) doesn't seem to have an existing manual anywhere.

Anyhow just looking for some clarity on the topic, so I can make more informed decisions about what chargers to use to charge what devices, without damaging any of the devices. Thanks in advance for any information.

EDIT/UPDATE: I found the charger for my Jabra headset to be 5v at 180mA (just adding the detail not that it changes my question really)
September 2, 2012 3:58:58 PM

I think using a charger with higher ampere rating should not harm a device, because the device will only draw the required amps, using a charger with lower rating may cause malfunction. a note of caution however; The small usb ports are of various types ( Mini, micro etc. see details at
using a charger with a different type port may cause problem, luckily most of the ports in new devices are of 'micro usb' type and are compatible.
September 2, 2012 5:51:42 PM

!!! Add More Battery Life to Your SmartPhone or Any Other Mobile Device !!!
Get the RECHARGEABLE Amity Battery Extender

On Sale Now

It will quickly charge your iPhone or Android Phone up to 3x.
It may also charge your Nexus 7, iPad, and Digital Camera

- Super Compatibility: Phones, Bluetooth, GPS, GoPro
- 3 Colors to Match Your Personality
- Got Blessed for Certification
- Received Nothing But Rave Reviews
- Portable: 3.66" x 1.69" x .87"; FCC, CE, RoHS Compliant

Click on the link just to check it out ...