question: usb charger adapters

[miltk]

i was wondering if someone could tell me if the MA # on a usb charger adapter has anysignificance?

on an adapter, you'll see something like "OUTPUT: 5.V 550 MA". they vary a little from adapter to adapter, but for the most part they're all 5V...in the case of my razr maxx, it's 5.1V. but the "MA #" varies greatly from adapter to adapter. on my jawbone it's 550MA, on the maxx it's 750 MA, and on the sony mp3 player adapter it's 850MA.

does this mean it's best not to switch usb adapters on a device? what would happen if i used a 750MA adapter on the jawbone or a 550MA on the mp3 player.

thx

[FoxKat]

i was wondering if someone could tell me if the MA # on a usb charger adapter has anysignificance?

on an adapter, you'll see something like "OUTPUT: 5.V 550 MA". they vary a little from adapter to adapter, but for the most part they're all 5V...in the case of my razr maxx, it's 5.1V. but the "MA #" varies greatly from adapter to adapter. on my jawbone it's 550MA, on the maxx it's 750 MA, and on the sony mp3 player adapter it's 850MA.

does this mean it's best not to switch usb adapters on a device? what would happen if i used a 750MA adapter on the jawbone or a 550MA on the mp3 player.

thx

It is highly recommended not to use third party chargers or chargers for any other devices even if they're from top manufacturers with your new phone. The reason is, the manufacturer of your phone specifies the chargers voltages and amperage to be specific to the battery in the phone itself. Since batteries for cell phones and other devices are different, the charging rate for each battery size and type must be specific to the charger.

The only time that information differs is when using a regulated power source through a device such as the computer laptop or desktop usb port. Since those ports are designed to meet the standard usb protocol, they will always put out a source of clean regulated power at 5 Volts and at MA that falls within the tolerances of your phone.

Sent from my DROID RAZR using DroidForums

[doublejack]

It is highly recommended not to use third party chargers or chargers for any other devices even if they're from top manufacturers with your new phone. The reason is, the manufacturer of your phone specifies the chargers voltages and amperage to be specific to the battery in the phone itself. Since batteries for cell phones and other devices are different, the charging rate for each battery size and type must be specific to the charger.

The only time that information differs is when using a regulated power source through a device such as the computer laptop or desktop usb port. Since those ports are designed to meet the standard usb protocol, they will always put out a source of clean regulated power at 5 Volts and at MA that falls within the tolerances of your phone.

Sent from my DROID RAZR using DroidForums

I realize this post is more than a month old, but I feel it necessary to speak up and correct some inaccurate info. I think you are just unfamiliar with how smartphones recharge.

Generally speaking with Lithium-ion batteries, the recharging rule is not to exceed the rated capacity of the battery by more than 50%. So for example a stock Motorola Droid battery (BP6x) is rated at 1300mah. That means in theory it could be recharged at a rate up to 1950mah. That's a modest smartphone battery in terms of capacity, and yet the maximum theoretical recharging rate is well above the amperage provided by basically all microUSB compatible chargers.

However, beyond that each battery has a controller chip integrated within it that will prevent overcharging. That is what ultimately determines the draw, not the output of the charger. Think of a charger as a power source, like the outlets on your wall at home. Your TV is on a 15 amp circuit most likely, but it isn't drawing 15 amps. It draws just a fraction of that because that's all it needs to operate.

In the same way, a smartphone battery will only draw whatever current it is designed for. If your charger can provide more amperage, great! If it provides less it'll still work, charging will just take longer.

That's the beauty of microUSB phones. As long as they're getting 5V, they'll put a charge on the battery.

I have an original droid that's been in use more than 2 years now. I use chargers meant for various blackberry devices, a generic car charger, and anything and everything else that I can plug into for power. There's no risk of harm as long as the protection circuit within the battery pack is functioning.