I had an Atrix 4G, but returned it a couple weeks ago. While I had it I bought a car charger on eBay for cheap. It worked fine with the Atrix.
However, now I have moved to T-Mobile and have a used MyTouch 3G. Since I bought it used, not from T-Mobile, I have no insurance or warranty. Therefore, I am a bit cautious about plugging it into the car charger.
My thinking is that the car charger must be providing the same current as a standard USB port on a computer. I can charge the MyTouch 3G off the USB port on my computer just fine, so I assume the voltage would be the same. But I thought I'd ask here before frying my new (used) phone.
Not all car chargers output the same current levels. The amperage should be written on the charger. Computer USB ports charge at 500mA as do most car USB chargers. However, you can find car chargers rated for higher current. Typically, these higher-current chargers are made for specific models but work with most phones; the catch is that if it's not made for your phone, it doesn't give you the full current. But it is safe to use. A higher current charges faster.
For power-intensive apps like navigation, the power consumed by the phone is often greater than what a 500mA charger can provide. In this case, you'll want to look for a 1000mA (1A) or higher charger made for your phone.
Charging faster means more heat is generated, and Li-Ion batteries are very sensitive to heat. So if you care about the longevity of your battery, try to charge at lower current whenever convenient.
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My thinking is that the car charger must be providing the same current as a standard USB port on a computer. I can charge the MyTouch 3G off the USB port on my computer just fine, so I assume the voltage would be the same.
However, you can find car chargers rated for higher current. Typically, these higher-current chargers are made for specific models but work with most phones;
There's not really any "typically" in this case. There are plenty of generic chargers that supply more than 500mA.
Quote:
Originally Posted by novox77
the catch is that if it's not made for your phone, it doesn't give you the full current.
If it doesn't supply as much current as your device can handle it doesn't give you full current. OEM versus aftermarket isn't really relevant. Check the specs on the charger (as you mentioned).
I have 3 different car chargers and never paid attention to which one I was using, but they always seem to charge much faster than the usb port on my computer. The one I have on me right now came with a bluetooth speakerphone and its 750ma. I don't know what the others are.
If it doesn't supply as much current as your device can handle it doesn't give you full current. OEM versus aftermarket isn't really relevant. Check the specs on the charger (as you mentioned).
The device draws as much current as needed, or as much as it's programmed to accept.
Android phones have two charging modes: trickle (USB) or full (A/C) mode. Trickle will always be 500mA. The device makes the determination based on the voltage on the data pins. Many times, manufacturers program the device to look for a very specific voltage before it allows full A/C mode charging. On my Evo, A/C mode is only engaged when the data pins are shorted. Then it will charge at the max rating of the charger.
Many 1A+ chargers only trigger trickle mode on Android devices (I know from personal experience). You'll want a battery app/widget that indicates which charging mode your device is in to know for sure. Will a generic work with your phone at the max amperage? Maybe. But you're gambling that the charger's data pins are doing what your device is expecting. If it's not, it defaults to the slower charge. Safest bet is to go with the OEM. Otherwise, you will do what I did: buy a bunch of cheapo generics until you find one that actually triggers A/C mode.
I would say I see quite a difference between mains, USB and car charger. Mains will charge my desire pretty quickly, USB quite slowly and my cheap Ebay car charger will only keep the battery steady when using navigation with the screen on. Switching the screen off will allow it to charge. I think that this is pretty standard.
Do all car chargers provide the same current?
