I've seen a lot of conflicting information about charger capabilities, charge rates, etc. for the EVO Shift (and other EVO handsets). It even seemed like the OEM charger/cable may be charging the phone a bit quicker than, say, my Motorola charger which is rated at 800mA. So I hooked up a test bed with a 6A bench supply set to 5.1V DC with a multimeter measuring amperage that the phone is drawing.
So far I cannot get the EVO to draw more than 480mA. I've cross-connected the USB Data+ & Data- signals at the power supply end as this is what the OEM charger wall wart does (I 'beeped' those signals out in the charger and they are indeed connected together). Also, the OEM charger does not apply any measurable voltage bias on those two data signals (which is how Apple chargers work). I'm using the OEM USB cable to connect to the phone.
Finally I set up the OEM charger so that I could measure what the charger draws from the wall socket - 51mA (AC) at 114 VAC. That's about 5.8 watts. Sure sounds like it's drawing 1000mA! Grrr.
So I used a USB breakout adapter in-line with the OEM charger and OEM cable. Nope - 480mA. I didn't really think the OEM charger was 100% efficient. So I see no evidence that using a charger that supplies > 500mA results in quicker charging. So far, anyway. My battery level was at about 50% for these tests.
Also, there are threads discussing what the EVO does once that green light comes on indicating a full charge. The current draw indeed drops to zero and stays there, so once that green light comes on it is running off the battery - this explains the "my battery drops to 80% when I unplug the charger" phenomenon.
-d
So far I cannot get the EVO to draw more than 480mA. I've cross-connected the USB Data+ & Data- signals at the power supply end as this is what the OEM charger wall wart does (I 'beeped' those signals out in the charger and they are indeed connected together). Also, the OEM charger does not apply any measurable voltage bias on those two data signals (which is how Apple chargers work). I'm using the OEM USB cable to connect to the phone.
Finally I set up the OEM charger so that I could measure what the charger draws from the wall socket - 51mA (AC) at 114 VAC. That's about 5.8 watts. Sure sounds like it's drawing 1000mA! Grrr.
So I used a USB breakout adapter in-line with the OEM charger and OEM cable. Nope - 480mA. I didn't really think the OEM charger was 100% efficient. So I see no evidence that using a charger that supplies > 500mA results in quicker charging. So far, anyway. My battery level was at about 50% for these tests.
Also, there are threads discussing what the EVO does once that green light comes on indicating a full charge. The current draw indeed drops to zero and stays there, so once that green light comes on it is running off the battery - this explains the "my battery drops to 80% when I unplug the charger" phenomenon.
-d