I'm stepping up to the Thunderbolt from the Droid, and I notice the tip from my Droid's charging cord fits the Thunderbolt perfectly - so is it safe to use my Droid's cord and wall adapter to charge the Thunderbolt? Also, I found that my iPod car charger (the cigarette lighter adapter itself) worked perfectly to charge my Droid; should that hold true for the Thunderbolt?
I'm guessing that whatever mechanism actually steps down the current is in the phone itself, not in the adapters . . .
This is a variable situation. I own the Droid and TB myself. The Droid charger outputs 850mA vs the TB 1A, not too much of a diffence there. The only thing you will notice is that it take a little bit longer to charge the TB with the Droid charger. Take computer usb ports for instance I'm sure you can all vouch that it takes forever to charge your phones when connected to a usb port on a computer. Let me put it like this the amp output on the computer is so low that it couldn't turn my completely drained Droid on when I connected it to the usb port on the computer to charge it. I had to connect it to the wall charger to get the phone to come on and that's because the usb ports output 500mA vs the 850mA from the Droid charger or 1A from the TB charger. Some phones will tell you when you plug a charger in that is rated higher on amps then the charger that came with the phone that the charger isn't the right one for that phone, as what happend with my enV touch being connected to the Droid charger.
As for car chargers I own a motorola one and it's rated to output 500mA-950mA, it just depends on the demand from the device that is charging. Most of your univeral chargers will be rated to output 500mA just like the usb ports on computers.
Up until last night I haven't ever had a issue charging my Droid using my TB charger. What I noticed was that I would turn the Droid screen off while it was connected to the TB charger and it would turn itself back on as if the phone was completely shutdown and then plugged up to charge. My phone is set to NOT stay awake when charging, so that wasn't the issue. So I turned it off again and it came back on and I did it again and it came back on. At this point I'm thinking the only thing that makes the screen come on besides alarms from applications is the phone initially be connected to a charger or some sort and I viewed the side of my phone to verify that the white charging status light was staying lit and it wasn't. The phone was connecting and then disconnecting continously from the charger. So I plugged it into the original charger and the symptoms disappeared.
With regards to the output voltage, I'm reading that +-10% or the stock charger's output voltage should be fine. So 5.0V versus 5.1V isn't going to cause and issues.
So after the long winded story I'm concluding that it's ok to take a phone that demands more amps like the TB and use a lower amp output charger, just look at the fact that all smartphones nowadays can be charged via the usb port on the computer. I'm not too sure anymore about taking a device that demands lower amps and connected to a charger that can puts out more amps. In theory it shouldn't be a problem though because the charger should only output the amount of amps demanded by the phone, which has been fine me up until last night.
I'm going to play with my Droid and TB charger a little more to see if it was just coincidental and will post a update.
