Take a look at this, I haven't bought it yet, but I think its the only way to charge the razr on the go.
https://www.verizonwireless.com/b2c...ryDetails&archetypeId=12824&accessoryId=47872
I have it and it works as expected. Since it's made by Motorola, and for Motorola products, it is your most appropriate choice, however it will only charge the phone once, and doesn't provide a 100% charge from a completely dead phone. It will charge to 100% if the phone has around 20% remaining.
The difference between this one and many of the others out there is that this one is a true "CHARGER", not just an external power source. What I mean by that is, this will unload its charge onto the phone and drain itself when you press the charge button. Other external power sources only drain as the phone uses it up, so there is always at least as much left in the external power source as there is in the phone. If the phone has for instance 900mAh still in it, and the external power source has 900mAh, the external power source will not actually charge the phone, but will allow the phone to use the power from itself as part of its own. In other words, they will both drain equally until they are both empty.
The way to tell one from the other is if the charger has a button that you actually activate the charging process from, and if the phone doesn't actually detect the charger as having been plugged in until that button has been pushed, then you know you have a "charger" and not just an external power source. This may not be 100% accurate of a way to determine one from the other, but if the external source doesn't have any buttons, you can be relatively sure it's not a "charger".
There are others out there that are true "chargers" and have a much larger battery reserve. I have seen some as large as 8000mAh, and I know there are even larger ones. The sacrifice is that with the larger ones, they are physically larger as well.
