spycedtx: You're not remembering enough of the basic EE ;-)
gowen: Lithium batteries can be charged with a low current, it should simply take longer. The problem could be that your USB port isn't as well regulated as it's supposed to be, i.e. the load of the 770 may result in the USB voltage dipping down and get too low. You will need to measure with a meter to figure out what happens. (Actually, sticking in that resistor will lower the current drain of the USB port and may thus help the port to keep 5V, but that doesn't help anyway because the voltage _behind_ the resistor (i.e. at the 770) will be lower).
Two ports in parallel might actually work though.