i have used barnacle also, and charging with the laptop is almost useless. but an idea is to actually go and turn the phone upside down, and take off the battery cover and let it sit that way. that will keep the heat from going directly into your phone. another alternative is to slide open your phone and turn off the screen (having the screen on while this wastes the battery even more)
but something that ive found whenever im using a heavy data connection like with barnacle is that if you are plugged into the computer, have a data connection to your computer (wireless or cable) and have your screen on, it will show that the battery is still decreasing even though you are plugged in.
FIX= just turn off your phone screen and this will slowly charge your phone backup. but you are still better using the wall outlet for charging while doing this.