Bought one of these after having success with the transmitter pack. It works equally as well. Same size as a regular pack, many times more powerful. I now carry two to the field (One in the plane and one spare) and can fly all weekend long and then some and never have to worry about low battery voltage. Since they don't seem to discharge like Nicads when sitting, I can even get in a few flights during the week if the opportunity arises. I use the standard wall charger and let it charge for 2-3 days (They don't get hot at all). Have not tried fast charging yet. (Posted on 9/28/12)