a seven amp battery isn't much. i wouldn't use it maybe a couple of charges that's it. you can buy a motorcycle type battery of maybe 15 - 20 amp hr. or better yet a lawn tractor battery. they are high rated around 75 amp hr. these will last awhile in the field. put a strap, clothsline rope etc......non -conductive, from post to post for carring it. like a handle. they ain't that heavy or cumberson. they have power for charging for electrics also will supply enough amps to turn over bigger four strokes, even with a standard or h-d tower hobbies or hobby-co starter. also buy a battery maintainer for you battery. plug it in and leave it on the battery all the time. won't over charge and you will have a fully charged battery every time you go to the field................my .02...............................happy flying and charging................................RON