Need help with my ECHO 1 RED STAR Covert Full Metal AEG Airsoft Rifle Blow Back on SHORTY USA?

Yes, stick type batteries fit in AKs. If it is the same voltage (which it is) then it will work with your gun. A smart charger automatically stops charging when the battery is done, so it will not over charge. Also, you don't need to get the charger if you don't want to because the gun comes with a trickle charger, but you would need to take it off exactly at 4.8 hours. Nice gun by the way. In my opinion, speed loaders do not help with high capacity magazines, since you pour the BBs in through a hatch in the top.