These INSTEN batteries for the Canon LP-E5 provide backup for my Canon XSi factory batteries, which seem to not hold a charge as long as they use to. The INSTEN batteries work equally well as the Canon factory batteries. For a while I was charging them with the Canon charger. Then a little bird told me that maybe I should purchase the associated INSTEN battey charger. Some Canon cameras/chargers are real finicky about using generic batteries. Now that I have the INSTEN battey charger, I feel I have sufficient battery power for those long photo days off-site.