I have these batteries in addition to the Varta-fast charger (15min Ultrafast) bought which mitlieferte 4x 2500 battery from the same manufacturer. The 2500 is working properly, are charged in 15 minutes and keep in a digital camera for 250 pictures by. The 2700, however, were absolutely disappointing. Within three days, they lost their charge, were therefore useless. Grade with a branded product, I expect quite something more, besides, I do not understand how such a defect can slip through the quality assurance - especially since it is not an isolated phenomenon, as suggested by other reviews.