^^ I don't know how much voltage fluctuation you found, but I've been using the 3300 batteries with a DR-60D, an R-44, and Android phones for almost a year now and haven't had one iota of trouble with them. As Ultfris suggested, set the voltage on the battery before plugging it into the device and you should be fine. FWIW, I performed a test with the 3300 (mentioned in another thread) switching from the highest voltage (14v) to the lowest (3v) and, IIRC, it takes about 45 seconds for it to drop from the one extreme to the other.