I use single cell lights with a 3 volt cut-off so I don't worry about the protected circuit. This is a good source for the Panasonic 3400's. http://www.fasttech.com/products/142...0mah-37v-18650
This would be a good charger for that battery with the 2amp charge rate. http://www.orbtronic.com/batteries-c...harging-speeds It will also charge 26650's.