This charger works just great. i tried 1, 2 and the 3 battery options. The charge time was the same if 1 battery, 2 batteries or three are pluged in. I give 2 thumbs up to the FNDN Folks.
While the USB charger which came with my base layer is useful for on the go, the normal plug charger is great and I can top up all three batteries for the base layer at once. Seeing as I'm packing in moving now at the end of November, it's made working outside moving boxes and stuff much more pleasant.