NiMH 1.2V 1/3 AA 280 mAh is it possible the claim made for size and capacity?
2200mAh AA (14500) NiMH cells are available commonly, so 280mAh for a 1/3AA actually sounds a little low. I would expect 600mAh from that size instead.

Rather than putting multiple 1/V150Hs in series you might be better with one or more 4/V150Hs or 5/V150Hs on the same page. Putting them in parallel will let you easily hit your 2h life.