I have a solar panel rated for 3v 150mA which gives out around 3.3v 90mA normally and I'm planning to charge 2x1.2v 1100 mAH NiMH batteries in series during daytime and run 2x 0.5W white leds at night for 3-4 hrs. I realize the batteries wont fully charge and so even 3 hrs is an over estimated value, but I dont know how to run 4v white leds on 2.4v. I have seen circuits for 1.5v, but here I have 2.4v. Any idea what to do?