Well, say that you ride a total of an hour a day, going to work and back 30 minutes each way. With a Dinotte 200 on High steady mode, you can get by with charging every two days with AAs, four days with the 2-cell Li-ion pack, or once a week with the 4-cell pack.

http://www.dinottelighting.com/manuals/200L_INST_A.pdf

I'm thinking of upgrading to Li-ion so that I don't have to charge so often anymore.