Electric bills suck. So does wasting power using more light than you need to. I try to light the house by sunlight whenever possible, but when there's a mid-sized planet between the giver of free light and my windows this becomes more difficult. Since I had a few battery and some 12v lights around though I figured all I needed was a solar panel and I could harvest the power of that giant burning gravity well for my nocturnal illumination.
All five dollar words and odd perspective aside though, I've come up with a pretty straightforward solar setup for my bathroom and reading lamp. I have a small 1.5 watt solar panel up on my roof held down with 3m tape with a wire run to my room on the other side of the house held down by duct tape (renting a house makes permanent mounting unideal) Then the wire runs to the charge controller that came with the solar cell into either a 12v car jump start pack or a pack of two 7.2AH lead gel cell batteries in series with a switched car accessory adapter on it. The batteries are manually swapped every other day to keep them well charged.
Then the batteries feed lights. I have a simple 10w 12v car work light in the bathroom and a desk lamp with another 10w 12v light. They're not going to blind anyone, but for reading a book or getting a shower or going to the loo at night they're plenty bright.
Also, I needed a ladder to get up to the roof, but I didn't have one. Having already blown my (nonexistent) budget on the solar panel itself and knowing I don't really need a ladder often I set out to make one. I did have some sisal rope, nails, and some decent sized oak saplings around the house in the woods, so I made a pretty rickety but serviceable ladder from them. I'm hoping once the wood dries and shrinks some I can rebuild it and have it more sturdy than with the current green wood. I'll probably reclaim my lag bolts from my dad at some point to hold it all together as well. I'm still sure OSHA would have a fit even then though.
In the future I'd like to mount a larger 5 watt solar cell on the roof as well since they're only twice the price of a 1.5 watt cell, run the charger to both packs at once, and make the wiring and power switch for the bathroom more cleanly run. It takes 6 2/3 hours to recharge for every hour of use with my current setup. Replacing the lamps with LED lamps or adding a larger solar panel would make that better, but for my current use it's enough.