Solar Powered Landscape Lighting
Solar powered landscape lighting may provide some or even all of the answer to your landscape lighting needs. As solar cells continue to improve, it becomes more and more possible to get the kind of illumination and longevity you need. Even areas that are constantly overcast are candidates for solar lighting these days. The newer cells work without direct sunlight, building up a full charge even on cloudy days.
Still, clouds aren't the only things that can block out the sun. You need to consider where you might wish to place your landscape lighting. It won't be much use if the solar cell is under a tree or bush or on a side of your house that stands in shadow for much of the day. Even bird droppings can provide interference and become a consideration.
One way around this problem is to get a solar cell that isn't attached directly to the light it powers. You position the cell where it's likely to get a good amount of sun. Then you run the weatherproof cabling to wherever you'd like the light to shine at night. In many cases, this is more fuss than you need to go through. Many solar landscaping needs can be addressed with an all-in-one unit. Just drive the stake into the ground and aim the lamp in the direction you want the light to shine.
If you find a good, open space to install the light (or the cell that powers it), you can expect 8, 10, even 12 hours of lighting per night, based on the amount of sunlight received during the day. Unfortunately, in winter time, when nights are longest, the days are correspondingly short. That means your solar lights will charge the least at times when the periods of darkness are at their peak.
Earlier versions of solar landscape lights offered much poorer light and much shorter run times. The incandescent bulbs were simply too power hungry to be very effective with the electricity that solar could provide. To compensate, the bulbs were kept at low wattage. Even then, they ran down quickly. With incandescents, solar lighting was more of an evening affair than something that took you far into the night.
That meant that landscape lighting, with its relatively large illumination needs, was often not something that could be done with solar cells. Now, many solar landscape lights use LED bulbs. These LEDs produce brighter light with less electricity than their incandescent cousins. They last longer as well. Newer nickel-cadmium and nicel-metal-hydride batteries (of the sort used in cell phones) also contribute to the efficiency of the system. They take and retain a charge much better than their lead-acid predecessors.
Nevertheless, you still shouldn't expect solar landscape lighting to be quite as bright as what you can get from a typical low voltage system.
As a last word of caution, when you buy solar landscape lights, make sure that replacement parts are available as well. The solar cells themselves practically never need to be replaced. (And if they do, it's often cheaper just to buy a new lamp.) But the bulbs and batteries should be readily available and easy to switch out.