Most solar powered lights stay on for 8 to 10 hours if the solar panel has had a full day's sunlight to charge the battery. If you're looking to install solar lights in a part of your shade garden, for example, they'll need some exposure to direct sunlight to stay lit. Fortunately, solar lights are easy to move around because there are no cords or wires to deal with. You can easily place the shade area lamps in the sun all day, and they will work well that evening.
Over the years, the batteries and bulbs in solar garden lights have improved. Solar lighting used to appear dim, and the batteries wore out quickly. Now LED lights are used more often, and the batteries themselves have become not only more efficient but also less expensive.
This old real estate saying, "Location, location, location," applies equally to solar lighting for landscapes. An important part determining location is considering what task the lighting will accomplish. Accent lights, pathway lights and task lights all have a specific purpose and use.
Accent lights are true to their name. These are the lanterns you see hanging from trees or globes, marking a place in the landscape, and aren't meant to guide you through a dark garden. The best accent light uses a multi-crystalline solar cell that can charge even during a cloudy day. Because this type of light is meant solely to accent, a dimmer light is fine. You don't need a bright white LED bulb for this purpose.
Pathway lights should guide your guests through the landscape and are a bright white LED bulb. For instance, you may want to illuminate a pathway from the front garden to your door. These lights are focused downward so no one trips or falls. An on/off switch to save battery life is a smart feature on solar path lights.
Task lighting is necessary when you want to light up a particular spot like up-lighting for a tree in your yard. Task lights are the real workhorses in the solar light arena and also carry the heftiest price tag. A huge advantage to this kind of lighting is that often you can separate the solar cell from the light itself so the cell can charge independently, which works especially well if the item you're lighting is a large tree and the light wouldn't normally get a lot of sunlight.
If you're using just accent lights and long for atmosphere and romance, a few lights scattered here and there are fine. If you're lighting a pathway, the general rule is to place a solar light every two feet on either side of the path for the best illumination. For task lighting, only one or two lights are needed. A task light of high quality puts out the equivalent of light from a 40-watt incandescent bulb, so you may want to use two of them should you have a feature that needs more light.
Another consideration for solar lighting is the number of LED bulbs a fixture requires. The brighter the light, the more LEDs you'll need. Take a look at the lights before purchasing to see how many LED bulbs are needed.