A solar battery is one that receives its energy from the sun or from some other light source through the use of photovoltaics. In most cases, a solar-powered battery is implanted in an electronic device and not capable of being removed. A solar powered battery is usually capable of fully charging after just an hour or two of exposure to sunlight.
The surest evidence of a solar battery is an array of solar cells, usually in a line or perhaps in a block, somewhere on the device. These cells collect the light and cause electrons in semiconductors to begin to move along that semiconductor and to metal contacts. Once at these metal contacts, the energy generated can then be stored in a solar cell, or it may be put to direct use.
If that energy is stored, the solar powered battery will discharge it at the appropriate time. For example, that time may be when it is turned on by a person, or it may come on automatically, as with some lighting applications. The power is then drawn from the solar battery much like it would be any other battery.
The types of solar batteries most often used are lead acid and nickel cadmium. The lead acid batteries are cheaper, but come with a number of restrictions, such as not being able to be fully discharged. Nickel cadmium batteries do not have these restrictions, but are generally more expensive. In the long run, given the durability of the battery, this may be the most economical option. Most products with a solar powered battery will make use of nickel cadmium.
While much talk has been made about the potential of solar energy as an alternative energy source, there are some drawbacks to solar power. Currently, the technology is mainly used only for smaller electronic applications. While it may be possible to build a solar power system that will take care of home energy needs, the solar powered batteries needed would be immense. There are systems available, but they are prohibitively expensive for most people.
Despite these limitations, the solar powered battery still has numerous practical uses. It can be used for lighting, as previously mentioned. In this case, it saves the landscaper from having to run wires to lights, which can be a significant hassle. Plus, the energy gained is free. Other applications include calculators and keyring displays. However, those wishing to use this technology with a calculator should make sure it has a solar battery. Many calculators simply convert light to electrical energy for immediate use but have no ability to store that energy.