Skip navigation to main content
University of Maryland 2005 Solar Decatholon
Solar Panel


BatteriesWhen our home is not using all of the solar electricity it is producing, say on a sunny day, batteries store the energy for future use. They are very similar in composition to ordinary car batteries, but their electrical capacities are much higher. A typical car battery is rated for 12 volts, and usually holds 40 amp-hours of electricity. Maryland's home features 32 East Penn Deka 8L16 batteries, each rated to hold 370 amp-hours at 6 volts. The total capacity of the battery system is 71 kilowatthours.

An "amp-hour" is a unit used to describe how much electricty is held in a battery. One amp-hour means that one ampere of current can be drawn for one hour before the battery is dead. This is approximately the amount of electricity that a 120 watt lightbulb would draw in one hour in a typical home, from a standard 120 volt electrical outlet. To put this in perspective, one of the batteries in the 2005 Maryland home could power 370 light bulbs for one hour, or one light bulb for 370 hours. This is in the ideal case, however, discharging a battery to zero capacity can damage the battery, so it is never done.

All of this battery capacity is necessary because every 2005 Solar Decathlon home is self-sufficient, and does not receive any grid electricity. Therefore, each home must have an electrical storage mechanism capable of powering the home for several days with very little sunlight.

East Penn Deka LogoFor more information is available on East Penn Deka's battery products at their website.

Email Webmaster     
Department of Energy Solar Decathlon Website