Solar: Off Grid
Mar 5th, 2008 by solarbill
Solar: Off Grid (or Battery Backup)
Off grid systems use the solar panels to charge batteries. The power is then taken from the batteries. Some appliances can use the DC power from the batteries directly. Other appliances use power that is converted by the inverter to AC. These systems are sized so that they can do 100% of the usage. They can also be tied to a generator so that in the event there is not enough electricity from the sun the generator will kick in.
A battery back up system is a combination of the two. It is a system with batteries that is also tied to the grid. It has the advantage of supplying power to a few circuits when the utility power goes out.
The disadvantages to a battery back up system are that it costs more and needs more maintenance. It is also less efficient compared to a grid tie system, it takes more panels to produce same amount of useable power.
