how do solar battery backups work?
dennis asked:
how do one separate the backup from the main supply
This entry was posted
on Monday, August 31st, 2009 at 12:00 am and is filed under Engineering.
You can follow any responses to this entry through the RSS 2.0 feed.
You can leave a response, or trackback from your own site.
how do one separate the backup from the main supply
August 31st, 2009 at 10:12 pm
Depending on what exactly your setup is, it may be as simple as a diode to prevent the battery from discharging through the solar panel.
But there is a slightly more complicated circuit/device that is also sold at RV places where you have two sets of batteries a main and an auxilary, like the car battery for the main and inside lighting for aux. It has three sets of terminals - charging source, main and aux and prevents back flow and cross flow but charges both batteries.
September 1st, 2009 at 7:38 pm
Solar panels charge the battery bank through a solar charge controller which keeps the batteries from over charging. A grid-tied battery backup inverter is used to convert the DC electricity from the batteries to AC, which is used by your household appliances. The inverter is also connected to the electric grid through your house breaker box. Any extra power generated by the panels once the batteries are full will be sent to the main power panel and used by the household. If you generate more than you use, it can be sold back to the electric company.
Generally for a battery backup system, a separate breaker box is set up for your “critical loads”, things you have to have running in the event of a power failure. When the inverter senses the grid has gone down during a power outage, it will feed the critical loads panel from the battery bank. Everything that is connected to your regular breaker box will go out, only those designated for backup will stay on. If it happens during a sunny day, the solar panes will continue to charge the batteries as they are being used. Once power is restored to the grid, and the batteries are fully recharged, everything goes back to normal.
You can checkout a small grid-tied battery backup package at