If you already have solar, you know that when the grid goes down, your home goes dark, too. That’s because utility grid-connected systems must be isolated for the safety of the utility workers. This month is the anniversary of the famous “October Snowstorm” when power was out for more than a week. And since then we’ve had plenty of ice storms, hurricanes, falling trees, and traffic accidents that knock out the power. If you have a battery back-up system, when you lose utility power you will be instantly switched over to power from your battery, while still being isolated from the grid. This means that your solar system can start recharging the battery and powering your house. So, you’ll be covered if the power is out for a few hours or even for a few weeks. Unlike a standby generator, a battery back-up is instant, silent, and non-polluting. Plus, it isn’t dependent on expensive fuel deliveries which may be hard to get if the power outage is widespread. The batteries can be sized to supply your critical electrical needs and will begin recharging as soon as the sun shines again. New, friendly, battery technology.

Big batteries used to be smelly, not very powerful, and needed constant maintenance. Lithium-ion ones (used in cell phones, laptop computers, electrical toys and some back-up products) were a step forward, but came with other problems of safety and usable life. Now the Lithium-IRON ones (as in this Lotus SimpliPhi unit shown here) are clean, powerful and maintenance free. They have three times the energy of older designs and twice the life of current other brands.