Tag Archives: Batteries


Do I need ‘batteries’ with my ‘Solar System’?

Print pagePDF pageEmail page

Solar and Batteries

When some people think about solar, they might think that they will become free from “The Man,” because a battery will allow them to store any excess power they generate, thus taking them off the grid. While this is possible with solar, it doesn’t make much financial sense for most people. Allow us to explain:

  • Grid Tie Solar

    Most solar systems are “grid tied” these days. That means when the system is generating power during the day, any excess power it makes is fed back into the grid through something called “net metering.” Your meter spins backwards and the utility credits you for that power. At night or on overcast days, you’ll use grid power instead of solar, but your utility doesn’t charge you until you’ve used up all the credit you generated through your panels. More on grid tie solar.

  • It Means You Probably Don’t Need Batteries

    You don’t need batteries for your solar system if you’re already connected to the grid. It’s an option, but not one that most people use these days because the batteries are still very big and bulky. They’re also expensive and need to be replaced every five to ten years, depending on the type and how well you take care of them. Battery technology is evolving and solar batteries may become a more viable option someday, but for most people right now, it’s more practical to simply tap the grid in off hours.

  • Net metering – The Virtual Battery

    Net metering is like a virtual battery. The utility keeps track of any extra power your solar panels produce, which spins your electric meter backwards. Then at night, you simply use grid power on the credit you earned while supplying the utility company with power during the day. Net metering is maintenance-free and typically costs around $5 per month in administrative fees.

  • What about ”?

    It’s true, our name has “off the grid” in it. It’s just a metaphor. We want to take at least one block’s worth of grid energy usage out of every city per campaign, but the bottom line is that we’re here to help you buy solar panels for your home.

Solar Battery Back-up Systems

We understand that some people are interested in solar batteries in the interest of disaster preparedness, and because this is America, you’re free to spend your hard earned money any way you want. Here are a few things to consider in your decision though:

  • Battery back-up systems are reliable for those “what-if situations.”
  • However, those “what-if” situations are fairly rare. The American electric grid is over 99% reliable, and using a battery would mean you’ed be spending an extra $5,000 to $10,000 every 10 years for the 1% chance that you will need battery back up.
  • Also, disasters that upset the grid are typically repaired within days. There are, of course, exceptions like Hurricane Katrina…..but:
  • It would most likely be more cost effective to spend money on flashlights, candles, matches, batteries, extra blankets, and dry good food, water, radio, etc, and be without the modern conveniences for a few days than it would be to purchase an expensive battery. Even in Hurricane Katrina’s case, your entire roof could have been blown away and/or your battery system under water and ruined. Same for an earthquake. Having a battery back up system may not be so important if the rest of your house is unlivable.
  • Bottom line: Battery back-up systems do work, but they’re expensive for the few times they’re needed. It’s more cost effective to prepare to live for a few days without electricity until power is restored.