Batteries for Home and Grid

By George Harvey, staff

Currently, most people storing electricity for household use, whether grid-tied or off-grid, use lead-acid batteries. These have the same technology Grandpa used in the first car he got that had an electric starter. The lead-acid battery has advantages of a simple design and relatively low cost. Batteries for use in the home and grid go through daily charge and discharge cycles, which are of concern for their longevity. There are ways of extending battery life, however.

Battery Bank Installation. It is recommended that battery
banks be enclosed in a sealed box with venting to the outside.
Photo(s) courtesy Surrette Battery Company, Ltd

Many solar installers suggest planning on replacing the battery bank after seven to ten years. The actual amount of time depends on how the batteries are used and maintained. To get the best life, a system must be properly sized, so it does not discharge too deeply, and it needs proper maintenance. Nevertheless, lead-acid batteries can actually last longer, according to Roy A. Early, Jr., who runs RAE Batteries in Berlin, Connecticut, and knows about as much about batteries as anyone around.

RAE Batteries was founded by Roy A. Early, Sr., in 1945. He had thirty-five years’ experience, first with the Willard Storage Battery Company, and the Gould-National Battery Company, where he was a plant manager. RAE built the reputation as the maker of the best batteries in New England for automobiles, trucks, and earth-moving equipment, and supplied batteries to about 70% of the trucks in the area.

Naturally, Early spent his life working with lead-acid batteries. As he took over his father’s business, he had immense help over time from other John Surrette, another battery manufacturer, whose Salem, Massachusetts plant made batteries for marine and industrial use. Among other things, Surrette helped Early get high-quality semi-automatic manufacturing equipment.

When new government regulations caused a shutdown of RAE production lines in 1985, Surrette picked up RAE’s production. David Surrette, John’s son, had moved the Surrette Battery Company to Nova Scotia in 1959. RAE is providing their customers with batteries today that are every bit as good as what they made in the Connecticut plant.

RAE Batteries now has a line of batteries built specifically for storing backup or off-grid power for homes and businesses. They are warranted for seven years and have a life expectancy of fifteen, given good maintenance. Their newest models, the S-500EX (6 volt) and S-1400EX (2 volt) are made to standards that go even beyond what has been available in the past. The plates, for example, are 0.261-inch, where ordinary battery plates are often 0.110-inch.

Life expectancy is based on good maintenance, but it can be doubled with exceptional care. Early says that in parts of the world where getting replacements can be very difficult and costly, batteries are better cared for and last longer. “Some of ours have been in use for over thirty years in places like Cuba,” he says. Now, with RAE’s newest line of Rolls Surrette batteries, the longevity has been improved.

In addition to lead-acid batteries, a wide variety of other types are becoming available for off-grid and utility-scale applications. These include everything from nickel-cadmium and lithium-ion to liquid-flow and molten salt batteries. Apart from nickel-cadmium and lithium-ion batteries, however, most of these are not being widely produced. A good deal of research is going into grid-scale power storage, and announcements are made nearly every week.

Early points out that lithium-ion batteries still represent a young technology. He says the early problems with overheating seem to have been solved, but new issues may arise, and his position is, “We don’t sell lithium-ion batteries – at least not yet.” But he says the time may come.

Elon Musk of Tesla has put batteries into the spotlight in recent months. The news reports say that Elon Musk has decided to build what he calls a “gigafactory,” a multi-billion dollar battery manufacturing plant. Using that plant’s efficiency of scale and improved technologies, he hopes to get the price of the lithium-ion batteries used in his cars down to under $200 per kWh. He will then also sell batteries for household and grid-energy storage.

That figure might be perplexing for some people, because electricity is about 15¢ per kWh in Vermont, and lower in many other states. Remember, however, we should not be comparing the price of batteries with the value of the electricity they can store in a single charge cycle.

Market analysts say that at $200 per kWh, Tesla’s batteries are nearing a tipping point where the cost of solar or wind power, plus the cost of the batteries to store the electricity they produce, are competitive with grid electricity. This means that solar-plus-storage or wind-plus-storage can replace coal, nuclear, and even natural gas. Musk wants to accomplish his part of this in the next few years.

Musk’s solution looks like it will be coming to fruition in the near future. This means that at some point, house owners, businesses, and even communities will be able to maintain their own grid storage using lithium-ion batteries, or other types, as they develop.

Also, batteries in vehicles need to be replaced when they have only used about a quarter to a third of the service life they would achieve in a grid storage situation. This means that after electric vehicles’ batteries are replaced, the retired EV batteries can be reused for grid-scale or home storage.

The effect of this is that many analysts are predicting that not just households, but entire neighborhoods and communities, will go off-grid in the near future, generating power with solar and wind, and relying on storage for slow production times. Some expect this will happen by 2020.