Solar systems with batteries have skyrocketed in popularity in recent years, primarily because the cost of batteries has dropped, and their capabilities have increased. Solar plus storage offers greater resiliency and energy independence, especially in areas prone to natural disasters or with an unstable electric grid.

Although lithium-ion storage batteries were prohibitively expensive in many markets, this trend is changing. The Tesla Powerwall has gained considerable media attention, even though various manufacturers make quality residential and small commercial battery systems.

Blackouts and Solar Power

Unfortunately, solar panels need battery storage to operate during a power outage. If the solar system doesn’t have batteries, it will automatically shut down during an outage to protect utility workers. Battery backup is needed to provide power to homes and businesses during a blackout.

A critical load panel determines which appliances and electronics will get power from the batteries. This involves prioritizing loads until the utility power is restored. Batteries have a limited capacity. It is often not recommended to power certain circuits that use a lot of power because they will exhaust the batteries, especially at night or in cloudy weather. For example, it might be more urgent to keep the refrigerator on to prevent food from spoiling than to power an electric water heater or air conditioner.

The Benefit of Solar Batteries

Some utility companies charge more for power at certain times of the day. Solar systems with batteries can save money on utility bills by consuming the batteries’ power when rates are highest.

Having backup power may be critical for some homes and much less essential for others. For example, sump pumps can help prevent basements from flooding during storm events, an issue that is irrelevant in some regions. Likewise, medical or communication equipment might also be critical for some homes and businesses.

Solar Battery Options

There are several battery options to choose from, including deep-cycle lead-acid, lithium-ion, and saltwater batteries. Essential aspects of battery storage are the battery’s capacity, power ratings, warranty, and depth of discharge.

The capacity indicates how much energy the battery can hold, and is measured in kilowatt-hours. The power rating indicates the amount of power the battery can provide at a given time. The depth of discharge relates to how much of the battery’s capacity can be consumed relative to the total capacity. To protect battery life, don’t exceed the depth of discharge of a given battery, as indicated by the manufacturer.

Batteries or No Batteries?

Ultimately, the decision on whether to get solar batteries depends on many factors. Before making a decision, consider if:

  • It is crucial to have backup power during outages.
  • The power rates vary significantly by the time of day, resulting in cost savings from batteries.
  • The power grid is unstable in the given area and is more prone to extended outages.
  • A backup generator is an attractive option, despite disadvantages including noise, space, servicing, and fossil fuel use.

The cost of lithium-ion batteries has fallen considerably in recent years, and technology has improved. This trend is likely to continue, so many people interested in batteries are holding off for the moment.