Solar Batteries – the Path to Energy Independence and Power When You Need It

Solar batteries offer a way to get even more value out of your solar panels. Whether you have already installed a solar array or are planning to do so soon, solar batteries can be added onto your system to increase your energy independence and energy security by giving you up to 24 hours of solar power every day.

As we like to say, solar batteries allow you to ‘own your power’ even more than you already can with solar panels.

On this page you’ll find answers for all the basic questions about solar batteries. This is a central resource for anyone wanting all the information they can get about solar batteries in one place.

We’ll discuss the benefits and risks of solar batteries, solar battery prices, solar battery brands, batteries and power outages, what to look for when shopping for solar batteries, and much more.

Bookmark this page and use it as a starting point for finding out what you need to know about solar batteries.

And if you have further questions and want to talk to a solar battery specialist, you can get a solar quote from a solar consultant or contact us here.

What are the main benefits of solar batteries?

Are solar batteries worth it?

Let’s start off by looking at the main benefits and then some of the downsides of solar batteries. Some of these apply to everyone, while others apply more to homeowners or more to businesses and farms.

An enphase battery system neatly installed on a wall of a comfortable, modern house in warm sunshine.

Save more money

However much energy your solar panels are able to produce, your solar batteries will increase your efficient use of it. By storing any excess power and then using it later, you’ll avoid any losses that may occur when transferring the excess to the grid. And you’ll maximize your financial return on investment by avoiding cut rate net metering that doesn’t fully reimburse you for the power you produced.

You’ll also save money if your utility charges higher rates at certain peak usage times of day, because your solar batteries will ensure that most of your energy needs beyond what your panels can produce will be supplied by the battery, and not the utility.

Possible 100% power offset

With enough solar panels and sufficient solar battery storage, you have the potential to pay nothing for power, month after month. Your panels produce during the day, and your batteries use the stored excess solar energy to power your home at night.

Backup power source

Most solar battery brands allow you to continue powering your home even in a power outage. You’ll never need to worry about all your frozen foods thawing out or the milk rotting in the fridge.

You can be the only house on the block with air conditioning after a hurricane. You can be the only hotel still operating, the only restaurant still serving cooked food, etc.

Be mindful that installing a solar battery doesn’t mean instant backup power by default. You’ll need the right setup and the proper equipment. So talk to a solar consultant about your exact situation.

Protects you from rising energy costs

Solar panels save you money, but those savings increase over time because the power companies will keep increasing their rates. However, because you are producing your own power, you don’t have to pay those higher rates until your energy usage exceeds what your panels can produce.

With solar batteries, you can store your excess and use even less of the utility’s power. And that means you’ll pay even less of ever-increasing energy prices.

Positions you as eco friendly – customers love it

For businesses in particular, going solar can make your company a bigger draw because there are certain customers who will go out of their way to support businesses that prioritize care for the environment. Use it in your marketing. And if you have solar batteries, you can amplify this even more.

Protects you from cybersecurity threats

Like it or not, we live in a world where just about anyone can be a target of cyberterrorists — including power companies. If your power company became a victim of ransomware or some other cyber threat, this could affect your ability to receive power from the utility. With solar batteries, you won’t have to worry about that threat.

A close-up shot of a macbook keyboard and screen in a dark room with computer code on the screen.

Here are more reasons why solar batteries would make a great addition to your solar panel system.

What are the downsides and risks of solar batteries?

It’s not all rosy. Like anything else, there are pros and cons to solar batteries. Here are a few of the downsides of using batteries:

They’re an extra investment

Costs vary quite a bit by brand and type, but solar batteries aren’t free. Though you’ll earn a higher return on investment each day by using more of your solar power, you will also have spent quite a bit more to earn that privilege.

So, your break even point, when your solar system has saved you more money than you spent on it, will likely be farther out than if you just bought panels. Again — this is not true in every case, and the details matter, but for most people, batteries do push your break even point back a few years.

That’s why many who buy solar batteries do so for reasons beyond the financial savings. You’re also getting them for the convenience during a power outage, the energy independence, and the security, as mentioned in the list of benefits you just read.

Power outages are a bit more complicated

When the power goes out and you have solar batteries, it might not be quite as simple as just cruising ahead like nothing has happened, especially if the power goes out at night. If you try to continue powering all your home systems — including heat, AC, water heater, and any other big energy guzzlers — your batteries may run out of stored energy sooner than you’d like.

Depending on how much battery storage you have and other factors, you may have to ration your power usage during an outage to ensure that your most critical systems like freezers and fridges keep functioning.

How do solar batteries save money?

Monetary savings from solar batteries come from a few different places. Some of them depend on how your utility company handles solar and net metering. Let’s start there.

Net metering losses

If you live in a place with a utility that provides fully compensated net metering, then solar batteries would not save you money on this particular point — but they still would on the others.

However, if your utility doesn’t fully reimburse you for the excess solar energy you send to the grid, that means you’re losing money on your excess power. By storing that power in your batteries, you will regain the full value.

For example — suppose you pay 15 cents per kWh, but your utility only pays 10 cents per kWh for excess solar power you send to the grid. That means you’re losing up to 33% of the financial benefit your solar panels are making possible. Some utilities pay even less than that. Some offer no metering at all.

The worse your net metering policy, the more money you will save with solar batteries because you won’t have to send hardly any energy to the grid, since you’ll be using it yourself instead.

Peak shaving

What is peak shaving? It means you’re using one of three possible approaches to reduce your costs during the times of day when your energy usage is highest.

For many businesses, peak usage happens during the day. Your solar panels will produce the most energy during the day too, and that will greatly reduce your daily energy costs, even without batteries.

For homeowners and certain businesses, they tend to use the most energy in the evenings, when solar isn’t producing as much. For them, solar batteries offer a way to escape dependence on the utility during times of peak usage. That’s a major cost savings — especially if you have an unfavorable net metering policy.

A sleek, silver Enphase solar and storage system installed in a nice home garage

Peak power rates

Related to peak shaving, some utilities charge extra high fees during times of day with the most usage. If you are caught in the crosshairs of that type of utility, then the savings you’ll earn from solar batteries during peak usage times will be even higher.

You’ll save money in two ways: First, because you’ll be supplying free solar energy from your batteries during the times of day when you use the most energy — peak shaving. And second, you’ll be saving on the extra high rates charged by the power company during those times.

Using solar energy at night

Even if you have a favorable net metering policy and don’t suffer from extra high peak power rates, solar batteries will still save you money because they enable you to use your stored solar energy at night. This avoids needing to rely on the utility or pay their rates during those hours.

And, some power gets lost in the transition from your panels out to the grid. So what you’re earning from net metering isn’t quite as much as if you stored it all and just used it yourself.

Bottom line — the worse your deal with the power company, the more you will save with solar batteries. But even with favorable power company terms, you still save money.

How long do solar batteries last?

The best solar batteries come with at least a 10-year warranty, which means you can expect them to last considerably longer than that.

However, any rechargeable battery loses some of its ability to recharge over time. This is known as ‘depth of discharge.’ It may start off with a 90% depth of discharge. But a typical solar battery warranty will say something like this: “After ten years, your battery will have at least a 70% depth of discharge.”

So, it still ‘works’ after ten years, but it is not working as efficiently. And the longer you keep using it, the less efficient it becomes. This is true of all solar batteries. But some retain higher depth of discharge for longer. This is one reason behind what you’ll discover to be sizable price differences between brands.

Another way to measure how long solar batteries last is through cycles.

The Tesla Powerwall, for example, is warrantied for 3200 cycles. Assuming it cycles once per day, which you would expect, that’s 8.7 years. Eguana, a brand we offer, warranties 6000 cycles, almost twice as long.

And remember, solar battery companies don’t want to have to pay anything from warranties. So you can be pretty confident that your battery will outlast the warranty.

Ten years is a solid minimum expectation. Fifteen years is reasonable too for most brands. For high end brands like sonnen, you can expect twenty.

Do solar batteries work in a power outage?

Surprisingly, it depends on the brand and the technology.

Any off-grid solar battery obviously works in a power outage, because you’re already off the grid, so you’re essentially always having a power outage.

For the rest of us, you’ld need a hybrid solar battery — one that can function whether the grid is on or off.

In that case, if the power goes out, your solar battery can continue to charge with solar energy during the day and supply power to your home up to a certain limit determined by the type of battery.

If having solar battery backup power is an important reason why you’re considering solar batteries, make sure you get a brand that will continue to operate during an outage.

And even in that case, you have to be sure your battery is properly configured with the power systems in your home or business. For instance, you may not want your batteries to power everything, as that runs the risk of draining the battery overnight before it can recharge. This risk is amplified if you end up with a cloudy, snowy, or rainy day during the outage.

When your batteries get installed, you can set it up so that you can control which systems in your home or business the battery is powering. This is essentially a new electrical subpanel, with its own set of breakers. Find out more about keeping power on during a blackout or a hurricane.

Your solar consultant can provide more details when you request a free solar power quote.

What about gas generators?

Historically, gas generators have been more commonly used as a means of backup power. But as you are well aware, they come with a number of annoyances – such as the need to refuel them, potential for breakdown, and more.

Gas generators are also potentially more expensive over the long term than solar batteries when considering them as a means of backup power.

What makes a solar battery good?

As you’ll quickly find out when you start looking, there are a surprisingly large number of solar battery brands. How do you narrow it down and make a smart choice?

A solar battery consultant can speed up the process, but even on your own, you can make quite a bit of headway if you know a few basic facts.

First, let’s define “good.”

In our estimation, a good solar battery does three things:

  1. It lasts longer
  2. It’s more efficient
  3. It’s safer — for you and for the environment

What to look for when shopping for solar batteries

Which approach is best for you might depend on a number of factors, such as price per battery, how much physical space you have wherever you plan to put the batteries and recommendations from experts.

Battery power – how much power your battery can supply to your house

A low power rating means your battery can only power a certain number of systems in your home at one time. As an analogy, imagine a hose connecting your battery to your home’s power outlets and systems, and the power flows through this hose. A narrower hose would mean less power can flow at one time, and a wider hose would mean more power can flow.

The power rating, in effect, tells you how wide the ‘hose’ is. A higher power rating means your solar batteries can sustain more systems in your home or business.

This circles back to the question of power outages. If you expect your solar battery to power a larger percentage of your systems in an outage, then you will need a battery with a higher power rating.

two computers side by side on a table with papers scattered about. A solar consultant is advising a potential client.


A good warranty is worth paying extra for if it means your battery will last longer and be more efficient. Look for years of the warranty, how much depth of discharge is warrantied within that time frame, and how many cycles are warrantied.

Compatibility with your situation

Most importantly of all, the solar batteries you purchase must fit your current situation. This applies to your reasons for wanting batteries, as already mentioned. But it also refers to the status of your current solar panels, if any.

Not all solar batteries are compatible with all panels. Sometimes it depends on the size of the array. Sometimes it depends on the brand.

If you want batteries because you can save money and negate the high cost of your power bills during peak usage times, this might not matter to you. But if you want batteries to provide backup power during an outage, then this very much matters to you.

So when shopping for solar batteries, know what you’re looking for. Here’s more about what to look for when buying solar batteries.

What about Tesla’s Powerwall solar batteries?

In terms of efficiency, longevity, and safety – the three primary measures of a ‘good’ solar battery – sonnen and Eguana beat Tesla. Tesla’s battery is good, but here’s a more detailed comparison between Tesla and these other two solar power battery brands.

Solar battery prices — what does it cost?

You will be spending several thousand dollars on solar batteries, regardless of the path you choose. For many systems, it will end up being over $10,000 once you include installation. For the high end brands, expect it to be more.

Talk to a solar consultant and ask them to create a few scenarios for your specific home or business.


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