Form SB—01 · Guide
What is a solar battery?
A solar battery, also called a home battery, stores electricity so your house can use it later. That is the whole idea. Everything below is the detail behind it: how it works, what kind to get, what it costs, and whether it earns its keep.
A home battery stores energy, either from your solar panels or from the grid when power is cheap, and releases it when you need it: during an outage, or in the evening when electricity is most expensive. In 2026 a typical installed system runs $9,000 to $17,000 for a single unit before incentives, and the 30% federal tax credit runs through 2032.
What a home battery actually does
Electricity is normally a just-in-time product. It is generated, sent down the wire, and used in the same instant. A home battery breaks that rule. It lets your house hold energy and decide when to use it.
That one change unlocks two things homeowners care about. The first is backup: when the grid goes down, a properly installed battery keeps your lights, refrigerator, internet, and chosen circuits running. The second is savings: you can store energy when it is cheap or free, such as midday solar production, and use it during the expensive evening peak instead of buying from the utility.
"Solar battery" and "home battery" mean the same thing
The terms are used interchangeably. "Solar battery" is the common search phrase because batteries became popular alongside rooftop solar. But you do not need solar panels to own a home battery. Many homeowners install a battery on its own, purely for outage backup, and charge it from the grid. Throughout this guide we use "home battery," and we mean the same thing as "solar battery."
How a home battery works
A home battery system has three parts: the battery itself, an inverter, and a controller or transfer switch. The battery stores energy as direct current. The inverter converts between that stored DC and the alternating current your house and the grid use. The controller decides, moment to moment, whether to charge the battery, discharge it, or pass power straight through.
Charging happens when energy is available and cheap: your solar panels are producing more than the house needs, or grid power is in an off-peak window. Discharging happens when energy is expensive or unavailable: the evening rate peak, or a blackout.
Grid-tied versus backup-capable
This distinction matters more than any spec sheet number. A plain grid-tied battery without backup wiring will actually shut off during an outage, for the safety of utility line workers. To keep your home running when the grid is down, the battery has to be installed with a critical-loads panel or a whole-home transfer switch, so it can safely "island" your house, disconnecting from the grid and powering your circuits on its own. If outage protection is the reason you want a battery, this is the part to get right. Any installer we match you with has done islanding-mode commissioning on the battery they recommend.
Battery chemistry: LFP, NMC, and lead-acid
Not all batteries are built from the same materials, and the chemistry shapes safety, lifespan, and cost.
LFP (lithium iron phosphate)
LFP is the modern standard for home batteries, and every model we work with uses it. It runs cooler, tolerates a wider temperature range, resists thermal runaway better than older lithium types, and lasts longer measured in charge cycles. It is slightly heavier per unit of energy, which matters very little for a battery bolted to a wall.
NMC (nickel manganese cobalt)
NMC packs more energy into less weight, which is why it is common in electric cars. In a home, where weight is not a real constraint, its lower thermal tolerance and shorter cycle life make it the weaker choice. Some older home batteries still use it.
Lead-acid
Lead-acid is the old technology, the same chemistry as a car battery. It is cheap upfront but heavy, short-lived, and requires maintenance. For a modern home battery install it is rarely the right answer.
How big a battery do you need?
Capacity is measured in kilowatt-hours (kWh). The right size depends entirely on what you want the battery to do.
For critical-loads backup, where the battery powers essentials like the refrigerator, lights, internet, and a few outlets, a single battery of roughly 10 to 15 kWh is usually enough to ride through an overnight outage and into the next day.
For whole-home backup, where the battery carries the entire house including air conditioning through a multi-day event, you generally need a stack of two or three units and a whole-home transfer switch. Air conditioning is the demanding part: a large central AC unit draws heavily, and running it on battery often requires both extra capacity and a soft-start kit on the compressor.
The right answer is rarely the biggest box. Oversizing a battery wastes money on capacity you never discharge. This is the single most useful thing a knowledgeable person can do for you, and it is what happens when you submit our form: a real person sizes the battery to your actual home and load profile.
What does a home battery cost?
In 2026, a single-unit home battery typically costs $9,000 to $17,000 installed for a 10 to 15 kWh system, before incentives. A whole-home stack of two or three units runs $20,000 to $35,000. The spread depends on the brand, your home's electrical service, and how much rewiring the install requires.
Incentives change the real number. The federal tax credit covers 30% of the system cost and runs through 2032. California's Self-Generation Incentive Program (SGIP) can take off more, with the largest rebates going to medically-vulnerable households and homes in high-fire-threat districts. Texas has no statewide battery rebate, though the federal credit still applies and a few utilities run time-limited programs.
Does a home battery pay for itself?
It depends on why you bought it. If the goal is purely financial, the payback math is real but slow, and it has improved sharply in places where the rules changed. In California, the shift to NEM 3.0 cut the credit utilities pay for exported solar by roughly 75%. A battery flips that math: instead of selling your midday solar back cheaply, you store it and use it during the expensive evening peak. For many new California solar customers, the battery is the part of the system that makes it pay back at all.
If the goal is resilience, the math is different. The value of keeping your refrigerator cold, your medical equipment running, and your home livable through a multi-day outage is not measured in cents per kWh. For a household in a region with an unreliable grid, that is the entire point, and a payback calculation misses it.
Common misconceptions
"A battery automatically keeps my house on during a blackout."
Only if it is installed with backup wiring. A grid-tied battery without a critical-loads panel or transfer switch shuts off during an outage. The installation matters as much as the battery.
"I need solar panels to get a home battery."
No. Many homeowners install a battery alone for outage backup and charge it from the grid. Solar makes a battery more valuable, but it is not a requirement.
"Bigger is always better."
Oversizing wastes money on capacity you never use. The right size is the one that matches your home and your reason for backup.
"All home batteries are basically the same."
They are not. Capacity, chemistry, inverter design, warranty length, and installer network all differ. See our battery brands page for an honest comparison.
How to choose
Start with why you want a battery: outage backup, bill savings, or both. That answer drives the size, and the size narrows the brand. From there it comes down to your home's electrical service, your existing solar if you have it, and which installers near you are certified on the right battery.
That is the work we do. When you submit our application form, a real person reviews your home, recommends a battery and a size, and introduces you to one licensed installer we trust to do the job. It costs you nothing, and you can read more about how we work and how we are paid before you decide.