Home battery backup without solar: what works

How a battery works without panels

A home battery doesn’t care where its electricity comes from. Without solar, it charges from the grid, usually when power is cheapest, and holds that charge until you need it. In a power cut, it disconnects your home from the grid and runs your backed-up circuits exactly as it would with solar.

The one thing it can’t do without panels is recharge during a long outage. Once it’s empty, you wait for the grid to come back. That makes sizing more important: the battery has to cover the whole outage you’re planning for, on its own.

Most installed batteries can be fitted without solar, though some products are designed mainly for solar homes. When you ask for quotes, say up front that you don’t have panels.

Three reasons to buy one

Backup. The simplest case. The battery sits charged and takes over in an outage. Here, a battery competes with a generator or a portable power station, and its advantages are silence, instant switchover and no fuel.

Time-of-use savings. If your electricity price changes through the day, the battery can charge when power is cheap (overnight, typically) and run your home when it’s expensive. This is called arbitrage, and it’s the main way a battery without solar saves money.

Utility programs. Some utilities pay battery owners to send stored power to the grid during demand peaks. New England’s ConnectedSolutions program, for example, pays per kilowatt delivered during summer peak events. Not every program accepts batteries without solar, so check the rules.

On a flat-rate tariff with no program available, a grid-charged battery is only a backup. It won’t save money, and the roughly 10% of energy lost charging and discharging adds slightly to your bill.

The maths of time-of-use savings

The daily saving is roughly:

energy you shift × (peak price − off-peak price ÷ 0.9)

The 0.9 accounts for round-trip losses: you buy about 10% more than you get back.

UK example. Say you shift 4.5 kWh a day from a 28p peak rate to an 8p off-peak rate with a 5 kWh battery. You buy 5 kWh at 8p (40p) and avoid 4.5 kWh at 28p (£1.26), so you save about 86p a day, or around £310 a year if you do it every day. The government’s median installed price for batteries under 6 kWh was £1,300 per kWh in 2025/26, which puts a 5 kWh battery at about £6,500 and the payback at around 20 years. Some suppliers sell 5 kWh battery-only systems from about £4,000, which brings it nearer 13 years.

US example. Say a 13.5 kWh battery shifts 12 kWh a day on a plan with a 20-cent gap between peak and off-peak. That’s roughly $2 a day after losses, or about $750 a year if you use it daily. Against EnergySage’s typical installed price of about $13,500 for a Powerwall 3, that’s nearly 20 years, before any state incentive or utility payment.

These are illustrations with round numbers. Your own tariff, how much you can actually shift, and any program payments decide the real figure. The point they make is consistent, though: arbitrage alone rarely pays for a battery quickly. It works best stacked with backup value you care about and any payments your utility offers.

Incentives in 2026

US: the federal 30% tax credit for home batteries ended with the One Big Beautiful Bill Act and doesn’t apply to batteries placed in service in 2026. Some states and utilities still offer rebates or performance payments for storage, including for batteries without solar in some programs. The DSIRE database lists what’s available by state.

UK: installed batteries are zero-rated for VAT until 31 March 2027, and that includes batteries fitted on their own, without solar.

The cheaper alternative

If backup is the main goal and your outages are usually measured in hours, a portable power station does much of the job for a fraction of the cost. A 1 kWh unit costs roughly $500 to $800 in the US and runs a fridge for most of a day. Larger expandable models, from about 4 kWh, can be connected to home circuits through a transfer switch fitted by an electrician.

They won’t save you money day to day, but they also don’t need a permit, an installer or a decision about solar. Our EcoFlow vs Jackery comparison covers two of the most popular ranges.

When a battery without solar makes sense

• You have a time-of-use tariff with a big gap between peak and off-peak prices.
• Your utility runs a battery program that accepts systems without solar.
• Outages are frequent or long enough that silent, instant backup is worth paying for.
• You expect to add solar later and want the battery in place first.

If none of these apply, start with a portable power station, and revisit the idea if your tariff changes or you add panels. For the full cost picture, see what solar battery storage really costs.