Can You Make Money With Battery Storage?

When we first started fitting these setups just 18 months ago, barely anyone knew they existed.

Fast-forward to 2025, and we’re now installing them in homes across the UK for people who simply want cheaper, smarter energy - no solar required.

But the big question remains: can you really make money with just a battery?

Let’s dig into the numbers, explore how the tech works, and see how savvy homeowners are turning their batteries into mini money-making machines.

PS We offer MCS-certified battery installation nationwide. Simply answer these questions, get your fixed price, and arrange your free design.

What Does “Battery-Only” Actually Mean?

Most people still picture home batteries sitting neatly beside a set of solar panels - store the sunshine, use it later, job done.

But battery-only systems flip that idea on its head. Instead of relying on solar, they draw power directly from the National Grid, charging up when electricity is cheapest and discharging when it’s most expensive.

Think of it as buying energy at wholesale prices and using it at retail value.

During off-peak hours (typically midnight to 5 a.m.), electricity prices can drop as low as 7 p/kWh.

Charge your battery then, and you’ve effectively secured cheap power to use throughout the day - when rates hover closer to 28 p/kWh.

And here’s the clever bit: you don’t just save - you can earn.

Thanks to the Smart Export Guarantee (SEG), you can sell surplus energy back to the grid, with some 2025 tariffs paying up to 22 p/kWh during evening peaks.

🎥 Prefer video? Check out our YouTube video explaining the financial rewards of adopting battery storage:

How the Setup Works

A battery-only system looks almost identical to a solar-plus-battery setup - just without the panels on the roof.

You’ll typically have:

• A lithium-ion battery (e.g. Alpha Smile G3) - wall-mounted indoors or outdoors.

• An inverter - converts DC battery power into the AC electricity your home uses.

• A smart meter and companion app - tracks energy usage, battery charge, and off-peak tariff windows in real time.

Here’s what happens behind the scenes:

During the night:

→ The battery charges from the grid at the low off-peak rate.

During the day:

→ It discharges to power your home when electricity prices rise.

At night again:

→ It automatically recharges, repeating the cycle 24/7.

Case Study #1: Inside a Heatable Customer’s Battery

To move beyond theory, we pulled data from an Alpha Smile G3 system recently installed for one of our customers.

Here are their specs:

On a typical 24-hour cycle, this customer’s energy graph shows:

• Midnight – 4 a.m.: battery charges from 0 → 100 %

• Daytime: battery gradually discharges, powering the home

• 11 p.m.: battery reaches ~20 % and cheap period begins again

By timing appliance use overnight and letting the battery handle the day, they reduced grid consumption at peak rates almost entirely.

Energy Breakdown:

Without a battery:

• 21.29 kWh × £0.28 = £5.96 per day

• With battery + off-peak tariff:

• 20.6 kWh × £0.07 = £1.44 per day

👉 Daily saving: £4.52

👉 Annual saving: ~£1,642

And remember: this customer has no solar panels whatsoever.

That’s purely from time-shifting electricity use.

Case Study #2 - Turning Storage Into Income

Our second customer used the same Alpha inverter (3.68 kW) but a larger 16.1 kWh pack (15.3 kWh usable).

Their approach was different: export energy back to the grid at peak times for profit.

Their Setup:

The Strategy

1. Charge overnight (00:00 – 05:30) when rates are low.

2. Use minimal power during the day.

3. At night, export the remaining energy back to the grid at 22 p / kWh.

The Maths

• Energy bought to fill battery: 15.29 kWh × £0.07 = £1.07

• Energy exported: 9.1 kWh × £0.22 = £2.00 earned

• Additional household saving from load-shifting ≈ £1.00

• Net daily gain: ~£3.00

Over a year, that’s £1,000+ - and again, no solar panels involved.

Why Sizing & Tariffs Matter

Getting the size of your battery - and the tariff that powers it - right is what makes or breaks your savings.

1. System Sizing

Your battery should ideally run down to around 20–25% by the end of the day.

If it regularly hits 0%, it’s too small for your home’s needs.

For most UK homes (using 8–12 kWh per day), a 10–14 kWh battery hits the sweet spot.

Bigger homes or properties running heat pumps typically benefit from 15–20 kWh+ setups.

2. Tariff Selection

A flat-rate tariff will wipe out your savings before they start.

To make a battery-only system pay off, you’ll need either:

• A dual-rate tariff (e.g. Economy 7, Octopus Go, Intelligent Octopus, or OVO Charge+) - cheap overnight, pricier daytime.

• Or an agile/dynamic tariff that adjusts prices hour-by-hour and pays you for exports.

Some agile users even enjoy negative prices, where the grid literally pays you to charge your battery during surplus wind generation.

The Tech Behind It: Alpha, Octopus & the Kraken API

Here’s where things get seriously clever…

One of Heatable’s preferred battery system - the Alpha Smile G3 - now integrates directly with Octopus Energy’s Kraken platform, the same smart system that powers their Intelligent Octopus and Agile tariffs.

In simple terms, this connection lets your battery think for itself. Using real-time pricing data, the Kraken API allows your system to:

• Buy energy when prices dip - charging up automatically during cheap overnight or negative-rate periods.

• Sell energy when prices spike - exporting back to the grid when demand (and payout rates) surge.

• Optimise in real time - using half-hourly settlement data to constantly tweak when to charge, discharge, or hold energy.

The result? A system that quietly trades energy on your behalf - buying low, selling high, and cutting your bills without you lifting a finger.

And this is just the start. As the UK shifts toward a fully flexible, decentralised grid, home batteries like the Alpha will become the backbone of energy arbitrage - ordinary homeowners helping to balance national supply and demand, while turning a tidy profit in the process.

What About Conversion Losses?

No battery is perfectly efficient - and that’s totally normal.

Each time your system charges and discharges, a small amount of energy is lost as heat. In practice, that’s around 5–10%, depending on your inverter and setup.

But the price gap between cheap off-peak rates and daytime peak prices is usually three to four times higher. So even with those minor losses, you’re still well in profit.

In short, yes - a few watts slip through the cracks, but the savings easily make up for it.

⚠️ Key Takeaways from the Data:

• You can make money with just a battery - no solar required.

• Real-world users are saving £1.5 – £2 k per year or earning up to £3/day through exports.
  
  The crucial ingredients are:
  

• A reliable, smart-enabled battery

• A dynamic or off-peak tariff

• Smart scheduling for high-draw appliances

⚠️ Avoid flat-rate tariffs - they erase all benefit.

⚠️ Don’t cheap out on hardware - batteries cycle daily for years.

Choosing the Right Battery

Heatable currently offers several tried-and-tested options:

*Fixed prices including VAT and full installation.

All are modular - you can add capacity later if your usage (or heat pump) increases.

Next Steps For Your Battery Journey:

When planning to install battery storage for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:

• What size battery do you need? 

• What is home battery storage? 

• Battery storage without solar panels 

• Pros and cons of battery storage

To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos, or read a customer case study to see how others have benefited from their battery installation. 

Get a Quote for a Battery Today

Without boasting, you should get your battery storage installed with us, here's why: 

• Thousands of Happy Customers: We boast an average score of 4.9 on Trustpilot, outperforming the market leader.

• Which? Trusted Trader: Heatable is proudly recognised as a Which? Trusted Trader.

• Tesla Certified Installer: Heatable is proudly certified and approved by Tesla to install the Powerwall.

• MCS Accredited: Our accreditation by the Microgeneration Certification Scheme (MCS) ensures high-quality standards.

• Consumer Protection: As members of the HIES consumer code, we provide 2-year deposit protection.

• Flexible Payment Options: Choose from multiple payment methods, including finance options.

• Fixed Price Guarantee: Enjoy transparency with no hidden costs.

• Save Your Quote: You can save your quote and decide later.

• Bespoke Battery Quote Tool: Find out which battery is ideal for your home, here.