Option A
Solar panels only
A standard solar PV system exports unused daytime generation and uses grid power when solar output is low.
Solar panels vs solar battery: which is better value?
Updated June 2026 9 min read
Quick verdict
A battery can greatly increase self-consumption and annual savings, but it adds several thousand pounds upfront and may lengthen payback. Panels only are simpler and cheaper; panels plus battery suit homes that use most electricity in the evening or want backup options.
Option B
Solar + battery
Solar panels plus a battery store spare generation for later use, increasing self-consumption and reducing evening grid imports.
Side-by-side comparison
Solar panels only usually have the lower upfront cost and faster simple payback. Solar plus battery can save more each year by storing daytime generation for evening use.
Upfront cost
Solar panels only
£5,500 to £7,500Better
Solar + battery
£9,500 to £13,000
Annual saving
Solar panels only
£400 to £700
Solar + battery
£800 to £1,500Better
Self-consumption
Solar panels only
40% to 60%
Solar + battery
70% to 90%Better
Export income
Solar panels only
Higher because more is exportedBetter
Solar + battery
Lower because more is self-used
Backup power
Solar panels only
No
Solar + battery
Possible with the right inverterBetter
Best for
Solar panels only
Daytime users and lower budget
Solar + battery
Evening users and energy independence
| Compare | Solar panels only | Solar + battery |
|---|---|---|
| Upfront cost | £5,500 to £7,500Better | £9,500 to £13,000 |
| Annual saving | £400 to £700 | £800 to £1,500Better |
| Self-consumption | 40% to 60% | 70% to 90%Better |
| Export income | Higher because more is exportedBetter | Lower because more is self-used |
| Backup power | No | Possible with the right inverterBetter |
| Best for | Daytime users and lower budget | Evening users and energy independence |
Pros and cons
Solar panels only pros and cons
Pros
- ✓Lower upfront cost
- ✓Simpler installation
- ✓No battery replacement cost
- ✓Faster simple payback
- ✓Export income through SEG
Cons
- -Lower self-consumption
- -Less evening solar use
- -No backup power
- -Still buy grid electricity at night
Solar + battery pros and cons
Pros
- ✓Much higher self-consumption
- ✓Greater annual savings
- ✓Can provide backup power if specified
- ✓Can pair with cheap overnight tariffs
- ✓More energy independence
Cons
- -Higher upfront cost
- -Battery replacement after 10 to 15 years
- -Longer payback in some homes
- -Needs space and extra equipment
Cost examples
Home worker
If you already use solar during the day, adding a battery may only add modest savings.
- Battery case
- Weaker
Out during day
A battery can store daytime solar for evening use, making the upgrade more attractive.
- Battery case
- Stronger
EV or smart tariff
Battery storage can work well with cheap overnight tariffs, depending on controls and tariff rules.
- Best fit
- Smart tariff
When to choose Solar panels only
- ›You want the lowest upfront cost
- ›You are home during the day
- ›You want a simpler system
- ›You prefer faster simple payback
- ›You do not need backup power
When to choose Solar + battery
- ›You use most electricity in the evening
- ›You want higher self-consumption
- ›You want backup capability
- ›You can afford the extra cost
- ›You use smart or off-peak tariffs
Calculator
Calculate your own figures
Use the calculator below for a personal estimate, or open the full tool for the complete calculator page.
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FAQs
Is it worth adding a battery to existing solar panels?
It can be if you export a lot during the day and buy electricity in the evening. It is less compelling if you already use most solar generation as it is produced.
How long do solar batteries last?
Many lithium batteries last around 10 to 15 years, with warranties often based on cycles or retained capacity.
Can a solar battery power my home in a blackout?
Only if the system is designed with backup or islanding capability. Standard grid-tied systems usually shut down during outages.
What size battery do I need?
It depends on evening use, solar generation and tariff. Many typical homes consider around 5 to 10 kWh.
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