Help articles › Batteries
Can I add more batteries or panels?
How much each of our systems can grow, and what an upgrade involves.
Often, yes. What's possible depends on your equipment, your roof and what your network operator allows.
Adding battery storage
| Your system | What can be added |
|---|---|
| Fox ESS (EP6 or EP12 batteries) | Up to four of the same battery on one inverter, up to about 46 kWh with four EP12s |
| Duracell Energy (Dura5) | More modules, in steps of about 5 kWh. Duracell recommends no more than 10 on one inverter. |
| Tesla Powerwall 3 | Up to three Expansion packs, each adding 13.5 kWh of storage (but not extra power) |
| Tesla Powerwall 2 | Can't be combined with Powerwall 3 Expansions. Ask us about the options. |
Adding panels
Possibly, but it depends on:
- how much more your inverter can take,
- the roof space you have left, and
- what your network operator approves. Bigger systems may need a G99 application before any work starts.
VAT and planning
- Solar panels and batteries, including a battery added to an existing system, currently have 0% VAT until 31 March 2027, according to HMRC.
- Panels on a house roof are usually permitted development, so they don't need planning permission. Listed buildings, some conservation areas and some other areas have extra rules. We check this as part of the design.
What happens next
Contact us with what you'd like to add. We'll check your current design and send you a quote. Please don't add equipment from anyone else to your system: it can affect your warranties.