Will Archai work with my inverter? Where we stand with Solis and Fox ESS

"Will it work with my inverter?" is the first question most installers ask us, and rightly so. An optimiser that doesn't play nicely with the inverter is worse than no optimiser at all. So here's a plain account of where we stand.

Solis: certified

We hold an official compatibility certificate with Solis, issued in September 2025. Solis is one of the most widely installed inverter brands in the UK, and our certification covers current Solis inverters.

As part of that process we also completed a residential install in Stockport with Archai optimisers on partly shaded strings. Post-installation testing showed a consistent 10–15% uplift on the shaded strings compared with the baseline, and the system passed all its commissioning checks. You can read the full case study.

Fox ESS: certified for single-phase

We're also certified with Fox ESS for their single-phase inverters. The models we've confirmed directly are the H1-6.0-E-G2 and the KH8, and more Fox ESS models are in testing now.

Three-phase Fox ESS inverters aren't covered yet. Testing is ongoing, and we'd rather say that plainly than round it up. If you have a three-phase Fox ESS job coming up, ask us and we'll tell you exactly where it stands.

Everything else

If your inverter isn't Solis or Fox ESS single-phase, please don't assume either way. Send us the make and model before you quote and we'll tell you honestly whether we've tested it, whether it's in our testing queue, or whether we'd advise against it for now.

Why certification matters

An optimiser changes how a string behaves electrically. The inverter still has to track its MPPT correctly, start up cleanly in the morning, ride through shading events and shut down safely. Certification means the inverter manufacturer has tested that combination and is satisfied it works. It protects the installer and the customer.

How to check a job

• Confirm the inverter is Solis, or Fox ESS single-phase.
• Check every panel against the optimiser limits: 800 W, 70 V Voc, 23 A Isc.
• One GT gateway per string, up to 30 optimisers.
• Anything unusual? Send us the design first.

Ask us where your inverter stands: get in touch or email hello@archaipower.com.