Adding a battery to an Enphase solar system
If you have Enphase IQ7 or IQ8 microinverters, the Enphase IQ Battery 5P is documented as compatible. For backup you also need an IQ System Controller 3 INT. Older M Series systems need an extra gateway, and the older Enphase AC Battery can't be combined with it.
Compatibility by existing system
| Your existing system | Enphase IQ Battery 5P | myenergi libbi |
|---|---|---|
| Enphase IQ7 Series microinverters | CompatibleBackup: Needs an IQ System Controller 3 INT. On a retrofit the installer removes the existing IQ Gateway, IQ Relay and CTs, because the controller includes them. In backup, solar size is limited to 150% of battery power.Source: Enphase manual, Table 1; section 6.2; sizing guideline 4 | Works via AC couplinggeneral statementmyenergi says libbi can be added to any existing solar system. This is a general statement, not specific to Enphase.Source: myenergi datasheet, p.1–2, Flexible install; use-case table |
| Enphase IQ8 Series microinverters | CompatibleBackup: Needs an IQ System Controller 3 INT. On a retrofit the installer removes the existing IQ Gateway, IQ Relay and CTs, because the controller includes them. In backup, solar size is limited to 200% of battery power.Source: Enphase manual, Table 1; section 6.2; sizing guideline 4 | Works via AC couplinggeneral statementmyenergi says libbi can be added to any existing solar system. This is a general statement, not specific to Enphase.Source: myenergi datasheet, p.1–2, Flexible install; use-case table |
| Mix of IQ7 and IQ8 microinverters | CompatibleEnphase listed this mix as available from Q4 2025.Backup: Needs an IQ System Controller 3 INT. On a retrofit the installer removes the existing IQ Gateway, IQ Relay and CTs, because the controller includes them.Source: Enphase manual, Table 1 | Works via AC couplinggeneral statementmyenergi says libbi can be added to any existing solar system. This is a general statement, not specific to Enphase.Source: myenergi datasheet, p.1–2, Flexible install; use-case table |
| Enphase M Series microinverters (older) | Needs extra hardwareNeeds: A separate IQ Gateway / Envoy-R for the M Series microinvertersBackup: In backup, solar size is limited to 100% of battery power.Source: Enphase manual, Table 1; sizing guideline 4 | Works via AC couplinggeneral statementmyenergi says libbi can be added to any existing solar system. This is a general statement, not specific to Enphase.Source: myenergi datasheet, p.1–2, Flexible install; use-case table |
| Existing Enphase AC Battery (older) | Not supportedEnphase lists the older AC Battery as not compatible with IQ Battery 5P.Source: Enphase manual, Table 1 | Not documented |
Not listed: Tesla Powerwall 3, Sigenergy SigenStor, Fox ESS EVO 10. We haven't found manufacturer documentation for using these alongside existing Enphase microinverters, so we don't claim they work.
What changes on a retrofit
- For backup, the IQ System Controller 3 INT is required. It replaces your existing IQ Gateway, IQ Relay and current sensors, because it contains them.
- Up to seven IQ Battery 5P units (35 kWh usable) can connect to one controller on a UK single-phase supply.
- During a power cut, the solar that can stay on is limited relative to battery power: up to 200% with IQ8, 150% with IQ7, and 100% with M Series or string inverters.
- The system needs Wi-Fi or wired internet as its main connection.
How long would it run your home?
Try the runtime calculator or, with a heat pump, the heat pump battery calculator.
Questions people ask
Can I add a battery to my existing Enphase system?
Yes. Enphase's IQ Battery 5P works with existing IQ7 and IQ8 microinverters. Older M Series systems need a separate IQ Gateway, and the older Enphase AC Battery can't be combined with the IQ Battery 5P.
Do I need a new gateway to add an Enphase battery?
For backup, yes: the IQ System Controller 3 INT is needed, and on a retrofit it replaces the existing IQ Gateway, IQ Relay and current sensors because it contains them.
Can I use a non-Enphase battery with Enphase microinverters?
An AC-coupled battery with its own inverter can sit alongside any solar system. myenergi, for example, says libbi can be added to any existing solar. For other brands we list the combination as not documented until the manufacturer confirms it.
Sources
- Enphase Energy System planning guide — single-phase backup systems (UK) — Enphase, TEB-00305-1.0. Checked 26 Sept 2026.
- libbi Home Battery datasheet (DS-00001) — myenergi, Revision A, October 2023. Checked 26 Sept 2026.