myenergi libbi Review UK: Price, Specs & Verdict

The myenergi libbi is a modular home battery built from 5kWh lithium iron phosphate (LFP) modules, paired with a 3.68kW or 5kW hybrid inverter, that scales from 5kWh to 20kWh. It is made by myenergi in Grimsby, the same company behind the Zappi EV charger and eddi solar diverter, and its main selling point is that all three run from one app. This libbi review is built from myenergi's own datasheet and product page plus UK retailer listings, and covers the specs, UK pricing, how it works with solar, backup power, and who should look elsewhere.

myenergi libbi at a glance

• Capacity: 5kWh modules (5.12kWh nominal, 4.6kWh usable), up to four modules, so 5, 10, 15 or 20kWh.
• Inverter: single-phase hybrid, 3.68kW or 5kW, two solar string inputs.
• Chemistry: LFP, rated for 10,000 cycles at 90% depth of discharge.
• Coupling: works as both DC-coupled (solar connects straight to the libbi inverter) and AC-coupled (retrofit to existing PV).
• Backup: optional blackout supply to a dedicated socket or lighting circuit, at extra installation cost.
• Warranty: myenergi advertises 10 years on batteries and inverters; at least one UK retailer lists 5 years, so confirm in writing before you buy.

Specs: what the datasheet actually says

These figures come from myenergi's libbi datasheet (Revision 6, March 2023). It is the latest published version we could find, so check with your installer that nothing has changed on current stock.

Two things stand out. First, a single module cannot deliver the inverter's full output: with one 5kWh module the 5kW inverter is limited to roughly 4.1kW discharge, so the 5kW inverter makes most sense with two or more modules. Second, the datasheet does not publish a battery round-trip efficiency figure, so treat any number quoted by retailers as unverified until your installer shows you a source.

How libbi works with solar and your tariff

Because libbi is a hybrid system, you can wire a new solar array straight into its inverter with no separate PV inverter, or retrofit it beside an existing system. myenergi's datasheet describes four set-ups: new solar plus libbi, libbi alone on a time-of-use tariff, adding storage to existing solar, and expanding an existing array. You choose whether it charges from solar, the grid, or both, and when charging from the grid it optimises around a time-of-use or dynamic tariff. If you are weighing the tariff side, see our guide to Octopus tariffs for solar owners and why overnight charging only pays on the right tariff.

The ecosystem angle is the real differentiator. libbi is designed to work with the zappi, the eddi and the harvi wireless sensor, prioritising stored energy to power your home, an eddi or a zappi. If you already own a zappi, our comparison of diverters, batteries and EV charging explains how the three compete for the same surplus solar, which matters when you decide what your battery should do first.

Blackout backup: read the small print

libbi's backup output is optional, and myenergi's own datasheet footnotes that additional installation costs apply. It supplies a dedicated socket or lighting circuit, rated up to 4,000VA (3.68kW inverter) or 5,000VA (5kW inverter), not the whole house. If whole-home resilience is your priority, read our guide to home battery backup power before specifying it, and make sure your installer quotes the backup circuit explicitly.

libbi price in the UK

myenergi does not publish a price on its libbi product page; quotes come from approved installers. Retailer hardware listings give a guide. At the time of writing, the libbi 5kW hybrid inverter was listed at £945 ex VAT (£1,134 inc VAT), a 5kW inverter plus 10kWh battery bundle at £3,537.80 ex VAT (£4,245.36 inc VAT), and a 5kW inverter plus 20kWh bundle at £6,375.34 ex VAT (£7,650.41 inc VAT). These are hardware-only listings and exclude installation, the backup circuit and any commissioning charges. For installed pricing context, our home battery cost guide has the current ranges.

Installed batteries in Great Britain currently qualify for 0% VAT until 31 March 2027, reverting to 5% from 1 April 2027, so the timing of your order matters. Retailer listings state the warranty is only valid if an approved installer commissions the system, so do not DIY the install; our battery installation guide covers what a proper job involves.

Where libbi is strong

• One app for solar, battery, EV and hot water. If you run a zappi or eddi, this is the tidiest set-up on the UK market.
• Flexible coupling. DC-coupled for new solar, AC-coupled for retrofits, so it suits both new installs and existing arrays.
• LFP chemistry. Generally regarded as more thermally stable than NMC cells; see our LFP vs NMC explainer.
• UK-based maker. myenergi is headquartered in Stallingborough, Grimsby, so support sits with the manufacturer rather than a distant importer.

Where it falls short

• Small modules. At 5kWh a module, you need several to reach 10kWh or more, and modular pricing tends to cost more per kWh than a single large unit.
• Weight. Each module weighs 54kg, so location matters. Check the rules in our guide to where home batteries can be installed.
• Ceiling of 20kWh on single-phase. Larger homes may outgrow it. myenergi has also been reported (Solar Magazine, April 2026) to have launched a three-phase libbi scalable to 40kWh, but we could not confirm UK availability.
• Few published performance numbers. No round-trip efficiency in the datasheet, and the datasheet itself dates from 2023.

Verdict: who should buy the libbi?

Buy it if you already own, or plan to buy, a zappi and eddi and want one app and one installer-supported ecosystem. Look elsewhere if you want the lowest pounds-per-kWh or a single large cabinet; compare against the options in our best home battery storage UK roundup and check what size battery you actually need first. Whatever you choose, get at least three itemised installer quotes that state usable capacity, inverter size, backup circuit and warranty length.