myenergi Libbi Review: The EV Owner’s Battery, With Catches
The Libbi’s Zappi and Eddi teamwork is genuinely unmatched. But the price premium, the split warranty and the maker’s rocky finances all belong in an honest review.
The short answer
The myenergi Libbi is a modular UK-designed battery — stackable 5.12kWh modules up to ~20kWh, with a built-in 3.68kW or 5kW hybrid inverter — and for one type of household it’s close to unbeatable: if you own (or plan) a Zappi EV charger, nothing else routes your surplus solar between car, hot water and battery this seamlessly, all in one app. A Libbi 10 runs ~£5,500–£7,000 installed.
We score it 3.9/5 — very good, not the default choice. The catches: a clear per-kWh price premium over value rivals, a modest 3.68kW output on the smaller inverter, single-circuit backup only, a warranty that drops to 5 years on the inverter and controller, and a maker that posted heavy losses and cut jobs in 2024 before being recapitalised. Brilliant for Zappi households; everyone else should compare hard.
What this review covers
myenergi made its name with the Zappi — probably the UK’s best-known solar-aware EV charger — and the Eddi immersion diverter. The Libbi is the third leg of that stool: the battery that completes the “one app runs your whole home energy system” pitch. It’s a genuinely distinctive product in a market full of near-identical boxes. It’s also priced like one. Here’s the honest picture.
What the Libbi actually is
The Libbi is a modular battery-plus-inverter system. Each module stores 5.12kWh nominal (4.6kWh usable at 90% depth of discharge), and up to four stack together for around 20kWh on a single-phase home. A three-phase version scales from 10kWh to 40kWh with a 10kW inverter — one for larger homes. The stack includes myenergi’s own hybrid inverter (3.68kW or 5kW single-phase), so it handles your solar, the battery and tariff-aware grid charging in one system — the hybrid approach that’s become the 2026 default. That modularity is genuinely useful: start with 5 or 10kWh, add modules as an EV or heat pump arrives, rather than guessing your battery size for the next decade on day one.
Specs & performance
| Spec | myenergi Libbi |
|---|---|
| Module capacity | 5.12kWh nominal / 4.6kWh usable (90% DoD) |
| Max capacity | ~20kWh single-phase (4 modules) · 40kWh three-phase |
| Inverter options | 3.68kW or 5kW single-phase · 10kW three-phase |
| Cycle life | 10,000 cycles |
| Round-trip efficiency | ~94% |
| Rating / size / weight | IP65 (controller indoors) · 540×500×240mm · 58kg per module |
| Backup | Optional single-circuit “blackout backup” only |
| Warranty | 10yr battery · 5yr inverter & controller · approved installer only |
The core numbers are solid rather than spectacular. 10,000 cycles is excellent — comfortably a couple of decades of daily use — and 94% round-trip efficiency is respectable for the class. The IP65 modules can live in a garage or outside (the controller must stay indoors). The number that deserves your attention is the 3.68kW output on the entry inverter: that’s a kettle and not much else running off-battery at once. Households with heavy evening loads should spec the 5kW version — or note that a Powerwall 3 pushes 11kW.
UK prices in 2026
The Libbi is sold as an installed package through approved myenergi installers only — the 10-year battery warranty is only valid that way — so prices arrive as quotes rather than price tags. Typical 2026 figures: a Libbi 10 (two modules, ~9.2kWh usable) lands around £5,500–£7,000 installed, with extra modules roughly £2,000–£2,500 each, and 0% VAT applying until 31 March 2027. That’s squarely mid-market — cheaper than a 10kWh setup from Tesla, but noticeably more per usable kWh than value brands like Fox ESS or Sunsynk. What you’re buying for the difference is the ecosystem — so the question is whether the ecosystem is worth it to you.
The ecosystem: where the Libbi is genuinely unbeatable
One app, three devices, zero wasted sunshine
This is the Libbi’s whole argument, and it’s a good one. Pair it with a Zappi EV charger and an Eddi diverter and the myenergi app becomes air-traffic control for your surplus solar: you set the priority order — car, battery, hot water — and the system routes every spare watt accordingly, switching in real time as the sun and your usage change. No other mainstream UK battery coordinates an EV charger and an immersion diverter natively like this. For an EV household already invested in myenergi kit, choosing a different battery means giving that up — which is exactly why Zappi owners are the Libbi’s core market, and why for them it’s arguably the best battery on sale.
The app itself is polished: import, export, battery state and every device in one view, with tariff-aware charging that fills the battery on cheap overnight rates ready for the morning. If you’re the sort of household that will actually use the priority controls — sunny Saturday, car needs charging, tank’s cold — the Libbi turns a juggling act into a settings screen.
The catches — read before you buy
The warranty split. The battery modules get 10 years, but the inverter and controller — the electronics working hardest — are typically covered for just 5. An out-of-warranty hybrid inverter failure in year seven is a £1,000+ bill. Factor it into the value maths, and note the warranty only stands if an approved myenergi installer fitted the system.
Backup is one circuit, not your house. The optional “blackout backup” keeps a single dedicated circuit alive in a power cut — fridge, router, a few lights. There’s no whole-home gateway option as with a Powerwall 3 or GivEnergy’s All-in-One. If outage resilience matters to you, spec that circuit on day one and set expectations accordingly.
The company behind the warranty. We flag this on every brand we review, fairly: myenergi hit turbulence, posting a £24.5m pre-tax loss for the year to May 2024 as revenue fell from £67.5m to £55.6m, with over 100 redundancies and a co-founder stepping back. The counterweight is real: it raised £28.6m of fresh investment from Energy Impact Partners, holds HSBC backing, remains active at Companies House with a board including former Tesco chief Sir Terry Leahy — this is a recapitalised company trading through a hard patch, not a GivEnergy-style administration. But as we always say: a warranty is only as good as the company behind it, and the Libbi asks for a decade of trust. Worth knowing; not, on current evidence, a reason to walk away.
The premium. Per usable kWh, value rivals undercut the Libbi meaningfully. If you don’t own a Zappi and never will, you’re paying for an ecosystem you won’t use — and a Pylontech, Fox or Sunsynk system does the plain storage job for less.
Libbi vs Powerwall 3 — and the UK rivals
| myenergi Libbi 10 | Tesla Powerwall 3 | |
|---|---|---|
| Installed price | ~£5,500–£7,000 | ~£7,400–£10,500 |
| Usable capacity | ~9.2kWh (expandable to ~18.4) | 13.5kWh |
| Output | 3.68–5kW | 11kW |
| Backup | Single circuit (optional) | Whole home, built in |
| Expandable | Yes — modular 5kWh steps | Add whole units only |
| EV/diverter integration | Native (Zappi + Eddi) | None native |
The honest read: on pure battery performance per pound, the Powerwall 3 wins — more capacity, triple the output, real whole-home backup. On flexibility and ecosystem, the Libbi wins — modular growth and the Zappi/Eddi teamwork Tesla simply doesn’t offer. Against the UK field, GivEnergy undercuts it but carries its administration caveat; Fox ESS and Sunsynk beat it on value; none of them match the app. If you’re retrofitting a battery to existing solar rather than buying the full hybrid system, read our AC vs DC coupling guide first — it changes which products make your shortlist.
Our score: 3.9 / 5
myenergi Libbi — brilliant for Zappi homes, a premium for everyone else
The bottom line: If a Zappi charges your car, the Libbi is probably your battery — the one-app control of car, hot water and storage is unmatched, and the modular design grows with you. Everyone else is paying a premium for an ecosystem they won’t use, with a 5-year inverter warranty, single-circuit backup and a recently-recapitalised maker in the mix. Very good — for the right home.
Get my free quotes →myenergi Libbi: pros & cons
✓ Pros
- Unmatched Zappi + Eddi integration in one app
- Modular — grow from 5kWh to ~20kWh (40kWh 3-phase)
- Excellent 10,000-cycle chemistry
- Hybrid inverter included; tariff-aware charging
- UK company, UK design & support
- 0% VAT until 31 March 2027
✗ Cons
- Per-kWh premium over Fox ESS / Sunsynk
- 3.68kW entry inverter is limiting
- Backup is a single circuit — no whole-home option
- Inverter & controller warranty only 5 years
- Approved-installer-only purchase & warranty
- Maker posted heavy 2024 losses (since recapitalised)
Frequently asked questions
What is the myenergi Libbi and how does it work?
A modular UK battery system: 5.12kWh modules (4.6kWh usable) stacking to ~20kWh single-phase or 40kWh three-phase, with myenergi’s own hybrid inverter (3.68/5/10kW). It stores surplus solar, charges on cheap overnight rates, and — its party trick — coordinates with the Zappi charger and Eddi diverter in one app so you choose whether spare solar goes to car, battery or hot water.
How much does a Libbi cost in the UK?
A Libbi 10 (~9.2kWh usable) typically runs £5,500–£7,000 installed in 2026, with extra modules ~£2,000–£2,500 and 0% VAT until 31 March 2027. It’s sold only through approved myenergi installers — the warranty depends on it — and sits at a per-kWh premium over value brands like Fox ESS.
Is the Libbi any good?
We score it 3.9/5. For Zappi-owning EV households it’s arguably the best battery available — the ecosystem is unmatched. It loses marks on price, the entry inverter’s 3.68kW output, single-circuit backup, the 5-year inverter/controller warranty, and the maker’s recent (since-resolved-by-investment) financial turbulence.
Libbi vs Tesla Powerwall 3 — which is better?
Powerwall 3 wins on raw performance: 13.5kWh, 11kW output, whole-home backup, ~£7,400–£10,500. The Libbi wins on modular flexibility and native Zappi/Eddi integration at a lower entry price. Zappi households: Libbi first. Pure performance-per-pound buyers: Powerwall or cheaper UK rivals.
What warranty does the Libbi have?
10 years on the battery modules, but typically only 5 years on the inverter and controller — and it’s valid only when bought and fitted via an approved myenergi installer. myenergi itself was recapitalised after 2024 losses; trading and backed, but as with every brand: a warranty is only as good as the company behind it.
Does the Libbi work in a power cut?
Only partially: an optional “blackout backup” output keeps one dedicated circuit live (fridge, router, lights). There’s no whole-home gateway. Without the backup circuit specified at install, the system shuts down in a cut like any grid-tied battery — see our backup guide for the three levels of protection.
The verdict
The Libbi is that rare thing in the battery market: a product with a genuine, defensible USP. The Zappi + Eddi + Libbi trio, run from one app with your priorities set once, is the slickest home-energy ecosystem in the UK — and for the growing number of Zappi-owning EV households, that makes the Libbi the natural, probably correct, choice despite the premium.
For everyone else, honesty demands the comparison: you can buy more storage, more output and longer electronics cover for less from the value brands, or more raw capability from a Powerwall 3. Add the 5-year inverter warranty, single-circuit backup and myenergi’s recently patched-up finances (a recapitalised UK company trading through a hard patch — noted fairly, not fatally), and the Libbi lands as a very good specialist rather than an all-rounder: 3.9/5. The right way to decide is to see it quoted against the alternatives for your actual home, usage and tariff — a couple of free, no-obligation quotes from MCS-certified installers will show you quickly whether the ecosystem is worth the premium for you.
Important
Going Solar UK is an introduction service, not an installer or financial adviser. This review reflects publicly available information and typical UK pricing as of August 2026; prices, specifications, warranties and company circumstances change, so always confirm current details with an approved installer before purchase. Scores are our honest editorial opinion, not a guarantee of performance. Savings depend on your usage, tariff and system design.
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