Hardware · Comparison
myenergi libbi: should you install one?
Updated
libbi is myenergi's modular battery and it is designed to sit in the same family as the Zappi charger and the Eddi diverter. That is the point of it: one app logic for solar, hot water, the car and the battery.
Where this kit fits
Homes with a Zappi, or homes about to fit a Zappi, that want the battery and the car to follow the same surplus rules. It is a weak buy when households shopping purely on the lowest price per kilowatt-hour with no interest in the myenergi stack.
Households shopping purely on the lowest price per kilowatt-hour with no interest in the myenergi stack.
A September 2026 figure for myenergi libbi
Take a 10 kWh pack, cycled about 340 times, at 90% round trip. Charge at 9.0p, and value what comes back at 30.8p. Export given up is priced at 12.0p. About 971 kWh a year of the charge is treated as spare solar from 2.5 kWp that might otherwise have been exported. Delivered energy is about 2448 kWh. After charging cost and lost export, the figure saves about £503 a year. Set that against £5,630 fitted, which is a September 2026 illustration at the temporary 0% residential rate, not a quote. That is a simple payback of about 11.2 years on these assumptions. Nudge the night rate up by 4p and see if you still like it.
In most single-phase houses in Britain, 5 kW sits above the 3.68 kW G98 line, so this wants a G99 application before anyone energises it. Export can still be capped. Agree that before the inverter is ordered. The figure uses 10 kWh and 2.5 kWp, which is enough to tell two quotes apart if they assumed something else.
At a steady 600 W evening load, 10 kWh lasts about 16.7 hours. A 3 kW kettle only works if the inverter can deliver it. Capacity on the badge does not answer that.
VAT, paperwork, refusal
Where the job is a qualifying install in a home, the 0% rate runs to 31 March 2027 and is due to become 5% after that. This figure prices the work at £5,630 on that basis. It does not apply to a shop, and it does not apply to a battery you buy and fit yourself.
I would not treat backup as included on a 10 kWh quote unless the circuits are listed.
Ask the installer for the last myenergi libbi they commissioned: postcode area, inverter size, and whether G99 was required. A first-ever install of this range is a risk you can choose not to fund.
Common questions
Is the price on this page a quote?
No. £5,630 is a September 2026 illustration for a 10 kWh example at the temporary 0% residential rate. Your survey replaces it.
Will it stay on in a power cut?
Only if a gateway or essential-load board was designed and paid for. A standard grid-tied battery turns off with the grid. On this 10 kWh example the inverter is 5 kW, and backup is still a separate line.
What paperwork should I keep?
Keep the MCS certificate where the job is certified, the electrical certificate, the DNO record, the schematic, the warranty registration and a photo of the schedule. For an illustrated £5,630 job, that folder is part of what you bought.
What if the cheap rate is not 7p?
Then the figure changes. This page used 9.0p as a charge rate and 30.8p as the rate avoided. A smaller gap means a worse payback. Read the live tariff.
Sources
Want a price for your house?
The figures above are a rough guide. An installer still needs to see your fuse board, where the battery will go, and whether you want power during a blackout.