Tesla Powerwall 3 vs myenergi libbi
Tesla Powerwall 3 stores 13.5 kWh per unit, expanding to 94.5 kWh. myenergi libbi stores 4.6 kWh per unit, expanding to 18.4 kWh. Across the setups we list, continuous power is 11.04 kW for the Powerwall 3 and 3.68–5 kW for the libbi. Warranty: 10 years vs 10 years. Intelligent Octopus Flux: Powerwall 3 is “On Octopus's integration list”; libbi is “Not on Octopus's list”.
Figures from manufacturer documents, last checked 26 Sept 2026. We don't rank products or take payment for results.
How they're built
Tesla Powerwall 3
All-in-one: battery with built-in hybrid solar inverter (solar connects on the DC side).
Backup: Backup Gateway 2 (required for backup installs).
myenergi libbi
Hybrid inverter plus separate battery modules; works with new DC solar or alongside existing solar (AC coupled).
Backup: Optional: backup to a dedicated socket or lighting circuit (extra installation).
Side by side
| Specification | Tesla Powerwall 3 | myenergi libbi |
|---|---|---|
| Usable capacity (per unit) | 13.5 kWhAC, minimum at beginning of life, 25°CTesla datasheet, p.2 & p.4 | 4.6 kWhPer 5 kWh modulemyenergi datasheet, p.3 |
| Battery chemistry | Not documented | LFP (LiFePO₄)myenergi datasheet, p.3 |
| Maximum usable storage (expanded) | 94.5 kWhMultiple Powerwall 3 units and/or ExpansionsTesla datasheet, p.1 | 18.4 kWhcalculatedmyenergi datasheet |
| How it expands | Up to 4 Powerwall 3 units and up to 3 Expansion units (max 7 units)Tesla datasheet, p.2 | 1–4 battery modules in parallelmyenergi datasheet, p.3, BMS: Modules connection |
| Continuous power (per unit) | 11.04 kWInstaller-configurable: 3.68, 5, 6, 7, 8, 9, 10 or 11.04 kWTesla datasheet, p.2, Nominal AC Output Power at 230 V | 3.68–5 kW3.68 kW or 5 kW invertermyenergi datasheet, p.4, Nominal AC output power |
| Peak power | Not documented | 6.9 kW6.9 kVA for 10 seconds, backup outputmyenergi datasheet, p.4, AC output (backup) |
| Round-trip efficiency | 89%Solar → battery → home/grid, typical use caseTesla datasheet, p.2, footnotes 1 & 3 | Not documented |
| Architecture | All-in-one: battery with built-in hybrid solar inverter (solar connects on the DC side)Tesla datasheet, p.1 & p.3 solar specifications | Hybrid inverter plus separate battery modules; works with new DC solar or alongside existing solar (AC coupled)myenergi datasheet, p.1–2 |
| Max solar input | 20 kWMaximum solar STC inputTesla datasheet, p.3 | 4.8–7.5 kWcalculatedmyenergi datasheet, p.4 |
| Backup needs | Backup Gateway 2 (required for backup installs)Tesla datasheet, p.2 & p.5 | Optional: backup to a dedicated socket or lighting circuit (extra installation)myenergi datasheet, p.1 |
| Indoor / outdoor | Indoor and outdoor ratedTesla datasheet, p.3 | Not documented |
| Dimensions | 1105 × 609 × 193H × W × D as listedTesla datasheet, p.3 | 540 × 490 × 240 per module; inverter 540 × 590 × 240W × H × Dmyenergi datasheet, p.3–4 |
| Weight | 130 kgTesla datasheet, p.3 | 54 kgPer battery module; inverter 32 kgmyenergi datasheet, p.3 |
| Warranty (UK) | 10 yearsMust be reliably connected to the internet for the full 10 yearsTesla datasheet, p.2, footnote 6 | 10 yearsBattery pack; 5 years for inverter and controllermyenergi warranty, p.1 |
| Capacity guaranteed at end of warranty | 80%80% of 13.5 kWh at 10 yearsTesla warranty, p.1, retention table for Austria, Belgium, France, Germany, Ireland, Luxembourg, Netherlands, Switzerland or the UK | Not documented |
| Warranty conditions | Unlimited cycles for solar self-consumption, time-based control and backup; 37.8 MWh throughput limit for other uses. Minimum 4-year cover if not kept online.Tesla warranty, p.1 & p.3 | Unlimited cycles when managed by the myenergi controller; otherwise ends at 3 MWh per kWh of usable capacity. Must be fitted by a certified libbi installer.myenergi warranty, p.1 |
How long each runs your home in a power cut
Every setup we list for both, from a full battery with no solar. Appliance figures are typical estimates; use the calculator below with your own.
| Setup | Usable | Continuous | Essentials (fridge-freezer, lights, Wi-Fi, TV, charging) | Essentials + air-source heat pump (winter) |
|---|---|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | 11.04 kW | 3 days 10 hours | 7.7 hours |
| Tesla Powerwall 3 + 1 Expansion | 27 kWh | 11.04 kW | 6 days 20 hours | 15.5 hours |
| Tesla Powerwall 3 + 2 Expansions | 40.5 kWh | 11.04 kW | 10 days 7 hours | 23.2 hours |
| Tesla Powerwall 3 + 3 Expansions | 54 kWh | 11.04 kW | 13 days 17 hours | 31 hours |
| myenergi libbi 3.68 kW + 1 module (5 kWh) | 4.6 kWh | 3.68 kW | 28 hours | 2.6 hours |
| myenergi libbi 5 kW + 2 modules (10 kWh) | 9.2 kWh | 5 kW | 2 days 8 hours | 5.3 hours |
| myenergi libbi 5 kW + 4 modules (20 kWh) | 18.4 kWh | 5 kW | 4 days 16 hours | 10.6 hours |
Try your own appliances
Average draw 156 W from 12.83 kWh available.
Everything on at once: 415 W — within the 11.04 kW limit
- Starts from a full battery with 0% held back as reserve.
- 5% extra allowed for wiring and standby losses on top of the manufacturer's usable figure.
- Appliance figures are typical averages; your own may differ. Enter your own wattage for the most accurate result.
- Assumes no solar recharging during the outage.
- Powerwall 3: Battery chemistry is not stated in the UK datasheet.
- Powerwall 3: A peak power figure in kW is not stated in the UK datasheet; it lists motor-start capability of 185 A (locked rotor amps).
- Powerwall 3: Continuous output is set by the installer (3.68–11.04 kW). Ask what yours will be set to.
- libbi: The warranty does not state a capacity retention percentage.
- libbi: Round-trip efficiency is not stated in the datasheet.
- libbi: The newest datasheet we found is from October 2023; check with your installer for any later changes.
Questions people ask
Which stores more, Tesla Powerwall 3 or myenergi libbi?
Tesla Powerwall 3 has the higher stated maximum. Tesla Powerwall 3: up to 94.5 kWh (multiple Powerwall 3 units and/or Expansions). myenergi libbi: up to 18.4 kWh. Per unit, Tesla Powerwall 3 stores 13.5 kWh and myenergi libbi stores 4.6 kWh.
Which can run more appliances at once?
Across the setups we list, Tesla Powerwall 3 delivers 11.04 kW continuously and myenergi libbi delivers 3.68–5 kW. These are the maximums for each setup; installers can set some systems lower. Continuous power limits how many appliances can run at the same time; capacity decides how long they run.
Which has the better warranty?
Tesla Powerwall 3: 10 years, 80% capacity guaranteed at the end. myenergi libbi: 10 years, no capacity figure stated. Conditions differ, so check the warranty rows in the table above.
Do Tesla Powerwall 3 and myenergi libbi work with Intelligent Octopus Flux?
Tesla Powerwall 3: On Octopus's integration list. myenergi libbi: Not on Octopus's list. Octopus lists the battery brands it can control in its Intelligent Flux FAQ; see our Intelligent Octopus Flux page for details.
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Sources
- Powerwall 3 Datasheet (UK) — Tesla, 2026. Retrieved 26 Sept 2026.
- Powerwall Limited Warranty (Europe incl. UK) — Tesla, Rev. 1.16, effective 3 Dec 2025. Retrieved 26 Sept 2026.
- libbi Home Battery datasheet (DS-00001) — myenergi, Revision A, October 2023. Retrieved 26 Sept 2026.
- myenergi libbi-system Warranty — myenergi. Retrieved 26 Sept 2026.
- Intelligent Octopus Flux: Frequently Asked Questions — Octopus Energy. Retrieved 26 Sept 2026.
Spotted an error? See how we check data. Always confirm your final design with an MCS-certified installer.