Why is my panel kWp bigger than my inverter kW?
Short answer
Many designs deliberately fit more panel power (DC) than inverter power (AC). Panels rarely reach full rated output in the UK, and east-west arrays peak at different times, so a smaller inverter catches most energy, with some midday clipping. The limit is the inverter's maximum DC input and MPPT currents, not a fixed ratio.
Last checked 24 September 2026 · 1 source
In more detail
- No UK standard mandates a DC:AC ratio; secondary UK guides cite 1.1-1.3 typical, higher for east-west.
- DNO limits (G98/G99) apply to AC registered capacity.
- Powerwall 3 AC output configurable 3.68-11.04 kW with up to 20 kW STC PV input.
The facts, dated
- 01Powerwall 3 nominal AC output settings range — 3.68-11.04 kW
manufacturer · UK · checked 24 September 2026 · energylibrary.tesla.com
What we saw in the field
[QA review 2026-09-24] C2-2 AGREES (ratio ~1.23). C2-3 CONTRADICTS as AC (see note). | Earlier notes: Agrees: customer 2 fitted 13.5 kWp on ~11 kW (ratio ~1.23) and saw peaks ~12 kW in late June. Note: the ~12 kW peak exceeds the 11.04 kW single-phase AC rating in the datasheet - may include battery discharge or be a DC/app reading; treat as unverified.
Sources
- energylibrary.tesla.com — energylibrary.tesla.com/docs/Public/EnergyStorage/Powerwall/3/Datasheet/en-uk/Po…
Last checked: 24 September 2026