Marstek Venus E
A plug-in balcony battery with a built-in 800W microinverter. AC-coupled, so it charges from cheap off-peak electricity rather than panels, then powers your home at peak times.
Not legal to self-install as plug-in solar
This system stores energy, which the UK plug-in solar rules (SI 2026/848) exclude. It can't be used under the plug-in route, so in Great Britain it needs a hardwired installation by a qualified electrician.
Checked against the ENA Type Test Register on 28 September 2026. The rules, explained
PowerGuide is reader-supported. We may earn a commission from links on this page. It never affects our rankings or what we recommend. Learn more
Our verdict
Different from the rest: the Venus E has no solar input; it's a plug-in battery for off-peak tariff arbitrage, popular in Germany. In Great Britain plug-in batteries can't be self-installed under the current rules, so it would need a hardwired installation by an electrician.
Good
- Large 5.12kWh capacity
- Designed for off-peak arbitrage
Watch out
- Not legal to self-install in GB
- No solar input
- Only worth it on a time-of-use tariff
Specifications
| Usable capacity | 5.12 kWh |
|---|---|
| Max expandable | 5.12 kWh |
| Max AC output | 800 W |
| Max PV input | 0 W |
| Cycle life | 6000 |
| Weatherproofing | IP65 |
| App control | Yes |
| AC-coupled (works without panels) | Yes |