Marstek
Marstek Venus E
4.0 5.12kWh
A plug-in balcony battery with a built-in 800W microinverter. AC-coupled — it charges from cheap off-peak electricity rather than panels, then powers your home at peak times.
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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 |
Our verdict
Different from the rest: the Venus E has no solar input — it's a plug-in battery for off-peak tariff arbitrage. On a tariff like Octopus Agile it can pay back through cheap-rate charging even without panels.
Pros
- Large 5.12kWh capacity
- Great for off-peak arbitrage
- No installer needed
Cons
- No solar input
- Only worth it on a time-of-use tariff