How big a solar battery do I need to store all my home's electricity?

Re:How big a solar battery do I need to store all my home's ... by thomas8787 on Monday September 15, 2025 @03:13PM (#45253755)

The winter months and parts of the fall months are hardest due to a lack of sunshine. Without an EV, from March until late September a 5kWh battery is enough for me to keep my daily grid power consumption close to 0. A 5kWh plug-in battery now costs around 1299EUR. Pays back itself in a handful of years.

Batteries are similar to solar panels in this regard. With solar, the first couple of kilowatt-peak delivers the biggest savings. With batteries, it's the same with the first couple of kWh of storage capacity.

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Re:How big a solar battery do I need to store all my home's ... by tomekf on Monday September 15, 2025 @03:14PM (#45253783)

What battery you have in mind? Can you share name/model?

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Re:How big a solar battery do I need to store all my home's ... by thomas8787 on Monday September 15, 2025 @03:43PM (#45254071)

Marstek Venus E (5.12kWh), this plug-in model has gained a lot of popularity the last couple of months in some European markets like Belgium, Germany, and the Netherlands. It has a maximum charge rate of 2500W and can discharge at up to 2500W (should be connected to a separate power group and only if local regulations allow it). These kind of batteries plug into a regular AC socket and do not require an electrical inspection. But they aren't legal everywhere.

In my case, it's configured to track the readings of my digital electricity meter. The battery charges itself when my solar panels produce excess power and discharges when it detects grid consumption. Throughout the day, it buffers the intermittent solar power, and during the evening, night, and early morning hours, it keeps my grid power consumption close to zero.

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