Balcony solar power stations, also known as mini-PV systems, are small "balcony power plants" that typically consist of a few PV modules. These modules are installed on balconies, house facades, terraces, gardens, or garages or carports, and are directly connected to a special power outlet and your apartment circuit via a micro-inverter. The working principle of this micro PV system is the same as that of a "large" PV system on the roof: it converts incident sunlight into current and feeds it into your home. Every appliance in your home (whether it is a dishwasher, oven, or refrigerator) first uses "its own electricity" before drawing electricity from the public grid.

Balcony Solar Power Plant with Battery Storage

Above intelligent battery in picture is the MicroBat 2.5kWh

Balcony photovoltaic storage system, as the name suggests, is to add a battery system between PV modules and micro inverters. The purpose is to maximize the power generation of solar panels, and through the intelligent control of the discharge process, it can discharge at different power levels in different time periods, and distribute 100% of solar generation to achieve solar self-consumption, so as to avoid feeding into the grid without any benefits.

The calculation of the system cost and ROI of a balcony solar power plant without storage

As shown in the table below, these are the final retail prices of balcony solar power stations in an online store as a reference.

Example of a minimum solar system

Balcony Solar Power Plant with Battery Storage 1

For a 375W balcony PV system, the self-consumption rate can be as high as 80% due to its small capacity. Based on experience, the annual power generation of this system is about 375kWh. Therefore, the annual electricity cost savings can be calculated as follows:

375kWh x 80% x 0.28 Euros = 84 Euros

Taking into account other costs, the investment can be recouped in about four years. Of course, this system is very small and cannot cover the annual electricity consumption of a household.

Example System 2

For a 750W balcony solar system, the self-consumption rate can typically be as high as 60%. Based on experience, the annual power generation of this system is about 750kWh. Therefore, the annual electricity bill savings can be calculated as follows:

750kWh x 60% x 0.28 Euros = 126 Euros

Taking into account other costs, the investment can be recouped in about six years.

Example System 3

For an 810W balcony PV system, it is assumed that the self-consumption rate of a mini PV system exceeding 800W is only 50%. Based on experience, the annual power generation of this system is about 820kWh. Therefore, the annual electricity bill savings can be calculated as follows:

820kWh x 50% x 0.28 euros = 114.8 euros

Taking into account other costs, the total investment is calculated to be 750 euros. The investment can be recouped in about 6 to 7 years.

However, it is worth noting that the peak electricity consumption for most apartments occurs in the evening after work, while the electricity consumption during the day is only for a small load, such as a refrigerator and a router, about 200W to 300W. In this case, the actual self-consumption of electricity is lower. The payback period of the investment will be longer.

Calculation example of balcony solar power station with built-in battery storage system

A high self-consumption rate is essential for the economic operation of a solar system. This can be achieved by optimizing the use of household appliances, heating (for example, heat pumps), or charging electric vehicles during sunny periods. Of course, excess solar energy can also be stored in a battery storage system to achieve a higher self-consumption rate.

For small balcony power plants with an output power of 300W, the use of a storage system is not meaningful, as experience shows that the self-consumption rate is 80-90%. Even for large balcony solar power plants with an output power of 600W, the use of a storage system is not worth it, as direct self-consumption is still 60-80%.

However, when the total installed power of the solar modules exceeds 800W or even more, and the electricity consumption time is in the evening or morning, when there is no solar energy or solar energy generation is insufficient, the use of a battery storage system can improve the economic efficiency of the solar system.

The self-consumption rate of solar energy is about 50% or even lower. At this time, we consider the possibility of adding a battery storage system.820kWh / 365 = 2.24 kWh/day.The daily power generation of a 820W solar panel is 2.24 kWh. Therefore, the solar battery storage capacity for solar energy storage should be around 2 kWh to ensure generation peak shifting. When the retail price of a battery is around 750 euros, and the battery storage can meet at least a 50% self-consumption rate for solar energy, then it is worthwhile to install battery storage in a balcony PV system.

Another calculation based on VDE new rules a trivial limit of up to 800 W

As is well known, the core value of balcony solar systems lies in their ease of installation and quick grid connection through a Wieland or Schuko plug. VDE has released a new rule that allows the use of a Schuko plug as a plug-in device for the supply of up to 800 W. If we assume that a balcony PV system can continuously output 800W of power for 24 hours, then the total output is 19.2 kWh. Of course, this is not a realistic power output. From the following diagram, we can assume that the annual electricity consumption of a two-person household in Germany is 2,500 kWh.

Balcony Solar Power Plant with Battery Storage 5

Therefore, the daily electricity consumption is 2500 kWh / 365 days = 6.85 kWh. So, can we assume that for a one- to two-person household, a mini PV system that generates 4 to 8 kWh per day, and a battery storage system that shifts the peak generation by 2.5 to 5 kWh, can almost achieve 100% solar self-consumption.

Based on the above data, the configuration of a balcony solar storage system is as follows:

3 pcs 410W PV modules, 2.5kWh balcony battery storage and 800W micro inverter can produce about 4 kWh of electricity per day and achieve demand shifting.

8 pcs 410W PV modules, 5kWh balcony battery storage and 800W micro inverter can produce about 8 kWh of electricity per day and achieve demand shifting and solar self-consumption.

In conclusion, for balcony PV systems with a power output of more than 800 W, it is possible to achieve 100% self-consumption through battery storage and programmable output. However, the actual self-consumption rate will vary depending on the household's electricity consumption habits.

Batterlution micro battery storage solution for balcony mini selfPV power plant

MicroBat 2.5kWh

Batterlution Balcony Power Plant Battery Storage is a plug-and-play system that uses LiFePO4 batteries to store excess solar energy from your balcony solar panels. It has dual built-in MPPT controllers and a maximum 800W limited programmable DC output. The batteries are compatible with 99% of micro inverters in the market.

balcony-solar-storage-2.3kwh-2.1

Key features:

  • Plug-and-play system for easy installation
  • LiFePO4 batteries for long life and durability
  • Dual built-in MPPT controllers for maximum efficiency
  • Maximum 800W limited programmable DC output
  • Compatible with 99% of micro inverters

Benefits:

  • Store excess solar energy from your balcony solar panels
  • Reduce your electricity bills
  • Increase your self-sufficiency
  • Protect your home from power outages
  • Environmentally friendly solution

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