Finding the Right Storage Size: From 800W Balcony Power Plant to 10kWp PV System

Mar 22, 2026

Choosing the right storage size for photovoltaic systems is crucial to increase self-sufficiency and achieve maximum savings. Whether it's an 800W balcony power plant or a 10kWp system – calculating PV storage size helps optimize self-consumption. A solar yield table allows for precise comparison of yields and cost savings.

Why calculating PV storage size is important

Correct sizing of the storage maximizes self-sufficiency and increases the self-consumption of solar power. Too small a capacity leads to unnecessary feeding into the grid, while too large a capacity causes unnecessary costs. According to market standards, the storage should comprise 1 to 1.5 kWh per kWp of PV power to achieve the highest economic efficiency.

For balcony power plants from 800W: 1-2kWh storage is the golden ratio for daily needs. For 10kWp systems, experts recommend 5-10kWh, as this provides the best cost-benefit ratio. This increases the degree of self-sufficiency from 30 percent without storage to up to 70 percent.

Calculation formula for storage size

The basic formula is: Storage capacity = night operation base load × desired reserve hours. Let's take a typical night load of 300W and 8 reserve hours: 300W × 8h = 2.4kWh of required storage. This method takes into account real household consumption and perfectly suits PV systems up to 10kWp.

For an 800W balcony power plant yield of around 700-900kWh per year, 1-2kWh of storage is ideal. For 10kWp with an annual yield of 10,000kWh, 5-10kWh is recommended to cover peak loads and maximize self-sufficiency. Adjust the formula to your location and consumption.

Market trends in solar storage

The market for PV storage is growing rapidly, with a focus on lithium-ion technology for higher efficiency. In Germany, installations are increasing by 40 percent annually, driven by falling prices and EEG subsidies. User profiles show: 60 percent of buyers are homeowners with 5-10kWp systems who want to increase their self-sufficiency.

Prices for 5kWh storage units are between 3,000-5,000 Euros, with amortization in 5-7 years. Balcony power plants with storage are booming among tenants, as plug-and-play solutions make entry easier. Regional yield differences influence storage choice: Southern Germany benefits from higher yields.

At DRBO Greenenergy, we pursue a clear goal: to advance the decentralized energy transition together with our customers. We already supply numerous hardware stores, specialist dealers, and installation companies with high-quality solar and energy storage solutions and now also support private customers with practical solutions.

Solar Yield Table: With and Without Storage

Here is an overview of annual yields and savings at 0.35 Euro/kWh grid electricity price.

PV Size	Yield without Storage (kWh/year)	Self-consumption without (%)	Yield with Storage (kWh/year, 70% self-sufficiency)	Annual Savings with Storage (Euro)
800W	800	30	560	140
2kWp	2,000	35	1,400	350
5kWp	5,300	40	3,700	925
10kWp	10,500	45	7,350	1,840

This solar yield table shows: With storage, savings double. For 10kWp, annual savings of 1,840 Euros are achieved compared to 472 Euros without storage.

Competitive Comparison: Storage for 10kWp

Criterion	5kWh Storage	10kWh Storage	Price (Euro)
Self-sufficiency rate	60%	75%	3,500/6,500
Charge cycles	6,000	8,000	-
Efficiency	95%	96%	-

10kWh models offer the highest cost-effectiveness for 10kWp systems, as they increase self-consumption by 30 percent.

Core technology: Increasing self-sufficiency

Lithium iron phosphate batteries dominate with 6,000 cycles and 95 percent efficiency. Intelligent energy management systems prioritize self-consumption and charge specifically during surplus. For balcony power plants, microinverters ensure stable storage charging.

The formula night load × hours gives precise sizes: For 800W, 1kWh is sufficient for 70 percent self-sufficiency. Combined with heat pumps, the degree increases further.

Application Examples and ROI

A tenant with an 800W balcony power plant saves 350 Euros annually with a 2kWh storage, with amortization in 3 years. For 10kWp in a single-family house: 7,000kWh self-consumption, ROI in 6 years. Real user story: "With storage, I cover 80 percent, bill has decreased."

PV Storage Buying Guide

Consider location, consumption, and subsidies. For 800W: 1-2kWh; 10kWp: 5-10kWh. Have it sized by specialists.

Future Trends in Storage Technology

By 2030, prices will drop by 30 percent, and solid-state batteries will increase capacity by 50 percent. Smart grids will further boost self-sufficiency.

Frequently Asked Questions

How large should the storage be for 10kWp?
5-10kWh for optimal economic efficiency and 70 percent self-sufficiency.

What is the annual yield of an 800W balcony power plant?
700-900kWh, with storage up to 600kWh of self-consumption.

How to increase self-sufficiency without storage?
By adjusting consumption and increasing efficiency by 10-20 percent.

PV storage size calculation app?
Use online calculators with consumption data.

Funding for solar storage?
KfW and regional subsidies up to 30 percent.

Sources

Energieheld.de: Calculate Photovoltaic Storage Size
Aceflex.de: Increase PV Self-Sufficiency
Photovoltaik.one: PV Yield Table 2026
Solarmotion.ch: Calculate Power Storage
Gruenes.haus: PV Storage Design
Regional-photovoltaik.de: Maximize Self-Sufficiency
Echtesolar.de: PV Tilt Angle Table
Basic-solar.de: Balcony Power Plant Storage Guide
Wegatech.de: Storage Calculator Sizing
Polarstern-energie.de: Increase PV Self-Sufficiency

Some of the information in this article comes from the internet. Product specifications may be updated at any time. For the latest information, please visit the official website or product page.