Buying a solar power storage unit: Pay attention to these tips!

Independent with self-generated solar power. Conscious about the environment and the future. There are many reasons why more and more people are buying a solar power storage unit. Before acquiring a solar power storage unit, you should consider the following tips.

1. Tip: Choose the correct battery type

The centrepiece of every power storage unit is the battery. It is, therefore, recommended that you take a close look at the battery technology when buying a power storage unit. Lead-acid, gel lead-acid, and lithium-ion based batteries have a high market share in the power storage sector.  Lead-acid based batteries have a lower purchase price than lithium-ion based batteries. They also have lower efficiency and shorter service life. During operation, the perceived purchase price benefit quickly turns into a disadvantage. Compared with lithium-ion based batteries, lead-acid based batteries have a negative life-cycle assessment due to their short service life and use of heavy metals. Lithium-ion and lithium-iron-phosphate based batteries have significantly higher efficiency when compared with lead-acid based ones. Among the types of lithium-ion based batteries, lithium-iron-phosphate batteries have the added benefit of being safer from fire hazards. They bind oxygen better and have a lower energy density. They also feature a long cycle life and high efficiency.

2. Tip: Pay attention to efficiency

When you acquire a solar power storage unit, it pays off to look out for overall efficiency. It is an indicator value of how efficiently energy is converted within the unit.  The higher the efficiency, the lower the energy loss when storing and converting the electricity. Power storage control units will also cause losses.  A variety of different efficiency rates are in use. They make an initial comparison between systems confusing and hard.  To create more transparency, HTW Berlin has developed a System Performance Index (SPI). This index makes it easy to compare the overall performance of different solar power storage systems. The SPI for your selected system should ideally be over 90 per cent.

3. Tip: Check the depth of discharge

Looking at the depth of discharge of a storage system, you can determine the proportion of the nominal storage capacity that can be extracted during operation. Typical values range between 50 and 90 per cent. They should ideally not exceed 90 per cent to safeguard long battery life.

4. Tip: Choose the right solar power storage unit size

There are essentially two main factors that determine the dimensioning of your solar power storage unit: the size of your PV system and your electricity consumption. The higher the installed PV capacity and electricity consumption, the larger the solar power storage unit. RCT Power has, therefore, developed a flexible battery size range. The nominal capacities range from 3.8 kWh to 11.5 kWh and can be retrofitted on a modular basis. The chosen unit size should support your goal to achieve the highest degree of self-sufficiency.

5. Tip: Measure space requirements

Solar power storage units come in different dimensions and shapes. Before you decide to buy one, it is recommended that you establish where it will be located and the amount of space it can occupy. Take measurements of height, width and depth at a chosen location, ensuring that the ambient temperature is between 15 and 25 °C. Compact sized storage units usually have a smaller footprint than some of the larger models on the market. The manufacturer's datasheets will provide you with the exact external dimensions.

6. Tip: Consider backup power functionality

Good solar power storage systems are equipped with back-up power functionality. If there are short term or long term power outages caused, for example, by storms or damaged supply lines, a so-called Power Switch will in a matter of seconds connect your household to back-up power from your solar power storage system. In times when homes are increasingly used for office purposes, back-up power can not be underestimated.

Conclusion: Buying a solar power storage unit

Buying a solar power storage unit is becoming increasingly beneficial. If you do buy one, make sure you select modern battery technology and consider future use scenarios. Subsidy programmes will make it even more attractive to acquire a solar power storage system.Get individual advice from our specialist partners and let them help you select the right energy storage device for your home.