The Indication of kWh For Lithium Batteries Solar Power Storage

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What Does The Indication of kWh Mean for Lithium Batteries Solar Power Storage?

If you want to purchase batteries solar power storage for your photovoltaic system, you should find out about the technical data. This includes, for example, the specification kWh.

What is The Difference Between Kilowatts & Kilowatt-hours?

Watt (W) or kilowatt (kW) is the unit of measurement of electrical power. It is calculated from the voltage in volts (V) and the current in amperes (A). Your socket at home is usually 230 volts. If you connect a washing machine that draws 10 amps of current, the socket will provide 2,300 watts or 2.3 kilowatts of electrical power.

The specification kilowatt-hours (kWh) expresses how much energy you use or generate within an hour. If your washing machine runs for exactly one hour and constantly draws 10 amps of electricity, then it has consumed 2.3 kilowatt-hours of energy. You should be familiar with this information. Because the utility bills your electricity consumption according to kilowatt-hours, which the electricity meter shows you.

What Does The Specification kWh Mean for Electricity Storage Systems?

In the case of a solar power storage system, the kWh figure shows how much electrical energy the component can store and then release again later. You have to differentiate between the nominal capacity and the usable storage capacity. Both are given in kilowatt-hours. The nominal capacity specifies how many kWh your electricity storage can in principle store. However, it is not possible to use them completely. Lithium ion batteries for solar power storage have a deep discharge limit. Accordingly, you must not empty the memory completely, otherwise, it will be broken. The usable storage capacity is around 80% of the nominal capacity.

Solar power storage batteries for photovoltaic systems (PV systems) work in principle like a starter battery or car battery. When charging, a chemical process takes place, which is reversed when discharging. The materials in the battery change over time. This reduces the usable capacity. After a certain number of charge/discharge cycles, the lithium battery storage systems no longer function.


In industrial applications, for example, the following battery power storage systems are used as an uninterruptible power supply (emergency power):

Power storage with 1000 kWh

Power storage with 100 kWh

● Power storage with 20 kWh

Every data center has huge battery storage systems since a power failure would be fatal and very large amounts of electricity would be required to maintain operations.


Home UPS power supply for solar, for example:

Power storage with 20 kWh

10kWh Powerwall Battery 48V

Power storage with 6 kWh

Power storage with 5 kWh

Electricity storage with 3 kWh

The smaller the kilowatt-hours, the less electrical energy these solar power storage batteries can hold.

Lead batteries and lithium-ion storage systems, which are widely used in electronics and electromobility, are primarily used as home storage systems. Lead-acid batteries are cheaper, but have a shorter lifespan, tolerate fewer charge/discharge cycles, and are less efficient. Because part of the solar energy is lost when charging.

Which Performance is Suitable for Which Residential?

A rule of thumb for the living area says that the capacity of the battery storage should be around 1-kilowatt hour per 1-kilowatt peak (kWp) output of the installed photovoltaic system. Assuming that the average annual electricity consumption of a family of four is 4000 kWh, the corresponding peak solar installed output is about 4 kW. Therefore, the lithium battery storage capacity of solar energy should be around 4 kWh.

In general, it can be deduced from this that the capacities of the lithium battery solar power storage in the home sector are between:

● 3 kWh (very small home, 2 residents) up to

Can move 8 to 10 kWh  (in large single and two-family houses).

In multi-family houses, the storage capacities range between 10 and 20kWh.

This information is derived from the rule of thumb mentioned above. You can also determine the size online with a PV storage calculator. For the optimal capacity, it's best to contact a BSLBATT expert who will calculate it for you.

Apartment tenants are usually not faced with the question of whether they should use a home storage system for solar power, as they only have a small photovoltaic system for the balcony. Small lithium battery storage systems are more expensive per kWh of storage capacity than larger devices. Therefore, such a lithium battery storage facility is unlikely to be worthwhile for tenants.

Electricity Storage Costs According To kWh

The price for electricity storage is currently between 500 and 1,000 Dollars per kWh of storage capacity. As already mentioned, smaller lithium battery solar storage systems (with lower capacity) are usually more expensive (per kWh) than larger lithium battery solar storage systems. In general, it can be said that products from Asian manufacturers are somewhat cheaper than comparable devices from other suppliers, for example, the BSLBATT solar wall battery.

The costs for lithium battery storage per kWh also depend on whether the offer is only about storage or whether the inverter, battery management and charge controller are also integrated. Another criterion is the number of charging cycles. A solar power storage device with a lower number of charging cycles is more likely to have to be replaced and is ultimately more expensive than a device with a significantly higher number.

In recent years, the cost of electricity storage has fallen rapidly. The cause is the higher demand and the associated efficient industrial production of larger quantities. You can assume that this trend will continue. If you put off investing in lithium battery storage for a while, you may be able to benefit from lower prices.

Advantages and Disadvantages of Lithium Battery Storage Systems for Solar Systems

Are you unsure whether you should buy a PV domestic power storage system?

Then the following overview of the advantages and disadvantages will help you.


1. Expensive Per kWh

With around 1,000 Dollars per kWh of storage capacity, the systems are quite expensive.

BSLBATT SOLUTION: Fortunately, the price of lithium batteries for solar power storage launched by BSLBATT is relatively cheap, which can meet the power needs of housing and small businesses with tight funds!

2. Inverter Matching is Difficult

It is all the more important that you choose the optimal model for your PV system.  On the one hand, the lithium battery storage device must match the system, but on the other hand, it also has to match the power consumption of your household.

BSLBATT SOLUTION: The BSL solar wall battery is compatible with SMA, SolarEdge, Sungrow, Huawei, Victron Energy, Studer, Growatt, Sofarsolar, SolaX, Voltronic Power, Deye, Goodwe, East, Fronius Solar Energy, Sunsynk. And our lithium battery energy storage system provides solutions from 2.5-2MWh, which can meet the electricity needs of a variety of residential, enterprises, and industries.

3. Installation Restrictions

An electricity storage system not only requires space. The installation site must also offer optimal conditions. For example, the ambient temperature should not be above 30 degrees Celsius. Higher temperatures have a detrimental effect on service life. High humidity or even wetness is also unfavorable. In addition, the floor must be able to bear the heavyweight.

BSLBATT SOLUTION: We have a variety of lithium battery modules such as wall-mounted, stacked, and roller-type, which can meet a variety of usage scenarios and environments.

4. Power Storage Life

The life cycle assessment in the production of electricity storage systems is more problematic than with PV modules. The modules save the energy used in their production within 2 to 3 years. In the case of storage, it takes an average of 10 years. This also speaks in favor of choosing memories with long service life and a high number of charging cycles.

BSLBATT SOLUTION: Our lithium battery home energy storage system has more than 6000 cycles.


By combining your photovoltaic system with batteries for solar power storage, you can significantly increase your own photovoltaic consumption and improve the sustainability of photovoltaics even more.

While you only use around 30 percent of your solar power yourself without lithium batteries for solar power storage, the proportion increases to 60 to 80 percent with a lithium solar storage system. The increased self-consumption makes you more independent of price fluctuations at the public electricity suppliers. You save costs because you have to buy less electricity.

In addition, the high level of self-consumption means that you use much more climate-friendly electricity. Most of the electricity provided by the public electricity suppliers still comes from fossil-fuel power plants. Its production is linked to the emission of a large amount of the climate killer CO2. So you contribute directly to climate protection when you use electricity from renewable energies.

About BSLBATT Lithium

BSLBATT Lithium is one of the world's leading lithium-ion batteries solar power storage manufacturers and a market leader in advanced batteries for grid-scale, residential storage and low-speed power. Our advanced lithium-ion battery technology is the product of over 18 years of experience developing and manufacturing mobile and large batteries for automotive and energy storage systems (ESS). BSL lithium is committed to technological leadership and efficient and high quality manufacturing processes to produce batteries with the highest levels of safety, performance and reliability.