The Connection between Inverter Auto Transfer Switch and Batteries

The automatic transfer switch of an inverter, which is a crucial feature, facilitates the switch between different power sources.

  • In a photovoltaic system, solar energy is robust, and the battery gets charged, the inverter converts the direct current produced from the solar panels into alternating current for the usage of electrical appliances. The automatic transfer switch of the inverter gets set to solar power mode.
  • However, during times when the sunlight is insufficient, or at night with the absence of the sun, the battery provides power to the home. The automatic transfer switch of the inverter switches to battery power mode.
  • Making it handy for powering electrical appliances when the battery runs out. And, to ensure no interruption in power supply, the inverter automatically switches to the grid power mode.

Overall, the working principle of an inverter automatic transfer switch is actually based on power supply, and the battery plays a role in energy storage and supply in this process.

inverter auto transfer switch

Exploring the Commonly Used Lithium Batteries for Inverters

Market research shows that lithium batteries are increasingly favored by inverter systems due to their excellent energy density, long cycle life, and low maintenance requirements.

DC coupled inverter with battery

Below are some commonly used inverter lithium batteries:

48V lithium battery: 48V lithium batteries are very common in the inverter market because they provide stable and reliable power output. The key to this kind of battery is to choose a reliable brand, because the difference in quality may directly affect the performance and life of the battery.


Solar lithium battery: For devices that need to store a large amount of energy (such as inverters), solar lithium batteries are the ideal choice. This is mainly due to the high energy density and long life properties of lithium batteries.


Dedicated inverter lithium battery: Some lithium batteries may need specific inverters to be compatible, this is because the inverter needs a function that can communicate with the battery.

Therefore, when choosing batteries and inverters, it is necessary to check whether they are compatible. 

Since most residential PV systems are currently fixed and the relocation requirements for batteries are not very high, and in order to match various brands and models of inverters on the market, the most commonly used at present is still the 48V lithium battery

Lithium batteries are widely used in inverters for the following main reasons:

Great energy density: The energy density of lithium batteries is much higher than that of lead-acid batteries, which means they can store more energy in a smaller volume. This is very attractive for inverter systems that need a large amount of energy.

Long life: Lithium batteries have an ultra-long lifespan, making them an ideal choice for power systems, especially in inverter systems that need to rely on long-term battery storage.

High voltage output: Lithium batteries have a higher voltage output, enabling them to drive a variety of types of electronic devices, including inverters. In this way, users can use a variety of electrical appliances without having to worry about insufficient power.

Small size and high energy: As lithium is a highly active element, lithium battery inverters can store a large amount of energy in a small space. This makes the design more compact, easy to carry and install.

Low self-discharge rate: Compared to other types of batteries, lithium batteries have low self-discharge rates, meaning that when the battery is not being used, it consumes less power. This is very useful for devices that need to store and use energy for a long time, such as inverters.

solar panel

Deep Dive into 48V Lithium Batteries: composition of the Module battery for 48V li-ion battery

In examining lithium-ion or lithium iron phosphate batteries, the voltage is usually 51.2V.

This is because the single battery voltage for lithium batteries is usually 3.2V, and to achieve a system voltage of 48V, 16 single batteries need to be connected in series, thereby obtaining 16 x 3.2V = 51.2V.

The so-called "48V" is actually the normal operating voltage of lithium-ion battery group, hence often referred to as the "48V system". In practice, however, the actual voltage is 51.2V.

The 48V lithium battery systems are quite common in battery modules, mainly due to the following reasons:

Compatibility: 48V lithium battery systems can typically directly replace the old lead-acid battery systems due to their similar system voltage. This facilitates upgrading the existing lead-acid battery system without having to replace other components.

Safety: Compared to high voltage systems, 48V offers a relatively low voltage, thus increasing its safety. Low voltage systems pose less danger in case of battery failure.

Efficiency: Losses in low voltage systems are usually lower, and the efficiency is higher.

Cost: In comparison to high voltage system designs, the design and manufacturing costs of control and protective circuits for 48V systems are lower.


battery cell

Because of these advantages, 48V li-ion battery systems are suitable for small-scale home photovoltaic storage systems as well as mobile energy storage devices like electric vehicles. They offer a good balance of sufficient energy storage, safety, and efficiency.

Step-by-Step Guide on Charging 48V Lithium Batteries

  •        Safety Check: Ensure that the battery, Battery Management System (BMS) and the charger show no signs of physical damage. The workspace should be dry, clean and well ventilated.
  •        Connect the Battery: First, turn off the battery switch if there is one, then connect the charger's power cord with the battery's charging line, ensuring a safe and secure connection.
  •        Connect the Charger: Plug the charger into an appropriate power socket, based on the setting, initiate the charging process. Most chargers have indicator lights displaying the charging status via colours or blinking states.
  •        Keep An Eye On The Charging Process: During charging,regularly check the battery's condition, observing any overheating, smoke or other anomalies.
  •        Confirm Fully Charged: When the charger's indicator light shows that the battery is fully charged, or for batteries with a BMS, when the BMS indicates that the battery is full, you can cease charging.
  •        Disconnect Charger: Firstly, disconnect the charger from the power socket, then disengage the connection between the battery and charger.
  •        Store Battery: If the battery isn't immediately required, store it in a dry, cool place.

The Key Role of Proper Charging in Maintaining and Optimising Lithium Batteries in Inverters

Lithium batteries, an important part of any power backup system, work by storing energy and releasing it when necessary. One key point to remember is that the way lithium batteries get charged greatly affects their lifespan.

Importance of Proper Charging

To maintain the functioning and prolong the lifespan of lithium batteries, it's essential to charge them properly. This entails using the correct charger, setting up the right charging parameters (which depend on the specific battery model), and monitoring the charging process to avoid overcharging.

Charging Parameters

The charging of lithium batteries typically involves two stages: the constant current mode and the constant voltage mode. In the constant current mode, the charger supplies the battery with a constant current. Once the battery voltage hits a specific threshold value, the charger switches to the constant voltage mode, decreasing the charging current while keeping the voltage constant until the battery is fully charged.

Effects of Overcharging and Undercharging

Overcharging can cause lithium batteries to degrade faster, reducing their overall lifespan. On the other hand, undercharging batteries leads to insufficient stored energy, and thus, inconsistent power supply. Therefore, a balance must be found to ensure correct charging.

By following these principles, you can make sure your lithium battery storage system delivers the best performance and gets the maximum lifespan.

Operational Regulations for Inverters and Battery Systems

Safe Operation

The safe operation of rechargeable inverters and battery systems is crucial in any setting. Always follow these guidelines:

  •        Avoid operating in high temperature, high moisture, or dusty environments.
  •        Do not cover the ventilation holes on the devices.
  •        Disconnect the charger from power sources when not in use.
  •        Avoid touching the battery connections and inverter terminals with bare hands to prevent electric shock.
  •        In case the battery leaks and the liquid gets into the eye, do not rub one's eyes and rinse them with clean water, and go to see a doctor in serious situation.

Maintenance and Inspection

  •        Regularly clean the devices, making sure they are dust-free.
  •        Inspect the devices for any sign of physical damage. If damage is found, they should be repaired or replaced immediately.
  •        Check if the charging cables and connections are well secured and insulated.
  •        Rules for Handling Battery
  •        Misoperation can cause battery leaks, hit, shock, or even explode, so we must follow the rules strictly.
  •        Do not disassemble or reconstruct the battery.
  •        Do not put the battery in microwave ovens, high-pressure containers, or on induction cookware.

Conclusion: The important role of correctly charged batteries in the whole process

In previous information, we discussed why lithium batteries are widely used in inverters. The long lifespan, high energy density, high voltage output, small size, and low self-discharge rate of lithium batteries make them an ideal choice for inverters.

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