Inverter Battery SOC Function Setting Guide

What is the function of the inverter's battery SOC function setting?

The battery SOC setting (State of Charge) in the inverter refers to the parameter configuration that finely manages the battery's charging and discharging behavior, working mode switching, and safety protection by presetting the battery's remaining power percentage (%). Generally speaking, it can be simply understood as the battery's "remaining power percentage", just like the battery level display of "30%" or "80%" on a mobile phone. The SOC setting of the inverter is essentially to make the battery more durable and the power supply more stable in different scenarios by presetting the "critical power point". The SOC setting is only effective for lithium battery, while lead acid batteries must rely on voltage parameters for control and have no direct SOC operation.

Inverter SOC setting function description

Take the introduction of Xindun HFP-C hybrid inverter as an example. There are seven SOC setting operations in the inverter function setting, including shutdown SOC, low voltage recovery SOC, inverter to mains battery SOC, mains to inverter battery SOC, and charging cut off SOC settings. These are the five conventional SOC settings. Since Xindun HFP-C hybrid inverter has intelligent dual output function, the other second SOC settings are additional settings for this function (intelligent dual output function output voltage/recovery SOC settings). All SOC settings of the inverter must be effective after communicating with the lithium battery before they can be set.

Shutdown SOC setting

When the battery power drops to the set value (such as 10%), the inverter will automatically shut down to avoid over discharge and damage to the battery.

Low voltage recovery SOC setting

After the battery is shut down due to low power, the inverter will resume inverter power supply when it is charged to the set value (such as 15%) to avoid shutting down again after the battery is exhausted.

Inverter to AC battery SOC setting

When the inverter is in "battery priority output" mode, when the battery power drops to the set value (such as 15%) and the AC power is normal, it will switch from battery inverter power supply to AC power supply to avoid battery exhaustion.

AC to inverter battery SOC setting

When the battery is charged under AC power supply and the power is charged to the set value, it will automatically switch back to battery inverter power supply from AC power supply.

Charging cut off SOC setting

When the battery power is charged to the set value (such as 95%), the inverter will automatically power off and stop charging to avoid battery overcharge.

Intelligent dual output function output voltage SOC setting

Xindun HFP-C hybrid inverter has intelligent dual output function. The SOC needs to be turned on before it can be set. After it is turned on, when the battery power drops to the set value (such as 15%), the inverter will automatically turn off the main output (non critical loads, such as air conditioners, TVs, etc.), and only retain the second output (such as refrigerators, lighting, etc.) to ensure that key equipment is not disconnected and continue to supply power to loads.

Smart dual output function output recovery SOC setting

Similarly, the SOC also needs to be turned on before the smart dual output function can be set. After it is turned on, when the battery power is charged to the set value (such as 70%), the inverter restores the main output, and the main output continues to supply power normally. This SOC setting is to balance the power supply requirements of the second output (critical load) and the main output (non critical load).

Different SOC settings play an important synergistic role in actual use, which can effectively protect the battery from overcharging, and at the same time restore power supply in time when the power is restored. When encountering power outages and other situations, the SOC setting not only ensures the inverter's flexible switching between battery power and city power, but also avoids excessive battery discharge. The damaged battery can be used at the right time, which can make efficient and reasonable use of the battery and extend the battery life.

The two SOC settings of the intelligent dual output function of the Xindun HFP-C hybrid inverter ensure the continuous power supply of key load equipment under special circumstances and meet the power supply needs of users for different load equipment. When using, users need to reasonably set each SOC according to their actual power consumption and battery characteristics. The specific operation and function of the SOC setting of inverters of different brands and models may be different, but the basic principle and purpose are to better manage the charging and discharging of the battery and improve the efficiency and safety of the battery.

How to set and use the inverter SOC in hybrid mode?

Taking the Xindun HFP-C solar inverter as an example, this inverter is a hybrid inverter that can be set to three modes: hybrid, off grid, and on grid. Among them, the hybrid mode and off grid mode require access to a battery to operate, and the battery must be a lithium battery type to set the SOC.

Due to the limited length of the article, Xindun will next give you a detailed introduction on how to set and use the inverter's SOC setting in the hybrid mode (for reference only, users need to operate and set according to actual conditions).

Hybrid mode

In the hybrid mode, the mains is available, and the battery is used as an intermediate buffer. The charging priority determines the energy source for battery charging, such as PV as the main, the mains as the auxiliary, or only PV. The inverter's SOC setting needs to adapt to the charging efficiency and load switching requirements.

1. Charging priority SNU mode (PV and mains are charged at the same time, PV are consumed first)

In this mode, PV are charged first, and the mains are supplemented when the power is insufficient. The charging speed is fast and the battery is easy to be fully charged. It is suitable for scenes with sufficient light resources and relatively stable mains (such as rural suburban families). Due to the dual charging sources of PV and mains, there is no need to be overly conservative. The battery power can be fully utilized, and the mains can be used as a backup to avoid over discharge of the battery.

SOC setting suggestions

Charging cut off SOC: The inverter defaults to 100%, but it can be set to 90% - 95% in high temperatures in summer to avoid the risk of high temperature when fully charged. Due to sufficient charging sources, PV and mains can be fully utilized to charge the battery and reserve energy to cope with temporary interruption of mains.

Shutdown SOC: can be set to 5% - 10% (default value 5%). In hybrid mode, there is mains to back up. Even if the battery is discharged to this SOC value, there is also mains to quickly replenish it. There is no need to reserve too much power, and the battery discharge efficiency can be maximized and fully utilized.

Low voltage recovery SOC: can be set to 15% (default value). In SNU charging mode, the dual energy (PV+AC) charges quickly. When the battery power is charged to 15%, the inverter can resume inverter output, reducing the inverter downtime, which is suitable for scenarios with high load continuity requirements (such as daily household electricity consumption).

Inverter to AC SOC: In battery priority output mode: can be set to 10% - 15%. When the battery is discharged to this set value, the AC is switched on, which can not only avoid over discharge of the battery, but also use the AC as a backup, which is suitable for non critical loads (such as air conditioners).

AC to inverter SOC: In battery priority output mode, it can be set to 70% - 75%. Because the battery charges quickly in SNU charging mode, there is no need to wait for full charge. When it is charged to 70%, it can be switched back to battery power supply, reducing dependence on AC power.

Intelligent dual output (on): The main output shutdown SOC can be set to 15% (default value), and the main output recovery SOC can be set to 70%. Because the battery charges quickly in SNU charging mode, the main output recovery threshold can be set slightly lower, which can take into account the use of non critical load equipment of the second output.

2. Charging priority - OSO (PV charging only, mains not involved in charging)

In this mode, only PV charging is relied on, and the charging speed is greatly affected by light (fast on sunny days, slow on rainy days). More power needs to be reserved to cope with light fluctuations to avoid over discharge of the battery. It is easy to lose power when there is no mains supplement. It is suitable for scenes with sufficient light (such as remote pastoral areas, rural self built houses, etc.).

SOC setting suggestions

Charging cut off SOC: can be set to 100%. Because there is no mains supplement, it is necessary to maximize the use of PV to fully charge the battery and reserve energy to cope with night or rainy days.

Shutdown SOC: can be set to 12% - 15% (higher than the default value of 5%). To avoid over discharge of the battery when there is insufficient light and no mains supplement, a certain amount of power needs to be reserved to maintain the continuous operation of key loads (such as lighting, monitoring, etc.).

Low voltage recovery SOC: 20% - 25% (higher than the default value of 15%). The PV charging speed is slow, and it is necessary to charge to a higher SOC before resuming output, reduce frequent start and stop, and avoid repeated shutdowns caused by light fluctuations.

Inverter to mains SOC: 15% - 20% (if mains emergency is allowed). If mains switching is allowed in extreme cases, the switching threshold needs to be increased, and batteries should be used as much as possible.

Mains to inverter SOC: can be set to 80%. If mains power is used occasionally for supplementary power, it needs to be charged to 80% before switching back to the battery, making full use of mains power replenishment and reducing subsequent dependence.

If the SOC is in off grid mode because there is no mains access, the function of the SOC will not work, so keep the default value (80%). If the user can access mains power for supplementary power, 85% can be set to provide a more suitable buffer for switching from mains power to inverter power supply, ensuring that when the mains power supply is unstable or interrupted, the inverter can take over the power supply more promptly and stably, ensuring the continuous operation of key load equipment. At the same time, such a setting can also avoid frequent power supply switching to a certain extent, reduce the impact on the equipment, and extend the service life of the equipment.

Intelligent dual output (on): The main output shutdown SOC can be set to 20%. The main output needs to be shut down in advance to stop non critical loads from carrying loads. The main output recovery SOC can be set to 80% (after ensuring that the PV battery has sufficient battery power, the main output power supply is restored). Because PV charging is slow, it is necessary to prioritize the continuous power supply of key load equipment (such as refrigerators, lighting, etc.) of the second output.

3. Charging priority - CSO (PV priority, when there is no PV, the main power will intervene to supplement)

When there is sufficient sunlight, pure PV charging is used, and on rainy day/night, the main power is supplemented. The charging stability is between SNU and OSO, which is suitable for use in scenarios with medium sunlight and available main power.

SOC setting suggestions:

Charging cut off SOC: can be set to 95% - 100%. When there is sufficient PV power, the battery can be fully charged. When there is no PV power, the main power will intervene to charge. In this mode, there is no need to deliberately limit full charging.

Shutdown SOC: can be set to 8% - 10% (slightly higher than SNU mode). When there is no PV power, the mains can be charged, and there is no need to be overly conservative, but deep discharge of the battery should be avoided (slightly higher than SNU mode, to balance the battery life).

Low voltage recovery SOC: can be set to 15% - 20%. When PV power is insufficient, the mains can quickly replenish power, and the recovery threshold does not need to be too high, and the continuity of power supply should be taken into account.

Inverter to mains SOC: can be set to 13%. Higher than SNU (10%) and lower than OSO (15%), PV power is used first, and the mains is switched when it is almost exhausted (balanced between cost and experience)

Mains to inverter SOC: can be set to 70% (lower than the default value of 80%). Because the mains can replenish power, the battery can be switched back to the battery inverter power supply when it is charged to 70%, reducing the use of mains power and reducing the mains electricity fee.

Intelligent dual output function (on): The main output shutdown SOC can be set to 15% (default value), and the main output recovery SOC can be set to 75%. Because the mains can assist in recovery, the threshold for main road recovery is slightly lower than that of the OSO mode, taking into account the use of non critical loads output by the mains.

The setting of the inverter SOC has different characteristics and applicable scenarios for different charging priorities in the hybrid mode. The SNU mode is suitable for areas with sufficient light resources and stable mains, and can quickly charge the battery; the OSO mode is suitable for scenarios with high mains costs and sufficient light, and can maximize the use of PV power; while the CSO mode takes into account both PV and mains, has good stability, and is suitable for situations with medium light and mains available.

The above SOC setting suggestions are for reference only. In actual use, users need to flexibly adjust the various setting parameters of the inverter SOC based on factors such as light conditions, mains stability, electricity costs, and load types and needs. In addition, the settings should be optimized and set according to the actual performance of the battery to avoid damage to the battery caused by overcharging or over discharging.

How to set up and use the inverter SOC in off grid mode?

Next, Xindun will give you a detailed introduction on how to set and use the inverter's SOC setting in off grid mode (for reference only, users need to set it according to actual conditions).

Similarly, taking the Xindun HFP-C solar inverter as an example, in off grid mode, the battery charging priority determines the energy source for battery charging. Both PV and mains charging will directly affect the battery charging speed and stability. The Xindun HFP-C hybrid inverter adjusts the SOC setting in combination with the charging priority. In off grid mode, with the supplement of mains, the battery charging will be more stable, and the inverter's battery SOC setting can make full use of the power; in scenarios without mains, the battery charging is more dependent on PV, and the SOC setting needs to reserve more surplus power.

1. Charging priority - OSO (PV charging only, mains does not participate in charging)

The OSO charging mode is completely dependent on PV charging, without mains supplement, and the charging speed depends on the light, which is also greatly affected. It is suitable for scenes with abundant and stable light. In off grid mode, the battery needs to be used sparingly, and the SOC setting reserves more surplus power to cope with insufficient light to avoid the battery from being completely depleted.

SOC setting suggestions:

Charging cut off SOC: can be set to 100%. PV energy must be stored to the maximum extent to cope with power supply at night or on rainy days.

Shutdown SOC: can be set to 20%. To avoid excessive discharge of the battery, when selecting this charging mode, there is no backup source of mains power, and power must be reserved for key load equipment to avoid direct power outage.

Low voltage recovery SOC: can be set to 30%-40%. PV charging is slow, and it is necessary to charge to a sufficient amount of power (more than 30%) before resuming output to ensure that the power is sufficient to support a period of time to avoid shutting down again due to weakened light just after startup.

Inverter to mains SOC: If the SOC is in off grid mode due to no mains access, the function of the SOC will not work, so keep the default value (10%). If the user can access the mains to supplement, it can be set to 20% to provide a certain buffer power for the system to switch to the mains.

Mains to inverter SOC: If the SOC is in off grid mode and there is no mains access, the function of the SOC will not work, so keep the default value (80%). If the user can access the mains to supplement, it can be set to 85% to provide a more suitable buffer for the switch from mains to inverter power supply, ensuring that when the mains power supply is unstable or interrupted, the inverter can take over the power supply more promptly and stably to ensure the continuous operation of key load equipment. At the same time, such a setting can also avoid frequent power supply switching to a certain extent, reduce the impact on the equipment, and extend the service life of the equipment.

Intelligent dual output main road shutdown SOC: can be set to 30% (turn off non critical loads in advance). Priority is given to ensuring the continuous operation of key load equipment (such as refrigerators, lighting, monitoring, etc.), and non critical load equipment (such as air conditioners, etc.) is cut off earlier, reserving more power for the second output load.

Intelligent dual output main road recovery SOC: 85%-90%. Because charging depends entirely on PV, it is necessary to charge to a higher SOC before restoring the main road to avoid power waste caused by repeated switching.

2. Charging priority - SNU (PV and mains are charged at the same time, PV is consumed first)

In this mode, mains can be used as an emergency supplement (not long term dependence), PV is charged first, and mains automatically supplements when insufficient, with fast charging speed and high stability.

Core logic: Because there is mains "bottom line charging", there is no need to reserve excessive power, and the battery energy can be more fully utilized.

SOC setting suggestions:

Charging cut off SOC: can be set to 100%. With mains supplement, the full charge energy storage can be maximized to cope with power supply at night or on rainy days, and the high temperature in summer can be reduced to 95% to balance the battery life.

Shutdown SOC: can be set to 20%. To avoid excessive discharge of the battery, select this charging mode, which is without mains backup source supplement, and reserve power for key load equipment to avoid direct power outage.

Low voltage recovery SOC: can be set to 30%. Mains can assist charging, and it can be restarted when charged to 30%, reducing waiting time.

Inverter to mains SOC: If the SOC is in off grid mode because there is no mains access, the function of the SOC will not work, so keep the default value (10%). If the user can access the mains to supplement, the default value of 10% can also be maintained. In off grid mode, battery inverter is used first, and the mains is only used for emergency and supplementation. It is discharged to 10%, and the mains can be quickly replenished.

Mains to inverter SOC: If the SOC is in off grid mode because there is no mains access, the function of the SOC will not work, so keep the default value (80%). If the user can access the mains to supplement, it can be set to 70%. The mains replenishment is fast, and the battery can be switched back to 70% to reduce the consumption of the mains.

Intelligent dual output main road shutdown SOC: When there is sufficient light, it can be set to 25%. Because the photovoltaic and mains are charged at the same time, the charging is stable, and the main road output can be disconnected later, taking into account the user experience.

Intelligent dual output main circuit recovery SOC: can be set to 80%, fast charging, the main circuit can be restored after charging to 80%, without waiting for excessive power to start.

3. Charging priority - CSO (PV priority, mains power will intervene to supplement when PV is not available)

Although the CSO mode has "PV priority" and "mains power supplement", in off grid mode, mains power only plays a supplementary role. For example, the mains power in many foreign users' areas is unstable and even blackouts occur, so in fact the CSO mode is equivalent to OSO (PV charging only). However, this mode is suitable for some users to temporarily transition in scenarios with mains power. In addition, some users are in areas with sufficient sunlight, stable mains power but high electricity costs, and hope to make the most of PV, that is, use PV to charge during the day and use mains power to charge at night.

SOC setting suggestions:

Refer to OSO, but can be slightly relaxed (because users may assume that there is a mains backup, and it is necessary to avoid insufficient power supply caused by over conservativeness):

Shutdown SOC: can be set to 15%-20%, and can be set to 15% when there is mains power on cloudy days; when there is insufficient continuous sunlight due to weather factors, it can be set to 20%, taking into account both battery safety and power utilization.

Low voltage recovery SOC: can be set to 30%-35%, PV + mains hybrid charging, medium speed between SNU and OSO.

Charging cut off SOC: can be set to 100%, PV full charging during the day, and mains full charging on cloudy days to ensure sufficient battery energy storage.

Inverter to mains SOC: If the SOC is in off grid mode due to no mains access, the function of the SOC will not work, so keep the default value (10%). If the user can access the mains to supplement, it can be set to 12%-15%, PV is used first, and the mains is switched when there is no PV to avoid excessive discharge of the battery.

Mains to inverter SOC: If the SOC is in off grid mode due to no mains access, the function of the SOC will not work, so keep the default value (80%). If the user can access the mains to supplement, it can be set to 75%, between SNU charging mode (70%) and OSO charging mode (85%). The mains can be switched back when it reaches 75%, reducing dependence on the mains.

Intelligent dual output main road shutdown SOC: can be set to 25% when there is sufficient sunlight during the day, and can be set to 30% on cloudy days when there is mains power (flexible adjustment).

Intelligent dual output main road recovery SOC: can be set to 80%, charge to 85% and recover, balancing the battery charging speed and power reserve.

The above inverter SOC setting suggestions are for reference only. In off grid mode, users can better utilize PV and mains power, increase battery life, reduce electricity costs, and ensure stable and reliable power supply in off grid environments by correctly setting the inverter SOC. At the same time, users need to regularly check the battery status and inverter working conditions during operation, and make appropriate adjustments and optimizations to the SOC settings according to the actual use effect.

If you want to know more about Xindun hybrid inverter, please visit our official website (https://www.xinduninverter.com/) or contact Xindun's team.