Introduction #
The Custom control logic allows users to modify detailed parameters that directly influence how the inverter and battery operate. This provides flexibility but also requires a solid understanding of how the system works. Incorrect configuration may reduce profitability or cause unexpected behavior.
Prerequisites #
• Qilowatt account created → Creating a User Account
• Device connected to WiFi → Connecting a Device to WiFi
• Inverter added to the Qilowatt app → Module Setup
• Solar inverter configured → Solar Inverter Setup
• Control logic set to Custom → Control Logics
• Device connected to WiFi → Connecting a Device to WiFi
• Inverter added to the Qilowatt app → Module Setup
• Solar inverter configured → Solar Inverter Setup
• Control logic set to Custom → Control Logics
Step-by-step Guide #
1. Charging and discharging losses #
• Low-voltage batteries (<100 V): typically 14–20% loss per cycle.
• High-voltage batteries: typically 8–14% loss per cycle.
• Adjust values according to your battery’s voltage. The higher the voltage, the lower the current → less heat and lower losses.
• High-voltage batteries: typically 8–14% loss per cycle.
• Adjust values according to your battery’s voltage. The higher the voltage, the lower the current → less heat and lower losses.
2. Charging and discharging degradation cost #
• Every kWh charged into or discharged from the battery shortens its lifespan.
• Manufacturers usually guarantee a lifetime of ~6000 cycles. Based on battery cost, capacity, and expected cycles, you can calculate LCOS (Levelized Cost of Storage), which shows the cost per kWh of using the battery.
• LCOS should be split equally between charging and discharging degradation costs.
• Manufacturers usually guarantee a lifetime of ~6000 cycles. Based on battery cost, capacity, and expected cycles, you can calculate LCOS (Levelized Cost of Storage), which shows the cost per kWh of using the battery.
• LCOS should be split equally between charging and discharging degradation costs.
3. Minimum state of charge for selling (Sell Min SOC) #
• Defines how much energy must remain in the battery after a sell command finishes.
• Example: if Min SOC = 15% and Sell Min SOC = 20%, then 5% remains in the battery after selling.
• Each percent left unsold reduces profitability but may be useful in specific cases.
• Example: if Min SOC = 15% and Sell Min SOC = 20%, then 5% remains in the battery after selling.
• Each percent left unsold reduces profitability but may be useful in specific cases.
4. Minimum state of charge for PV Sell (PV Sell Min SOC) #
• Defines the minimum SOC required before PV Sell mode can activate.
• PV Sell starts in the morning when PV forecast ≥ historical average consumption.
• For fluctuating loads, it’s wise to store some energy in the battery before PV Sell to avoid covering consumption from the grid.
• PV Sell starts in the morning when PV forecast ≥ historical average consumption.
• For fluctuating loads, it’s wise to store some energy in the battery before PV Sell to avoid covering consumption from the grid.
⚠️ Recommended: 2–5% higher than Min SOC. If set too high, expensive morning energy will be stored in the battery, reducing profitability.
5. Enable PV Sell #
• Should be disabled if the inverter has no PV input or for specific models (e.g., Deye, Sungrow) where the export limit is more than 2× lower than the total PV capacity.
• If PV input and export work normally, keep this enabled.
• If PV input and export work normally, keep this enabled.
6. Planned battery state of charge (end of period) #
• The “end of period” = the last hour for which day-ahead market prices are available.
• This setting controls the target battery SOC at the end of that period.
• Recommendation: set around 60% SOC.
• This setting controls the target battery SOC at the end of that period.
• Recommendation: set around 60% SOC.
7. Buy price #
• Minimum extra revenue required for charging the battery.
• Not recommended — no practical use case has been identified.
• Not recommended — no practical use case has been identified.
8. Sell price #
• Minimum extra revenue required when discharging from the battery.
• Example: if set to 0.10 €, the system will only sell if it earns 10 cents per kWh in addition to covering losses and degradation costs.
• Example: if set to 0.10 €, the system will only sell if it earns 10 cents per kWh in addition to covering losses and degradation costs.
Result #
The Custom control logic enables detailed fine-tuning of inverter and battery behavior. With correct settings, the system can be adapted to very specific use cases. However, incorrect values may lead to lower profitability.
If it Doesn’t Work #
• If the system does not behave as expected, review all parameters carefully and compare with your battery manufacturer’s specifications.
• If the outcome is unsatisfactory, restore default logic → Maximum Profit or Self-consumption.
• If the outcome is unsatisfactory, restore default logic → Maximum Profit or Self-consumption.
⚠️ Qilowatt support does not provide assistance with Custom settings or troubleshooting. Responsibility for Custom configuration lies entirely with the user.
