Solar-Log monitoring provides extensive energy and system data. Terms like yield, self-consumption or autonomy seem clear at first, but often lead to misunderstandings in practice. This article explains the most important metrics in Solar-Log and puts them into context.
For a general overview, see Solar-Log Monitoring: Features, Login & Data Overview.
What data does Solar-Log display?
Depending on system configuration and installed measurement hardware, the following values may be shown:
- PV yield
- real-time power
- electricity consumption
- self-consumption rate
- grid import
- feed-in
- storage values
- system status
Not every system automatically displays all values. Scope and accuracy depend on inverters, meters and additional hardware.
Yield in Solar-Log
Yield describes the energy generated by the photovoltaic system. It is measured in kilowatt-hours and typically displayed as:
- daily yield
- monthly yield
- yearly yield
- total yield
Yield only indicates how much electricity was produced, not how it is used.
Power vs Yield: important difference
A common misunderstanding is confusing power with yield.
- Power (kW) is the current electricity production
- Yield (kWh) is the amount of energy generated over time
Fluctuating power values are normal and depend on weather, time of day and consumption.
Understanding consumption and self-consumption
Consumption describes the total electricity demand of a household or business.
Self-consumption is the share of generated solar energy that is used directly or later supplied from storage.
High yield does not automatically mean high self-consumption, since part of the energy may be fed into the grid.
Grid import and feed-in
Grid import
Grid import is the electricity drawn from the public grid when the PV system does not produce enough energy.
Feed-in
Feed-in is the portion of solar energy that is not used on-site and is exported to the grid.
Simplified formula:
PV yield = self-consumption + feed-in
Small deviations due to measurement differences are possible.
Storage values in Solar-Log monitoring
If a battery storage system is integrated, additional data is available:
- battery state of charge
- charging power
- discharging power
The battery increases self-consumption by storing excess energy.
Why do values fluctuate during the day?
Fluctuations are technically normal and caused by:
- changing solar irradiation
- varying electricity demand
- system energy management
- charging and discharging processes
Individual values should not be evaluated in isolation.
Autonomy and self-consumption rate
Solar-Log often displays metrics such as:
- autonomy level
- self-consumption rate
These are useful for long-term analysis but should not be interpreted based on a single day.
Data delay in Solar-Log
Displayed data is often updated with a delay.
This means:
- no guaranteed real-time data
- updates typically occur every few minutes
- daily values are only complete at the end of the day
For reliable analysis, completed time periods should be used.
Common misunderstandings about Solar-Log data
- high yield does not mean high autonomy
- low feed-in is not an error
- differences between views are normal
- short-term fluctuations are system-related
Data should always be interpreted in context.
When is the data sufficient and when not?
Sufficient for:
- single systems
- standard monitoring
- overview of energy flows
- optimizing self-consumption
Limited for:
- complex billing scenarios
- missing measurement hardware
- highly detailed real-time analysis
Frequently asked questions about Solar-Log data (FAQ)
Why do yield and consumption not match?
Yield describes generated energy, while consumption describes used electricity. Some energy is fed into the grid or stored.
Why does my electricity meter show different values?
External meters are authoritative. Solar-Log uses internal measurements that may differ.
Why don’t I see consumption data?
Without appropriate measurement hardware, consumption cannot be recorded correctly.
Is the data real-time?
No. Data is updated with a delay and is intended for analysis.
What is the difference between power and yield in Solar-Log?
Power and yield are two different values in Solar-Log. Power, measured in kilowatts, describes the current output of the PV system at a specific moment. Yield, measured in kilowatt-hours, describes the amount of energy generated over a period of time. This is why the current power value can fluctuate strongly during the day, while the yield value increases over time.
