Smart Meter - Single Phase
A smart meter for the photovoltaic system measures, at the property connection point, how much electricity is currently being drawn and how much is being fed into the grid. The inverter needs this value to charge the storage unit at the right time, to limit the grid feed-in to a specified value and to supply consumers such as a wallbox with surplus electricity. The range includes meters from Fronius, Growatt, SAJ and SunGrow.
Not to be confused with the meter provided by the metering point operator
In everyday language, the term ‘smart meter’ often refers to the intelligent metering system installed and billed by the metering point operator. These meters do not replace that billing meter. They are installed additionally in the meter cupboard or in the sub-distribution board, usually on a DIN rail, and transmit their meter readings via RS485 to inverters or storage systems.
Which meter is compatible with which inverter
Communication depends on the manufacturer. The meter is therefore selected to match the brand and model series of the inverter.
| Meters | Phases | Current | Compatible with |
|---|---|---|---|
| Fronius Smart Meter TS 65A-3 | three-phase | up to 65 A | Fronius inverter |
| Growatt SPM-C | single-phase | 5 to 60 A | Growatt inverter |
| Growatt TPM-E (SDM630 v3) | three-phase | Direct measurement up to 80 A | Growatt SPH, MIN XH, MOD |
| Growatt DTSU 666 (3PH) | three-phase | – | Growatt inverter |
| SAJ DTSU 666 100A | three-phase | up to 100 A | SAJ inverter |
| SunGrow DTSD1352-C/1 | three-phase | 6 A, via current transformer | SunGrow CX Series (SG33-125CX) |
In Germany, three-phase domestic connections are standard; a single-phase meter such as the Growatt SPM-C is suitable for single-phase inverters. According to the manufacturer, the current transformers are not included in the scope of delivery for the SunGrow DTSD1352. According to the manufacturer, the Growatt TPM-E measures each phase individually in both directions, enabling a hybrid inverter to distribute the stored electricity with phase-accurate distribution.
Installation and operation
A smart meter is wired into the meter cupboard or the sub-distribution board. This should be carried out by a qualified electrician; ACTEC supplies the meter but does not install it. The protection ratings range from IP20 (SunGrow) via IP51 (Growatt) to IP54 (SAJ), whilst the operating temperature for the SAJ meter is −40 to +60 °C. The manufacturers provide a two-year warranty.
The compatible devices can be found amongst the hybrid inverters and in the inverter range, whilst monitoring accessories such as dongles are available in the inverter accessories section. Anyone wishing to charge their car with surplus energy will also need a wallbox with solar integration.
Frequently asked questions about smart meters for PV systems
Do I need a smart meter for my PV system?
Yes, if you have a storage system, a grid feed-in limit or wish to charge your car with surplus energy. Without a meter, the inverter cannot determine the consumption within the home.
Is every smart meter compatible with every inverter?
No. Communication depends on the manufacturer. Choose the meter specified by your inverter manufacturer for that model series.
Does the smart meter replace my electricity meter?
No. The metering operator’s billing meter remains in place. The solar panel system’s smart meter takes additional readings and sends the data to the inverter and storage system.