APsystems DS3-L730VA single-phase microinverter for two PV modules

Overview

DS3-L is the 730VA model of the APsystems DS3 series: one unit takes two PV modules, each on its own MPP tracker, and feeds 3.2A into a 230V single-phase circuit. Inputs accept 18A operating and 22.5A short-circuit current, and APsystems recommends modules of about 255–550Wp. At 2.7kg it is the lightest DS3. The datasheet allows up to seven units on a 2.5mm² branch and eight on 4mm², or 14 and 16 modules, for residential and commercial roofs.

• DS3-L 730VA, DS3 880VA, DS3-H 960VA at 230V
• Two modules per unit, one MPPT each
• Up to 20A input current per channel
• 97.3% peak efficiency, 99.5% MPPT efficiency
• Encrypted ZigBee to ECU, EMA portal monitoring
• 12-year standard warranty, extendable to 25 years

How it works

Each DS3 unit mounts on the racking behind two PV modules and converts their DC output into 230V single-phase AC. Both inputs have their own MPP tracker working between 28 and 45V, so a shaded or differently oriented module does not pull down its neighbour. DC voltage at the module never exceeds the module's own open-circuit voltage, with a 60V input limit. Galvanically isolated high-frequency transformers, an integrated safety protection relay and Reactive Power Control complete the design.

Choosing between DS3-L, DS3 and DS3-H

The three models share housing, voltage ranges and 97.3% peak efficiency, and differ in output and input current. DS3-L delivers 730VA with 18A per input and suits modules of about 255–550Wp. DS3 delivers 880VA with 20A per input for 300–620Wp modules, and DS3-H 960VA for 330–660Wp modules. APsystems states the series is backwards compatible with QS1 and YC600 microinverters and their accessories, which helps when extending older systems.

Installation and compatibility

Units connect to the Y3 AC bus cable, closed with an end cap and Y-CONN caps on unused ports. The datasheet allows 7, 5 or 5 units (DS3-L, DS3, DS3-H) per 2.5mm² branch and 8, 7 or 6 per 4mm² branch, subject to local rules. Keep at least 2cm free above and below each unit, DC leads under 3m, and both conductors of a module on the same channel. Bipolar breakers are mandatory; RCDs only where local code requires them.

Grounding is possible through the PE wire of the bus cable, the grounding washer on a grounded rack or an external lug. The datasheet lists EN 50549-1/-10, CEI 0-21, VDE-AR-N 4105, UTE C15-712-1, UNE 217002, RD 1699, G98/G99 and G100 among its grid compliances, and APsystems publishes Italian, German, French, Polish and Spanish certificates for the series.

Monitoring and warranty

Microinverters report over encrypted ZigBee to an APsystems ECU gateway, which uploads module-level data to the EMA web portal and EMA Manager app; APsystems recommends no more than 80 inverters per ECU. A status LED blinks green ten times at start-up. The standard warranty is 12 years, extendable to 25 years, but it requires the system to stay connected to EMA through the ECU; otherwise only the 2-year legal warranty applies.

Questions and answers