Hoymiles HMS-400-1T400VA single-phase microinverter for one PV module

Overview

The HMS-400-1T is a one-input Hoymiles microinverter with 400VA output for a single PV module, typically 320W to 540W and more according to Hoymiles. Its MPPT tracks from 16V to 60V with up to 14A input current and 25A short-circuit current, and the input accepts up to 65V. At 1.75kg and 182×164×30mm it mounts under the module on the racking. Up to 14 units can share one 2.5mm² AC line at 230V, and Hoymiles presents the one-module design as flexible for varied layouts.

• One MPPT per module input, 16–60V
• Output from 300VA (1T) to 2000VA (4T)
• Sub-1G wireless link to the Hoymiles DTU
• Isolated HF transformer, rapid shutdown compliance
• IP67, -40…+65°C, no fans
• EN 50549-1, VDE-AR-N 4105 and VFR 2019 compliant

How it works

HMS microinverters convert the DC of each PV module into 230V single-phase AC directly at the module. The 1T models take one module, the 2T models two and the 4T models four, and every input has its own maximum power point tracker working from 16V to 60V. A shaded, soiled or differently oriented module therefore only affects its own output. DC voltage stays at module level, and a galvanically isolated high-frequency transformer separates the PV side from the grid.

Production data travels wirelessly over Sub-1G radio to a Hoymiles DTU gateway, which forwards it to the S-Miles Cloud platform for module-level monitoring and remote management. Hoymiles chose Sub-1G for its stable communication under varied site conditions. Reactive power control is built in, and the European models are certified to EN 50549-1:2019, VDE-AR-N 4105:2018 and VFR 2019.

Key features

Across the range, start-up voltage is 22V, nominal MPPT efficiency 99.8%, night consumption below 50mW and total harmonic distortion below 3%. Power factor is adjustable from 0.8 leading to 0.8 lagging. The housings are naturally cooled with no fans, rated IP67 and specified from -40°C to +65°C. Typical module power recommended by Hoymiles ranges from 240W for the smallest models to 670W and more for the 500VA-per-input versions.

Installation and compatibility

The microinverter is fixed to the racking under the module with a 9Nm screw, keeping at least 2cm of free space around the enclosure and avoiding metal obstacles that could disturb the radio link. Depending on the version, AC connections use Hoymiles' single-phase trunk cable or the Flex-S3 cable system, with trunk connectors, connection cables, an end terminal and sealing caps, or a field connector for a single unit. Hoymiles' online compatibility calculator should be used to confirm that module voltage and current suit the selected model.

The number of units per AC line depends on cable cross-section and model. With 2.5mm² cable at 230V the user manuals allow, for example, 11 HMS-500-1T, 5 HMS-1000-2T or 2 HMS-2000-4T per line, and more with 4mm² or 6mm² cable. Local rules on branch circuits and protection always take precedence.

Monitoring and warranty

Commissioning is done with the S-Miles Installer app: it creates the plant in S-Miles Cloud and links the DTU and microinverters, after which production and faults of every module are reported online. Hoymiles' European warranty terms give non-Wi-Fi HMS microinverters a 12-year standard warranty, extendable to 25 years if the extension is requested within 36 months of purchase.

Questions and answers