• 115V Version

  • 220V Version


The SureSine™ is a pure sine wave inverter delivering AC power in off-grid solar applications, including rural electrification, telecom, remote homes, RVs, caravans and boats. A cast, anodized aluminum enclosure with no internal cooling fan needed ensures long-term reliability in the harshest conditions. The SureSine’s combination of performance, features and competitive price provides the best small inverter value on the market. It is highly reliable, having no internal cooling fan or other moving parts prone to failure.

Key features and benefits

  • Improved Load Operation
    • Pure Sine Wave – provides quality AC equivalent to grid power.
    Toroidal transformer design generates good wave form throughout the range of input voltages. 600W peak/surge power.
    • Outstanding Surge Capability – handles a 200% surge during
    load start-up, to a maximum of 600W.
  • More Power Available
    • High Efficiency – a high peak efficiency will reduce heating and
    make more solar energy available for powering loads.
    • Low Self-Consumption – The SureSine consumes only 450mA of
    current during operation with a full sine-wave present at the AC
    output. During periods where no load is detected, solar energy
    is not wasted because the SureSine automatically powers down
    to standby mode, reducing self-consumption to one-tenth of
    operating consumption.
  • Extremely High Reliability
    • Extensive Electronic Protections – the SureSine has
    extensive electronic protections that will automatically protect
    against faults and user mistakes such as short circuit, overload,
    high temperature and low voltage disconnect. Recovery from
    most faults is automatic.
    • No Internal Cooling Fan – a key design objective since fans often
    fail in harsh environments and are noisy, consume power and
    blow dirt into the electronics.
    • Tropicalization – the SureSine uses epoxy encapsulation,
    conformal coating, stainless steel hardware, and an anodized
    aluminum enclosure to protect against harsh tropical and marine
  • Other Features
    • More Information – the two LEDs provide important information
    to the user about system status and any fault conditions. An
    optional digital meter may be connected to the SureSine to
    display additional system information.
    • Remote On/Off – improves safety by making it easy to install
    the SureSine in an inaccessible location or enclosure. Reduces
    system cost by avoiding the need to add an AC safety disconnect
    to the system.
    • Adjustability & Communications – four DIP switches provide
    easy adjustability of several system parameters. Additional
    adjustability is possible using Morningstar’s USB MeterBus
    Adapter (UMC-1) to connect to a PC. Free 3rd-party MODBUS
    software is available for custom programming. IP-based
    communication, including SNMP, is enabled through
    Morningstar’s Ethernet MeterBus Converter (EMC-1).

Specifications and Certifications

Model SI-300-115V-UL (60 Hz) SI-300-220V (50 Hz)
Continuous Power Rating 300 Watts @ 25C 300 Watts @ 25C
Pek Power Rating (15 min.) 600 Watts @ 25C 600 Watts @ 25C
DC Input Voltage 10.0V - 15.5V 10.0V - 15.5V
Waveform Pure sine wave Pure sine wave
AC Output Votage (RMS) 220V or 115V +/– 10% 220V or 115V +/– 10%
AC Output Frequency 50 or 60 Hz +/– 0.1% 50 or 60 Hz +/– 0.1%
Nominal Battery Voltage 12V 12V
Peak efficiency 92% 92%
Total Harmonic Distortion (THD) <4% <4%
Self Consumption (Inverter ON - no load) 450mA 450mA
Self Consumption (Inverter OFF) 25mA 25mA
Self Consumption (Standby) 55mA 55mA
Operating Temperature Range -40 C to +45C -40 C to +45C
Warranty 2 Years 2 Years
CE and RoHS compliant Yes Yes
ETL Listed [UL-458] Yes
FCC Class B Part 15 Compliant Yes Yes
Manufactured in a Certified ISO 9001 Facility Yes Yes


  • EIA-485/RS-232 Communications Adapter [RSC-1]

    converts RS-232 to EIA-485 so up to 128 MS products can communicate on the same bus

  • Ethernet MeterBus Converter

    enables IP-based networking and internet connectivity for select Morningstar products

  • PC MeterBus Adapter

    converts a controller's RJ-11 meter port to a RS-232 serial connector for connection to a PC

  • Relay Driver

    programs conditional generator start/stop, high/low voltage alarms, load control and more

  • Remote Meter

    provides voltage, current and temperature readings up to 10 meters away from system

  • MeterHub

    enables up to 15 Morningstar products on a single MeterBus network

  • USB MeterBus Adapter

    converts RJ-11 interface to USB 2.0 interface to allow MS product to communicate with a PC