Morningstar SureSine Pure Sine Wave Inverter SI-300-115V-UL 300Watts

Price: $237.99 Quantity: Product #: IMSC424 Mfg #: SI-300-115V-UL
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Morningstar SureSine Pure Sine Wave Inverter SI-300-115V-UL, 300 Watts 115VAC 60Hz UL Listed Off-Grid Inverter.

The SureSine inverter has been developed using Morningstar’s power electronics expertise and 25 years of experience with remote off-grid photovoltaic (PV) systems. The SureSine™ is a 300 watt pure sine wave inverter (12 volt DC input) designed specifically for remote off-grid photovoltaic (PV) systems. It is an ideal inverter for rural electrification projects, telecom, remote cabins and weekend homes, and RV or caravans and boats. The SureSine’s combination of performance, features and competitive price provides the best small inverter value on the market.

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. A sine wave will extend the life of the household appliances (lights, TV, fans) and improve load performance.

Toroidal transformer design – Generates good wave form throughout the range of input voltages.

Outstanding Surge Capability – Handles a 200% surge during load start-up, to a maximum of 600 watts.

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 450mA while powering loads. During no load conditions, solar energy is not wasted because the SureSine automatically powers down to stand-by 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 environments.

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 & Programmability – Four DIP switches provide easy adjustability of several system parameters. Additional adjustability is possible via RJ-11 to RS-232 adapter to a personal computer and using Morningstar’s PC software.

Electrical Specifications

  • Continuous Power Rating: 300 Watts @ 25°C
  • Peak Power Rating (10 minutes): 600 Watts @ 25°C
  • DC Input Voltage: 10.0V – 15.5V
  • Waveform: Pure sine wave
  • AC Output Voltage (RMS): 115V +/– 10%
  • AC Output Frequency: 60 Hz +/– 0.1%
  • Peak Efficiency: 92%
  • Total Harmonic Distortion (THD): < 4%
  • Self Consumption
    • Inverter On (no load): 450mA
    • Inverter Off: 25mA
    • Stand-by: 55mA
  • Low Voltage Disconnect (LVD): 11.5 V or 10.5 V
  • Low Voltage Reconnect: 12.6 V or 11.6 V
  • LVD Warning Threshold (buzzer): 11.8 V or 10.8 V
  • LVD Delay Period: 4 minutes
  • High Voltage Disconnect: 15.5 V
  • High Voltage Reconnect: 14.5 V
  • Standby On Threshold: ~ 8 Watts
  • Standby Off Threshold: ~ 8 Watts
  • High Temperature Disconnect: 95°C (heatsink)
  • High Temperature Reconnect: 80°C (heatsink)
  • Two separate versions available: 220VA C at 50 Hz or 115VA C at 60 Hz

Electronic Protections

  • Reverse Polarity (fused)
  • AC Short Circuit
  • AC Overload
  • High Voltage Disconnect
  • Low Battery Disconnect
  • High Temperature Disconnect

Mechanical Specifications

  • Dimensions:  213 x 152 x 105 mm/8.4 x 6.0 x 4.1 in
  • Weight 4.5 Kg / 10.0 lbs
  • AC Terminals:  Max. Wire Size 4 mm2 / 12 AWG
  • DC Terminals:  Max. Wire Size 2.5 to 35 mm2/14 to 2 AWG
  • Remote On/Off Terminals:  Max. Wire Size 0.25 to 1.0 mm2/24 to 16 AWG
  • Enclosure           IP20/Cast anodized aluminum

Environmental Specifications

  • Ambient Operating Temp –40°C to +45°C
  • Storage Temperature –55°C to +85°C
  • Humidity 100% (non-condensing)
  • Tropicalization:   Conformal coating on printed circuit boards/Epoxy encapsulated transformer and inductors


  • CE Compliant
  • UL Listed (UL 458) –
  • cUL (CSA C22.2 No. 107.1-01) –

Warranty:  2 year warranty period


The attached photo is of a Tucker "Sno-Cat" panel which was modified to support computers and communications. This vehicle recently completed the GRIT (Greenland Inland Traverse), covering over 1,400 miles on the Greenland ice cap. There is 170 watts of PV mounted to the roof of the Tucker which runs through a Morningstar charge controller to the vehicles heavy duty batteries. Many of the loads were run off of straight DC to prevent any conversion losses. The Morningstar inverter took care of the small AC loads (computers, etc.). Since this vehicle towed the living module for the crew, more batteries were mounted along with the Morningstar inverter in the coach, so they could also have AC/DC power. Those batteries were in parallel to the vehicle batteries so all shared the loads and charging inputs. This system bounced across the ice cap for a couple of months, getting cold soaked every night and heated up every day. Never a problem developed, and the crew loved the system. Photo Courtesy of Polar Field Services.

SureSine Example Application A

Solar home systems in Venezuela, 150 installed.

SureSine Example Application B

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