Three Functions in One Unit

The IFIND SD400 combines three essential power-management functions in one compact enclosure:

Power Inverter

It converts DC power from the solar array or battery into AC power for compatible household appliances, office equipment, tools and selected motor loads.

MPPT Solar Controller

The built-in MPPT controller tracks the operating point of the PV array and adjusts solar input as sunlight and panel conditions change. This removes the need to configure a separate external MPPT controller for a standard installation.

Grid Charger

When utility power is available, the integrated charger can supply connected loads and charge a compatible battery bank according to the selected operating priority.

Combining these functions reduces the number of separate components required in the power system and simplifies wiring, installation and routine operation.

Battery-Free Daytime Operation

The inverter can operate without a connected battery when sufficient solar power is available during the day. PV energy is converted directly for compatible AC loads, allowing users to build a daytime solar system first and add energy storage later if required.

Battery-free operation does not provide stored energy. If solar input drops below the load requirement and no utility source is available, the output may be reduced or interrupted. Applications that require power at night, during poor weather or through a utility outage should include a properly sized battery bank or another approved backup source.

This configuration is suitable for projects that want to reduce the initial battery investment while retaining the option to expand the system later.

Flexible Energy Management

The hybrid solar inverter manages energy from the PV array, utility input and an optional battery bank. Source and charging priorities can be adjusted to match different site conditions.

Available operating logic includes:

• Solar-first operation for greater daytime PV use

• Utility support when solar production is insufficient

• Battery support when energy storage is installed

• Adjustable AC and PV charging settings

• Automatic restart after AC input recovers

• Configurable charging current and voltage

• Selectable power-source priority

The operating priority should be configured according to local grid conditions, daily load patterns and the required level of backup power.

MPPT and Pure Sine Wave Output

Wide MPPT Operating Range

The listed configurations provide an MPPT voltage range of 60–450VDC, with a nominal PV voltage of 360VDC and maximum PV input voltage of 500VDC. This range gives system designers flexibility when arranging compatible solar modules in series.

The complete PV string must remain within the inverter’s voltage, current and power limits under all expected temperatures. Solar module open-circuit voltage can rise in cold weather, so PV string sizing should be verified before installation.

Pure Sine Wave Power

Pure sine wave output is designed for a broad range of AC loads, including lighting, televisions, computers, refrigerators, fans and other compatible equipment.

Motor-driven loads such as pumps, compressors and air conditioners may draw substantially more current during startup than during normal operation. Their starting current, rated power and supply requirements must be checked before the inverter configuration is selected.

Conversion Performance

The published specification lists maximum DC-to-AC conversion efficiency of up to 98% in grid-tie operation and 94% efficiency in battery-mode DC-to-AC operation. Actual system performance depends on load level, PV conditions, wiring, temperature and operating mode.

Home and Pump Applications

Household Solar Power

For household systems, the inverter can supply appropriately sized combinations of:

• LED lighting

• Televisions and communication equipment

• Computers and office electronics

• Fans and small household appliances

• Refrigerators and freezers

• Selected power tools

The total continuous load and simultaneous starting demand must remain within the selected inverter’s output capacity.

Water Pump Systems

The inverter may also be considered for compatible pump applications where the motor voltage, phase, rated power and starting characteristics match the selected output.

Before confirming a pump system, provide:

• Pump motor rated power

• Rated voltage and phase

• Running and starting current

• Maximum operating frequency

• Required daily running time

• Water head and flow requirement

• Available PV array information

This product should not automatically be treated as a general-purpose solar pump VFD. Pump compatibility must be checked against the exact inverter configuration and motor nameplate.

Systems with Optional Storage

A battery bank can be added when nighttime operation, cloudy-weather support or backup power is required. The battery voltage, chemistry, capacity, charge current and communication protocol must match the inverter settings.

Battery and Charging Options

The inverter supports configurable charging for compatible lead-acid and lithium batteries.

Battery-related functions include:

• Adjustable charging current

• Adjustable charge voltage

• Lead-acid or lithium battery selection

• Lithium battery activation and wake-up support

• Cold-start function

• Intelligent three-stage AC charging

• BMS communication through the supported interface

Battery parameters should follow the battery manufacturer’s limits. Incorrect voltage, current or battery-type settings may reduce performance or damage connected equipment.

Protection and Communication

Built-In Protection

The inverter includes protection functions for common electrical and operating faults:

• Output overload

• Overtemperature

• Short circuit

• Low battery voltage

• Reverse battery connection

Protective functions reduce equipment risk but do not replace suitable breakers, fuses, surge protection, grounding or installation by qualified personnel.

Communication Options

Standard and optional interfaces include:

• RS232

• RS485

• BMS communication

• Dry contact

• Optional Wi-Fi

• Optional GPRS monitoring

Available interfaces may vary by configuration. Confirm the required monitoring accessory, BMS protocol and remote communication method before ordering.

Installation Environment

The enclosure is rated IP20 and is intended for installation in a dry, protected and ventilated indoor location. It should not be exposed directly to rain, dust accumulation, condensation or strong heat sources.

Technical Specifications

Power and PV Input

AC and Output Data

Physical and Environmental Data

Specifications may vary by configuration or firmware version. Final electrical data should be checked against the model label, datasheet and order confirmation.

Manufacturing and Technical Support

IFIND is an inverter manufacturer established in 2016 in Haiyan, Zhejiang. The company states that its facility covers approximately 15,000 square metres and employs more than 150 people, including a product engineering team.

Its manufacturing and service capabilities include:

• In-house SMT production

• Product engineering and application support

• OEM and application-specific configuration

• Remote technical assistance

• Pre-shipment technical coordination

• Service support through overseas agents

For reliable project matching, IFIND engineers can review the load list, PV array, utility input, battery specification and communication requirements before the order is confirmed.

Before Selecting Your Inverter

Prepare the following information for technical review:

1. Required continuous output power

2. Highest simultaneous load

3. Starting power of motors and compressors

4. AC output voltage and phase

5. Utility input voltage and frequency

6. Solar panel model and quantity

7. PV string open-circuit and operating voltage

8. Battery chemistry, voltage and capacity, if used

9. Required communication interface

10. Indoor installation temperature and ventilation

11. Need for nighttime or outage operation

12. Pump motor nameplate, when applicable

Providing this information helps determine whether the 3.6kW, 4.2kW or 6.2kW configuration is appropriate.

Hybrid Solar Inverter FAQs

What happens if sunlight suddenly drops during battery-free operation?

The result depends on the selected priority mode and whether utility power is available. The inverter may draw support from the grid, reduce the available output or stop supplying the load. A battery is recommended when short power interruptions are unacceptable.

Can I install the inverter now and add batteries later?

Yes, the system can initially be configured for battery-free daytime operation and later connected to a compatible battery bank. Battery voltage, chemistry, charging limits and communication requirements must be checked before expansion.

How should I calculate the PV string voltage?

Add the operating voltage of the modules connected in series to calculate the approximate working voltage. Also calculate the cold-weather open-circuit voltage. The complete string must remain within the specified MPPT range and below the maximum PV input voltage.

Can the inverter be mounted outdoors?

The listed enclosure rating is IP20, so it should be installed indoors or inside a suitable weather-protected electrical cabinet. Adequate clearance and ventilation are required to control operating temperature.

Does pure sine wave output mean that any pump can be connected?

No. Pure sine wave output improves compatibility, but the pump’s voltage, phase, running power and startup current must still match the inverter. Some pumps require a dedicated solar pump VFD or additional motor-control equipment.

Can multiple inverter units operate in parallel?

Parallel operation depends on the exact power version, hardware and firmware. Do not assume every SD400 configuration supports it. The parallel model, maximum unit quantity and required accessories should be confirmed before ordering.

What routine maintenance does the inverter require?

Keep the ventilation openings clean, check wiring and terminals periodically, watch for abnormal temperature or noise, and review fault records when available. Maintenance should be performed with the system isolated and according to the installation manual.

Does the inverter provide power at night without a battery?

Only if another approved source, such as the utility grid, is available and the system is configured to use it. Solar panels alone cannot provide nighttime power, so a battery is required for stored off-grid energy.