This is a multi-functional off grid photovoltaic inverter, integrated with MPPT photovoltaic charging controller, high-frequency pure sine wave inverter and UPS functional module, which is very suitable for off grid backup power supply and self use system. The design of high-frequency transformer enables the machine to provide reliable power conversion in a small size. This inverter can also operate in battery free mode.

The WiFi/GPRS module is a plug and play monitoring device installed on the inverter. With this device, users can monitor the operation status of the photovoltaic system anytime, anywhere through mobile phones or websites.


*MPPT ranges 120V~430V, 450Voc
*High frequency inverter with small size and light weight
*Pure sine wave AC output
*Solar and utility grid can power loads at the same time
*With CAN/RS485 for BMS communication
*With the ability to work without battery
*Parallel operation up to 6 unit (only with battery connected)
*WIFI/ GPRS remote monitoring (optional)

1. LCD displayLCD display2. Status indicator 3. Charging indicator 4. Fault indicator 5. Function keys 6. AC input

7. WiFi/GPRS communication interface 8. USB communication interface 9. CAN communication interface 10. RS485 communication interface 11. Dry node

12. PV input 13. Switch 14. Battery input 15. Parallel communication line interface 16. Parallel current sharing line interface 17. AC output 18. Circuit breaker

This is a multifunctional 230V off grid solar inverter, integrated with a MPPT solar charge controller, a high frequency pure sine wave inverter and a UPS function module in one machine, which is perfect for off grid backup power and self-consumption applications. This Hybrid inverter can work with 48V battery or without batteries.

Can be accessed to a variety of household appliances and office loads, power tools, industrial equipment, and electronic audio and video equipment, including refrigerators, lamps, televisions, fans, air conditioning and other AC loads

Important Note:

1. This is a wide voltage Hybrid inverter, The voltage that starts to connect to the solar panel must be above 150V for the Hybrid inverter to work normally. Means you can connect solar panels in series, saving you the cost of buying wires

The whole system also need other devices to achieve complete running such as PV modules, generator, or utility grid.

  1. Rated power 3.5KW, power factor 1 MPPT ranges 120V~430V, 450Voc
  2. High frequency inverter with small size and light weight Pure sine wave AC output
  3. Battery charging mode and load working mode can be set
  4. Adjustable inverter charging and output time
  5. Solar and utility grid can power loads at the same time With CAN/RS485 for BMS communication
  6. With the ability to work without battery
  7. Parallel operation up to 6 unit (only with battery connected)
  8. The WiFi / GPRS module is a plug-and-play monitoring device to be installed on the inverter. With this device, users can monitor the status of the PV system from the mobile phone or from the website anytime anywhere.(optional, Additional purchase required )



Parallel operation up to 6 unit (only with battery connected)

This inverter can be used in parallel with two different operation modes.

1. Parallel operation in single phase with up to 6 units.

2. Maximum 6 units work together to support 3-phase equipment. Four units support one phase maximum.


All inverters must be connected to the same batteries and ensure each group of cables from the inverters to the batteries in the same length.

Important Note:

The ground and neutral conductors of the SPF 3500 ES are not connected together and the enclosure does not become part of the ground return.

Test Methods: Use the multimeter’s beep gear to measure whether the neutral wire and the ground wire are connected together, if they are connected together, it will make a “beep” sound. If there is no sound, there is no connection.

Battery Charging Mode And Load Working Mode Can Be Set


Utility Charging Mode

  • Charging Algorithm: 3-Step
  • Max. AC Charging Current: 60Amp
  • Safety Certification: CE
  • Operating Temperature Range: 0℃ to 55℃
  • Storage temperature:-15℃~ 60℃
  • Dimension(D*W*H) : 485 x 330 x 135 mm
  • Net Weight: 11.5kg


Wiring Instruction

solar inverter

Wiring Instruction(When Your System Is Split Phase Systems ( 120V L+ 120V L+ N+G) ,Please Take This As Reference)

  1. Connect Ground wire to Ground terminal (Be sure to connect PE protective conductor first).
  2. Connect AC input L1 to Input L (Hot) terminal.
  3. Connect AC input L2 to Input Neutral terminal.
  4. Connect Output L (Hot) to AC output L1.
  5. Connect Output Neutral to AC output L2.

Important Note:

  • This single-phase 220V solar inverter is an international version Which can be used in 220Vac single phase systems and as well as in 120V/240V split phase systems.
  • This inverter charge can be connected to a separate 240V to 120/240 Volt split phase transformer(doesn’t included) to get two separate 120V hot lines for 120V loads.
  • This inverter only outputs 220Vac. It does NOT output 120Vac.


Company Profile

Growatt was founded in 2010 and is a worldwide leader of smart energy solutions.

Growatt Inverter is a new energy enterprise dedicated to the R&D and manufacturing of PV inverters including on-grid, off-grid and storage inverters, and user side smart energy management solutions as well. The power capacity of Growatt on-grid inverters ranges from 1kW to 100 kW, meanwhile its off-grid and storage inverters cover a power range from 1 kW to 630 kW. Growatt inverters are extensively used worldwide for applications in residential, commercial, utility-scale scenarios as well as other storage power station projects.


Since its foundation in 2010, Growatt Inverter  has established branch offices one after another in Germany, US, UK, Australia,
Thailand,India, Netherlands, etc in order to better serve the customers across the globe. Growatt always sticks to the R&D
investment and technology innovation, and provides customers with premium products and services through its core invertertec hnology, rigorous quality control and continuous improvement of customer service. By end of September 2018, Growatt has shipped over 1.2 million inverters to over 100 countries and regions across the globe, growing into a Global Top 10 Inverter Brand and becoming the No.1 Chinese Residential PV Inverter Brand.

The application case

Product Packagin


No Utility Grid Connection

Cause Analysis:If the AC side is disconnected, the inverter will not be able to detect the voltage of the mains.

Method of exclusion:Remove the output port of the inverter, and use the AC voltage range of a multimeter to measure whether the voltage (phase voltage) between the live wire and the neutral wire on the user side of the output port is 220V. If there is no AC 220V, it is judged that there is no problem on the inverter side If the external AC side is open circuit, it is necessary to check whether the safety switches such as air switch, knife switch, overvoltage and undervoltage protector are damaged or open circuit.

PV System Power Generation Is Low

Cause Analysis:The power generation problem is related to many factors, weather, temperature, shading, inverter, component orientation, component inclination, etc.

Check method:Weather: haze, rainy days, cloudy days, and bad weather will make the power generation of the system low.

In terms of temperature: photovoltaic panels have the best working temperature, so too high or too low temperature will lead to low conversion efficiency of the panels, resulting in low power generation of the photovoltaic system.

Occlusion: Check the surrounding environment for obstructions, including nearby trees, utility poles, storage tanks of solar water heaters, drying clothes, bird droppings on battery panels, front row of photovoltaic panels covering the back row, etc. The MPPT tracking of the inverter is like the barrel effect, so it is greatly affected by occlusion. If a block is occluded, the conversion efficiency of the entire string will be reduced, thereby affecting the power generation of the system.

Component orientation: Components with different orientations cannot be connected to the same MPPT, which will affect the tracking of the core inverter in the photovoltaic system, thereby affecting the power generation of the system.

Module inclination: Note that the installation inclination of the module should be the best angle for the local irradiation; different inclinations have different conversion efficiencies of photovoltaic panels at the same time, so when the solar irradiance is the strongest (generally 11 noon at noon) : 00 to 2:00 pm), the inclination angle of the appropriate module receives the most solar energy; different inclination angle power generation systems will produce different peaks, and by comparison, it can be found that the optimal inclination angle of the system is not the optimal inclination angle. Power generation is low.

Photovoltaic panel reasons: PV panels of different brands cannot be connected to the same string and MPPT. Note that damaged photovoltaic panels will affect the power generation of the entire string. If you encounter damaged strings, please replace them in time.

Inverter reason: The inverter does not generate electricity when it reports a fault, which will affect the power generation. The DC open circuit voltage should be set in the appropriate range of the inverter, and the board is not properly matched. For example, the open circuit voltage of the board is not the MPPT voltage of the inverter. Within the range, it will affect the power generation efficiency of the inverter, thereby affecting the power generation of the photovoltaic system.

Power grid reasons: power grid fluctuations occur from time to time, ensuring the quality of the power grid is an important condition to ensure the normal power generation of the inverter, so pay attention to grid voltage fluctuations, frequency fluctuations, etc., which will affect the power generation of the inverter, and even cause the inverter to report a fault. Nearby high-power capacitive inductive loads will also affect the quality of the power grid, thereby affecting the power generation of the inverter.

The Grid Voltage Is Too High

Cause analysis: The mains voltage exceeds the voltage range of the inverter’s normal grid-connected operation. If the grid voltage is too high, it will exceed the inverter’s factory-set grid-connected voltage upper limit (the factory-set voltage range is 195Vac~253Vac); it generally occurs in household distribution. If the photovoltaic power generation users cannot digest the surplus electricity locally, the line impedance is too large during the online process, causing the voltage on the output side of the inverter to be too high, causing the inverter protection to be disconnected from the grid or run at reduced load. It is also possible that the voltage fluctuation range of the rural grid itself is relatively large, and it is easy to exceed the upper limit of the inverter voltage, resulting in load reduction or off-grid.

Method of exclusion:Increase the output cable, the thicker the cable, the lower the impedance; the inverter is installed as close as possible to the grid connection point, the shorter the cable, the lower the impedance; change the resistivity of the cable, the resistivity of copper wire is much smaller than that of aluminum wire, generally Use copper wire; if the voltage of the rural grid itself exceeds the grid-connected voltage range of the inverter, the upper limit of the grid-connected voltage of the inverter can be adjusted appropriately.

Insulation Resistance Is Too Low

Cause Analysis:The inverter has the function of detecting the insulation resistance of the DC side. When the insulation resistance of the DC side is detected to be lower than 50kΩ, the inverter will report “PV insulation resistance is too low fault”. The DC components are leaking, and the DC side of the inverter is short-circuited to ground.

Troubleshooting:Disconnect the AC circuit breaker and the DC circuit breaker; use the special MC4 dismantling wrench to remove the positive and negative poles of the DC measurement string; ensure that the component bracket is reliably grounded; Read the measured positive-to-ground impedance reading of each channel, then connect the red test lead to the negative pole of the string, and then read the negative-to-ground impedance reading of each channel. If it is greater than 50kΩ, the inverter judges that the insulation of the string is reliable, less than or equal to 50kΩ, the inverter judges that there is a problem with the insulation of the string, the inverter will automatically protect and stop working and report “PV insulation resistance is too low”.

PV Voltage Too High

Cause Analysis:Different inverters have different DC voltage input ranges, so the number of solar panels in the string should be configured according to the DC voltage input range of the inverter, and the report “PV voltage high voltage” is generally due to the solar panels of the string. The number is too large, which is caused by exceeding the DC voltage range of the inverter.

Troubleshooting:Check the parameters of the inverter, the input range of the DC voltage, and then measure the open-circuit voltage of the string (the open-circuit voltage refers to the voltage of the string when the inverter is not connected to the grid).

PV Voltage Too Low

PV voltage refers to the open circuit voltage of the string, that is, the positive and negative voltages measured after the solar panels are connected in series. On the contrary, the terminal is loose and the contact is poor, and the string is disconnected.

Troubleshooting:To measure the PV voltage of the string, the DC voltage level of the multimeter is required. The red test lead is connected to the positive electrode, and the black test lead is connected to the negative electrode. Read the displayed reading of the multimeter. If the reading is within the rated input range of the inverter and is a positive number, the PV voltage is normal. .

Mobile APP Monitoring Lost Contact

Cause Analysis:There is no communication between the collector and the inverter; the collector is not powered on: the APP scans the serial number of the inverter; the installation position signal problem; the internal reason of the collector;

Troubleshooting:Check whether the 232 interface DIP switch is turned on; check whether the 232 interface is in contact with the collector; check whether the data communication of the inverter 232 interface is normal;

Scan the serial number of the collector, or manually enter the serial number and check code of the collector; check whether the installation location is blocked by the signal, or the WiFi collector cannot receive the router signal, and the GPRS is installed in the local without the network signal of the internal traffic card operator (Telecom traffic card cannot be used); observe the flashing light of the collector. If the external conditions are no problem, the collector does not have any connection response, which can be considered as an internal fault of the collector.

DC Draw Arc

Cause Analysis:Arc pulling occurs because the strings form a loop and there is current output, so arcing occurs. The possible reason is that the inverter is working and the strings are directly inserted and removed, or the positive and negative poles between the strings are short-circuited, and the positive and negative poles are reversed. The number of strings connected in series is unbalanced, etc.

Troubleshooting:Before plugging and unplugging strings, check that the inverter has been normally closed before plugging and unplugging. The inverter has current input in the working state, and the operation of plugging and unplugging strings will cause arcing phenomenon; check whether there is a positive or negative short circuit in the strings. Check whether the positive and negative of the strings are reversed, and then connect them to the inverter. When the strings with opposite polarities are connected to the same mppt, it is equivalent to connecting two strings to form a short-circuit arc; The number of solar panels connected in series is inconsistent, and in the same mppt, there will be perfusion between the strings, and arcs will be formed when the strings are inserted and removed.


9 reviews for GROWATT SPF 3500 ES OFF GRID, 3.5KW, 48V, BIG PV INPUT

    GROWATT SPF 3500 ES OFF GRID, 3.5KW, 48V, BIG PV INPUT photo review
    Marc Smith
    November 2, 2022
    Very good product. This product is worth buying. The installation is very convenient, there is no difficulty. It is very suitable for home use, I recommend it
    October 26, 2022
    I want to tell you that I have seen a lot of inverter brands in the market, and I can't tell which brands and models are the ones Jerry recommended to me. The service from ordering to delivery is very good, and I am very satisfied with the effect after installation. I really like the brand of growatt now
    October 24, 2022
    Growtt is a trustworthy brand. It is very convenient for home use, with complete functions, simple operation, and very safe. It is a great choice for interested friends to choose Growtt!
    GROWATT SPF 3500 ES OFF GRID, 3.5KW, 48V, BIG PV INPUT photo review
    October 21, 2022
    I saw that the seller was very careful The product is really good, consistent with the picture, no difference, it's really worth the money, good quality, we will buy it back next time! Logistics is very powerful and highly praised! Fast delivery, cost-effective, full marks!
    GROWATT SPF 3500 ES OFF GRID, 3.5KW, 48V, BIG PV INPUT photo review
    October 20, 2022
    I really like it and support it very much. The quality is very good. It's exactly the same as what the seller described. I'm very satisfied. I really like it. It totally exceeds the expected value. The delivery speed is very fast. The packaging is very careful and compact. The logistics company has a good service attitude. The delivery speed is very fast. I am very satisfied with shopping.
    GROWATT SPF 3500 ES OFF GRID, 3.5KW, 48V, BIG PV INPUT photo review
    October 19, 2022
    The inverter of this brand has been bought and tested before, and the effect is very good. Now we have purchased a lot, and this brand is worthy of our trust. If you are interested in a brand inverter, I highly recommend it.
    Maria Orillos
    October 14, 2022
    I have had this unit running my entire house since November 2021 and have not had any issues. When you follow the manual provided with it and enter the exact specs of your battery(ies), it is an incredible unit! Super simple to install and very easy to program too. Our house is 100% solar power because of this device and it runs everything without any problems. Fridge, washer and dryer, well pump, deep freezer, and lights and it charges all of our devices too (tools and toys). Overall, we are very happy with this purchase!
    Daniel wang
    October 14, 2022
    I am impressed with the professionalism and exectution of the project by this team. Highly efficient, easy to communicate with and definitely know their craft.
    October 14, 2022
    I have bought products from this website for many times. The quality of growatt products is very good. The after-sales service is particularly prompt and trustworthy
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