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How to Solve That Off Grid Inverter Can’t Be Switched On Or LCD Screen Is Off

How to solve that off grid inverter can’t be switched on or LCD screen is off

There are several situations that cause this phenomenon

SPF 3500-5000 ES

Situation 1:
LCD Screen is off, but fans are working and Fault Led light is blinking


1.Most of time, wrong firmware has been flased by clients.


Once you fail upgrading, you just can replace new control board or if you have third party device called Emulator , you can flash it agian.

2. Control board is something wrong( I seldom meet the situation )

Replace new control board directly

Situation 2:
LCD Screen is off, only fans are working

Fans are working normally, it means that SPS circuit ( yellow rectangle) on mainboard is normal


Either it is caused by control board or mainboard, you need to do further test.

Test 1:

Only connect PV into inverter without Battery system and utility, and observe if LCD can be on. If LCD can be on, it can demonstrate that contorl board is ok, you can get the conclusion that it is caused by mainboard

Test 2:

Swap control board from normal inverter, and see if inverter can be on, if yes, so it is caused by control board, if not, definitely it is caused by mainboard

Situation 3:
LCD Screen is off, and fans are not wokring at all

Test 1

Please use multimeter to test if battery voltage is normal, If normal , you can do test 2. If abnormal, please test the inverter with normal battery .

Test 2

You should check the connection wire( red arrow from inverter switch to mainboard ) from inverter switch to mainboard firstly, this wire is used to transmit the starting signal to SPS circuit ( Power supply circuit) , once broken, you can’t switch on inverter

You had better swap the connection wire from normal inverter and exclude wire issue.

Test 3

If connection wire is good and battery is normal, but inverter still can’t be switched on, you can check if fuse is broken on mainboard. If fuse is broken, You can replace new mainboard or replace fuse. What if fuse is ok, definitely the issue is caused by SPS circuit on mainboard or other broken circuit on mainboard. You can replace mainboard directly

Test 4

If fuse is ok, and you have replaced mainboard , it still can’t be switched on, in this situation it may be caused by control board. I seldom meet the situation, most of time, if battery voltage , connection wire , fuse are normal, it is always caused by damaged mainboard.

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