About giandel inverter display "LO" and "OL", how to solve and repair.

Giandel Inverter input under-voltage alarm:

When the input DC voltage is lower than 10.1V (20.2V), the buzzer will whistle intermittently to remind that the inverter will go into the undervoltage protection.

Under-voltage Protection(“LO” error code):The inverter will automatically shut down when the input DC voltage is lower than 9.8V(19.6V).The buzzer will whistle continuously and the green light is off, red light is on.

About the LO situation, there are some troubleshooting tips to help you find the reason:

1.Please try to fully recharge your battery about 8 hours and then test again.

2. Please use all of our standard cables. If you use your own cable, please confirm the cable size and length, too thin and long cable length will pull down the voltage.

3. Please use the suitable capacity of the battery. About the battery capacity recommendations for each size inverter, please check out the other post.

4. Are multiple batteries used? Please check the wire gauge of the connection wires between multiple batteries. The bridge wire between the batteries should be thicker, otherwise the input voltage will also drop down.

5. And please check the voltage of your each battery after they are fully charged, if there is a problem with one of the batteries, it will also pull down the voltage.

6. Did you add any inline fuses or circuit breaker between battery and inverter? If the amps of inline fuse or circuit breaker are not large enough, will also pull down the voltage. So if you add the inline fuses or Circuit Breaker, please remove them to test the inverter.

7. Please check whether there is corrosion or other dirt on the positive and negative terminals of the inverter or the battery. Please clean the positive and negative terminals and test again.

8. Please check is there a cable loose lug connection in the terminal of the inverter and battery.

9. Please use a volt meter to test the voltage of the inverter's input terminal when the inverter shows "LO" and beeps . Then you will find the reason.

Hope these trouble shooting tips can help you find the reason and resolve the problem.


Usually there are three reasons for this “OL” failure situation with no load connected:

1. Accidentally connected other AC output systems (shore power, generator) and did not disconnect the inverter, causing AC output back feed into the inverter.

2. A load far exceeding the output power protection value of the inverter is connected, causing excessive power impact to the inverter.

3. Long term full-load use will cause damage to the inverter, resulting in no load OL fault.

Regarding the no-load “OL” failure, how to fix it yourself?

There are usually two reasons for this no-load OL failure:

1. Misconnection of other AC output systems (shore power, generator) without disconnecting the inverter, causing the AC output to feed back to the inverter.

2. The load far exceeding the inverter output power protection value is connected, causing excessive power impact on the inverter.

In fact, this kind of failure is not irreparable, but requires professional technicians to repair it.
Please open the inverter and check whether the components are burned, especially check all the Mosfet tubes. This is usually the case with burnt Mosfets.
If the AC power is accidentally connected to the inverter, the inverter will appear no-load OL. He tried to open the inverter and found that the mosfets were burned. After he found the same mosfet and replaced it, the inverter worked fine.
Other models also work: IRF3205 or Infineon 75N60

You are welcome to know about our Giandel inverter at any time: www.giandel.uk