As an Amazon Associate, this site earns commissions from qualifying purchases. For more details, click here.
When a red light appears on your inverter, it is a sign that something is wrong. But trying to figure out the exact problem can be difficult. Is it the power supply? The battery? Or is there something else? Before you take the inverter to a repair shop, you might want to try the following solutions. In many instances, you should be able to fix this.
A fault light on the inverter usually means the voltage is either too high or low. The light also appears when the inverter is overloaded or there is a battery problem. Check the cable connections and make sure the battery is fully charged.
Voltage is Too High
A high intermediate DC voltage is the most likely reason for inverter over voltage. What usually happens is a high inertia load drops off rapidly, which increases the voltage. Once the DC voltage goes past a certain level, the inverter will flash a red light and stop working.
Solution. If you have a quality inverter like the PowerDrive PD3000, it will have overvoltage protection built in. The system will know when there is a voltage surge and shut down. There might also be an error message indicating the voltage is too high.
A common solution is to reset your inverter. There is a reset button on your inverter or you might have to press the power down for 30 seconds, check your manual.
After rebooting, try the inverter again. If the light persists, turn the unit off and check the voltage supply. Adjust the power source and repair any damaged parts. Call an electrician if you are not sure how to proceed.
Voltage is Too Low
There are many reasons why this can happen. The main supply might simply not have enough power or the internal rectifier bridge is not working properly. If the fuse has been damaged, the supply voltage phase will not be complete. There could also be problems with the contactor and isolator.
Solution. Check the mains power supply. If the incoming voltage is too low, you have to find an alternate power source. If the voltage is sufficient, there is probably a blown fuse or damaged isolator. Check the mains power too for any possible issues. If the power is not enough, you have to use another way to run the inverter or reduce its load.
Temperature Too High
Most inverters will start malfunctioning at temperature above 113 F (45 C). The ideal level is 77 F (25 C) and below, but most will run fine in 80-90 F (30-35 C). But it is not a good idea to expose the inverter to high temperature.
Solution. Sometimes an inverter fault light will appear even before the temperature hits 113 F. The reasons is these systems have safety features built in to warn you of the possible shutdown that may occur if the temperature goes up any further.
The best solution is to run your inverter as close to the ideal range as possible. It does not have to be in the exact spot. As long as the inverter operates in the 80s-90s it should be fine. But if the inverter is on at full load and the temperature soars, it can overheat. In these instances you should install a fan or an AC in the area.
Battery is Not Fully Charged
If the battery is running low on power, the inverter will not have enough to carry its load. The system will overload and it is going to stop running. Unless you connect the system to another power source, it will not function.
Solution. If your system is off the grid or the inverter is hooked up to a battery bank, it must have enough charge to carry its load. A 5000W inverter for instance, can only carry that load if there is sufficient power available to it.
If the battery is not charging it might need to be replaced. We suggest the LISUATELI LifePO4 100ah as it is suitable for solar inverters and has a long lifespan. Once the inverter is fully charged, you can load it to maximum or near maximum capacity. Some manufacturers advise against loading inverters to their limit.
If your inverter is connected to the grid this will not be a problem. As long as there is power coming through the inverter will run. But if you use a battery bank, keep an eye on the power otherwise the fault light will show up.
Wrong Battery Connection
Solution. If you have a 12V inverter, use a 12V battery. If you have a 24V inverter, use a 24V battery. Using the wrong type of battery and inverter combination might cause severe damage.
Solution. If you are going to use batteries to power your inverter, the voltages have to match. Suppose you buy a 24V inverter. The battery voltage must also be 24V. You can either buy 24V batteries or connect two 12V batteries in a series. This will combine their voltages so you have 24V.
If you have the battery and inverter properly matched, the next step is to check the wiring. Most inverter and battery cables use 4 AWG such as the Temco Wires, but yours might be different. Most inverters are also bundled with wires so you will know what size to get.
Connecting the wires is straightforward, but do make sure the positives and negatives are properly connected. Otherwise the inverter might not start. Ensure the cables are secure.
Check the cables periodically. Replace any that has worn out right away. That can cause serious problems or start a fire.
The inverter red light will flash if it gets overloaded. If you have a 4000W inverter and you load 4500W or more, the system is going to shut down. The red fault is going to appear and it will not run until you have reduced the power load.
Solution. Turn the inverter off. Disconnect all loads and let it cool for at least 30 minutes. Turn the inverter on without putting any load. If the inverter runs and the fault light disappears, the unit is fine.
Next, add one device at a time. Let each load run for a minute or so. If the inverter keeps running, load another. Keep doing this until the fault light gets triggered. Using this method you can find out which load is causing the problem.
That particular load might be damaged or is causing the system to overload. You should also check the connection. It has to be plugged in correctly to avoid problems. You also have to make sure the inverter is installed correctly.
One more possibility is that the inverter has suffered some sort of hardware failure. This can happen for various reasons – wear and tear or some component got damaged – and the best recourse is to take the inverter to a service repair center.
If your inverter is old and the fault light keeps appearing, hardware is more likely. If it is now or in good condition, other problems might be behind it. It is a good idea to try the various solutions given here first.
How to Prevent Inverter Fault Light
Install the inverter as indicated in the manual. Before connecting any device, read the guidelines on what you can and cannot load.
Inverters have continuous and surge watt capacities. Take note of both and do not exceed them. Doing so can cause permanent damage to the inverter and the appliance or device you connected.
If the battery is old, use a multimeter to check if it is still running. If the result is 10.5V or less, the battery is dead and must be replaced. Go to the inverter manufacturer website for information on what type of battery can be used with it.
If you are using the inverter from the mains power, check the cord. It must be plugged securely. If you are using an extension cord, it might come loose. The cord has to be long enough for the system to work.
Inverters are often said to be the most vulnerable pat of any solar powered system. While this is to some extent true, care and proper use will prolong its lifespan.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.