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An inverter converts DC (direct current) into AC (alternating current), which makes it useful for solar powered homes and RVs. But what happens when your inverter has no AC output? Inverters are made up of many different parts, so figuring out what is wrong can be a challenge. We have compiled a list of the most common reasons and solutions.
If the inverter has no AC output or the DC voltage drops, there is not enough power available. The battery is probably dead or damaged. It is also possible the inverter is overloaded and cannot handle the demand.
How to Quickly Fix Inverter No AC Output
- Use a true RMS meter like the Fluke Multimeter to check the DC voltage. If it is out of normal range (must be around 10.5-16 volts) the battery is probably damaged. If in normal range, go to step 2.
- Disconnect the battery and all loads. After half an hour, reconnect the battery. Reset the inverter.
- Turn on the inverter but do not add any load. Check the voltage again. Add one load at a time and check the AC output.
- If the first load has no AC output, try another. If the appliance runs, you know that the first device loaded is the problem. If no devices work, there could be a battery circuit issue.
How to Check the DC Voltage
It is normal for the DC voltage to drop, but it has to be no more than 2%. Anything higher than that and there is an issue. If your inverter has no AC output or is too low, look at the DC voltage.
The voltage has to be 10.5 to 16V. You can use a multimeter to get a reading. If the voltage is between those figures, it is not the problem. If the voltage drops lower or is erratic, check the battery. It might not be supplying the needed power.
If the battery is new, unplug it from the inverter. Wait for 30 minutes and reconnect it to the inverter. Reset the unit. This ought to clear the system up and you can try again. If this does not work, disconnect all loads from the inverter and then reboot. After rebooting, use a true RMS meter to check the voltage.
A lot of problems with inverters can be traced back to its power supply, the battery. There are many types of issues that can come up, and almost all of them can result in faulty AC output.
Battery not fully charged. Remove all the loads and charge the battery until it is full. How long this takes depends on the battery and power source. Once full charged, add the load one at a time and keep an eye on the output. If the battery has not been damaged, it will work. It also helps to use a quality inverter. Our choice is the MXMoonFree 5000W inverter because of its capacity and reliability.
Battery will not charge. Make sure the charger is connected tightly to the battery. Check the power source too. If the battery is old it might need a replacement already. As batteries get older, they lose charger faster and take longer to replenish.
Battery wire is loose, rusty, wrong size or worn out. If the wire is loose, tighten it. If the cable is worn out, corroded or the wrong size, replace it. Consult your owner’s manual for the right wire size. When installing the battery, ensure the terminal connections are correct.
Battery is overloaded. Its capacity is in ampere hours (ah). If the inverter load is greater than the battery capacity, there will be no output. An inverter is only as good as its power source.
For instance, if you have a 2000 watt inverter running a full load and a 12V 150ah battery, the load will not run. 150 ah at 12 volts is only 1800 watts, less than the 2000 watts minimum required.
12 volts x 150 ah = 1800 watts
The battery and inverter must both be capable of supplying the required power to carry the load. If the battery is too small, the inverter will not be able to run the load even if it has the capacity for it.
Inverters have a limited load capacity. Once you reach that point, the system will no longer be able to function. It will produce all kinds of error messages and may no longer have any AC output.
Inverter capacity is measured in running watts and surge watts. Running watts is the amount the unit can load at the same time. If an inverter has a 2000 watt capacity, you can load almost up to 2000 watts on the system without overloading it.
Note that we say almost up to 2000 watts. You should not load an inverter to its limit. Always leave room for a power surge just in case.
The surge watts refers to its surge watt capacity. Usually it is twice the running watt limit, but an inverter can only provide this for a few seconds. For example, a 2000 watt inverter might have a surge watt limit of 4000 or 6000 watts.
Appliances like refrigerators and microwaves have surge requirements, so that has to b factored in. If your fridge has a 4000 watt surge requirement but your inverter is only capable of 3000 watts, the fridge will not run. Forcing the inverter to run will overload the system and cause output errors.
If you are sure the inverter is not overloaded and the power supply is sufficient, the load could be the problem. If the appliance or device is damaged, you will not see any output.
The solution is to find which load is causing it. Disconnect all loads from the inverter. Reset the inverter for a fresh start. Now add one load at a time and check the output. If there is AC output, add another device.
Keep adding all the devices you regularly load. Eventually you will come across the device that is causing the problem. Once you find the source, determine if the appliance or device is really damaged or if the inverter is overloaded by this point.
Check the Wiring
The thicker and shorter the wire, the lower the voltage drop. The longer and thinner the wire, the higher the drop.
Inverters come with their own wire so you do not have to second guess. If the AC or voltage output is dropping, check the wire. If you are using the one that came with the inverter, it is the correct size. But it might be loose or worn out. In that case you have to replace the wire right away.
When shopping for an inverter wire, make sure that it is exactly the right size. If you are using a 5000W inverter for example, check the manufacturer for their recommendation.
Related. How long should inverter cables be?
Change Inverter Settings
If the inverter has a power saving or idle mode, it could be mistaken for not giving any output. If power saving or standby mode is enabled, the inverter will not carry any load or have a huge voltage drop.
Check the owner’s manual if it has any such features. Disable it and try loading devices again. While these features are useful, it is easy to make a mistake and leave it on.
Most inverters today have some sort of power saving capability. But its implementation varies so you have to check the instructions that came with your inverter.
Inverter Hardware Problem
This can mean a faulty power on switch, a damaged reset button or an internal failure. Inverters are complex machines and things can go wrong.
Usually it is easy to tell if there is a problem with the switch, it will refuse to turn on. If this is the issue, you have to take the inverter to a professional and so that an expert can replace the malfunctioning part. This is not something you should do yourself because it requires tinkering with the internal workings of the inverter.
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