Cobra Power Inverter Problems & Troubleshooting

By:Michael Johns

Cobra power inverter problems

Having problems with your Cobra Power Inverter?

I’ve been there too my friend.

It’s incredibly frustrating when your Cobra power inverter isn’t working properly.

Especially, if it’s not producing any output at all!

Fortunately, there are a number of common problems that are usually quite easy to fix.

Let’s go through the most common problems with a Cobra inverter and how to fix them.

Low Output Voltage

The most regular problem is a low output voltage the reason for this is usually a system overload.


Overloading your inverter can lead to a low output voltage. This means there won’t be enough energy flowing out to run your appliances. In fact, it means you are trying to draw too much power and the inverter can’t handle it.

To solve this you should immediately reduce the load you are trying to draw from the inverter. This means disconnecting appliances until the system is no longer overloaded.

No Output Voltage

Another issue you might find is no output voltage at all! This means there’s no electricity flowing out of your inverter into your appliances. Nothing will work in this case.

Low Input Voltage

A lack of output is often due to a low input voltage. This means there is not enough force of electricity going into your inverter. The number 1 cause for this is low battery or faulty wiring.

Basically, not enough electricity is flowing at one time from the battery to the inverter. You should fully charge your battery and check the cables are connected properly.

Short Circuit

A short circuit will also result in no output. A short circuit is when two wires or components unintentionally touch or become connected. This means the current is being diverted in the wrong place and does not reach the intended output of a circuit.

You should carefully check the cables and components for proper operation. Also, ensure your inverter is completely dry and there is no water in the circuit.

Inverter Switched Off

This is a simple one. Are you sure your inverter is switched on? Make sure to turn it on otherwise there will be no electrical output!

No Power to Inverter

No power going into the inverter will mean there is no output. It’s obvious but can occur without you realizing. Take the time to check all your cables and connections between the battery and inverter.

Reverse DC Polarity

Reverse polarity is when your circuit is wired backward. This happens when the system is wired up incorrectly. You can spot this if the ‘hot wire’ (red/positive) is wired to the neutral side (black/negative) and the neutral side is wired to the hot wire. 

No Output Voltage After Prolonged Use

If you have been running your inverter for a while and suddenly encounter no output voltage then it is likely due to a thermal shut down.

Thermal Shutdown

Your inverter is overheating. You should allow it to cool off for at least 30 minutes. 

When you want to power it back on, you need to reduce the continuous load so it does not overwork the inverter again.

If overloading is not the problem then try to improve the ventilation. Don’t place the inverter in an enclosed space. Plus check the vents and fans are not obstructed. You also might want to think about reducing the air temperature and avoiding using the inverter in direct sunlight.

No Output Voltage ‘Protect’ Light is On

When the protect light switches on it means the inverter is automatically guarding against an issue. It will kill the output voltage until you fix the problem.

High Input Voltage

The protect light is often down to an overvoltage problem. This means you are trying to input too much voltage for the inverter. For example, you have a 12V inverter connected to a 24V battery. The inverter will automatically protect itself as this would lead to a system overload and overheating.

Ensure your inverter input voltage matches your battery voltage.

Low Battery Alarm on All the Time

The low battery alarm is an annoying sound. It is designed to alert you to a low battery but what if you have charged your battery?

Poor DC Wiring

The first thing to check is the wiring between the battery and the inverter. Make sure the connections are intact and that you have used the right gauge/size cables.

Poor Battery Condition

If the wiring is correct then it’s time to check your battery condition. Deep-cycle batteries do not last forever, they have a shelf life. Plus lead-acid batteries can be damaged if you fully discharge them. Be sure to check the condition of your battery to ensure it is working correctly.

No Battery Charge

The low battery alarm will sound if you have low or no battery. Make sure you have actually fully charged your battery!

Wrong Cable Size

The incorrect gauge cables will result in a low voltage in your inverter. This can also trigger the alarm as the inverter thinks the lack of voltage is a low battery signal.

Check the user manual and technical information for the correct cable size.

Final Words on Cobra Power Inverter Problems

I’m sorry to hear you’ve been having problems with your Cobra power inverter.

Usually, they are very robust pieces of equipment. 

Don’t panic and take the time to identify the issue. Quite often it is an easy fix that can be done in a matter of seconds.

Just be sure not to ignore the problem as it can present a safety risk and damage your appliances, inverter, or battery.

Can’t fix the problem? Take a look at a replacement with my guides to the absolute best inverters and car power inverters.