It’s happened to me too.
To start with, everything is running great.
You’re able to run all your appliances, charge your phone and laptop, no problem.
Then one day your inverter shuts down.
So you head on over to investigate, switch it on and off again.
That seems to do the trick, but then just as you sit down the inverter shuts off again.
But why?? Why isn’t it working properly!?
Well, you’re not alone here and it is quite a common issue to have because there’s a number of reasons your inverter shuts down.
Together, let’s go through the issues you might be facing, plus how to identify and fix them.
Inverter overload is the number one reason it shuts down. The safety features are designed to kill the power when your inverter detects any signs of overloading. This is because if an overload was allowed to continue it could start to melt the circuit and catch fire!
Have you attached any extra appliances to your off-grid electrical system recently that might be trying to draw more power? Or do you attempt to turn on multiple electronics at once leading to a massive surge in wattage? Most appliances surge in power for a few seconds when you first start them up. If it’s hot outside something like a refrigerator can allow me to draw more power to cycle on more often too.
If you think this might be the problem then test it out by removing high powered appliances from your inverter one at a time. You should take the time to total up the wattage of all your appliances you are running and compare it to the inverter running wattage. A wattmeter can be a useful device for working this out.
An inverter will shut down when it starts to overheat. Once again this is to protect the circuit from melting and fire. An inverter will overheat when it is overloaded but there are a number of other reasons it can overheat too.
- Direct sunlight – Make sure your equipment is not in direct sunlight. Even if the air temperature is cool, direct sunlight can heat things up very quickly particularly in a car, RV, or truck
- Air temperature – Hot summers can also cause overheating. Inverters need cool air to run cooling systems correctly and dissipate heat.
- Ventilation – Poor ventilation such as an enclosed space or obstruction to the cooling fans means air can’t flow to dissipate heat.
If you experience this problem then try moving the inverter to a well ventilated cool area.
3. Low Battery
This might sound like a no brainer, but are you absolutely sure your inverter battery is well charged?
It can be a little tricky to know if a deep cycle battery has full charge so double check this. You might consider getting a battery display monitor so you can keep track of charge levels.
Lead-acid batteries can easily be damaged and not charge very well if used incorrectly. For example, you should never completely discharge a lead-acid battery. In addition, flooded batteries need to be topped up with water regularly.
Double check your battery charge level and make sure to maintain it properly.
4. Loose Cables
Loose cables and connections between your inverter and battery can cause it to shut down. This is because voltage can drop when you have loose wires as the electricity can flow efficiently.
Inverters have auto shutdown settings when low voltage is detected as it is a sign of low battery levels. It might think you have a low battery but it is just a loose cable. You might also hear a squealing sound with this issue.
Be sure to check your positive and negative connections regularly.
5. Wrong Voltage
As I mentioned above, the incorrect input voltage will instantly shut off your inverter.
Low voltage, known as undervoltage, means electricity is not flowing with enough force so there is insufficient to run your inverter.
High voltage, known as overvoltage, is when electricity is flowing with too much force and your inverter can’t cope.
Inverters are designed to work with a particular input voltage usually 12V or 24V. If you are using a new battery ensure your battery is the same voltage as your inverter. E.g. 12V inverter with 12V battery. You can’t use a 12V inverter with a 24V battery as it will lead to overvoltage. And vice-versa for undervoltage.
You might also experience voltage issues when connecting batteries in series. When you connect batteries in series the voltage increases, in fact, it doubles! For example, two 12V batteries in series will output 24V to your inverter. To keep a constant voltage you need to connect batteries in parallel.
6. Wrong Cable Size
Selecting the correct cable size and length for your inverter is important. You will get various issues with the wrong size wires between your battery and inverter. Here’s what this could mean:
- Cable too long – The longer a wire the more resistance occurs which lowers the voltage. Always ensure your cables are less than 10ft (3m) to reduce this issue.
- Cable too thick – A cable that’s too thick will also reduce the voltage and stop electricity flowing efficiently.
- Cable to thin – A wire that’s too thin will not be able to handle the amount of energy flowing through it and could overheat and melt.
It is best practice to make the inverter cables as short as possible and as thick as your system will allow.
7. Not Enough Sunlight
Finally, this last one applies to solar panel users only. If your solar panels are not getting enough sunlight they won’t be able to supply enough energy to your inverter.
This can be an issue for both off-grid and grid-tie inverters. An off-grid inverter that uses solar panels needs plenty of sunlight to charge the batteries for the inverter to run.
It is even more important for a grid-tie inverter as it will run based on the electricity supplied by the solar panels. If there’s not enough solar power the inverter may shut down and you will draw power from the mains grid.
You can increase the amount of sunlight hitting your panels by adjusting the position and angle. In my experience, during winter you can over double your energy capture by angling your panels at 45 degrees towards the sun, rather than laying them flat.
Final Words on Inverter Shuts Down
Ahhh, inverter shut down. It can be such a nightmare!
Usually, there’s a simple explanation, so do some investigating before buying a new one.
Most likely it is due to an overload, cooling problem, or voltage fluctuation. Be sure to check your power draw and cable connections first. Particularly in vehicles, cables can come loose over time as you drive around.
If you feel like it’s time for an upgrade then check out my guide to the Absolute Best Power Inverters.
Thanks for reading.
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.