Do Inverters Drain Battery?

By:Michael Johns

low battery inverter

Keen to know if a power inverter drains your battery?

The short answer is YES!

Inverters require a battery to work as they have no power source of their own.

The inverter is simply a device used to convert the Direct Current (DC) from a battery into Alternating Current (AC) need to run most appliances. AC electricity is what you get out of the wall plug at home from the mains.

It is best to use an inverter with a deep-cycle battery that you find in RVs, boats, and solar systems. 

You can also use an inverter with your car starter battery. As the inverter will drain your car battery you must keep the engine running while using an inverter with a car. If you don’t run your engine, the inverter can drain your battery in less than 30 minutes. This will leave you unable to start your engine and damage your car battery. As long as you run your engine it is safe to use an inverter with your car battery and the engine keeps the battery charged.

How Long Will a Battery Last With an Inverter?

The length of time a battery will last with an inverter depends on two things – battery size and the amount of power you draw.

It is not the size of inverter that counts here. What drains the battery energy is the appliance or device you plug into your inverter such as a TV, laptop, lighting, fan, coffee maker, etc.

To calculate how long the battery will last you need to divide the battery capacity in Ah by the amp you want to draw. If you want to learn more about this then read our in-depth guide to ‘How Long will a Battery Power an Inverter?’

Do Inverters Drain Battery When Not It Use?

Yes, an inverter can drain your battery when no load is connected.

That means even if you have no appliances plugged into your inverter it can still use electricity. 

If you leave your inverter switched on it will use energy to run its own internal systems such as cooling, screens, and safety protections. Eventually, it will deplete your battery over a long period of time.

When not in use you should always switch your inverter off or completely disconnect it to ensure it doesn’t drain your battery.

Do Inverters Waste Power?

Inverters are not 100% efficient so you will get wasted power. Generally, inverters are 90% to 95% efficient. Some power is wasted during the conversion from DC to AC power.

This means you should take into account this power waste when working out how quickly an inverter will drain your battery. I usually work to an 85% efficiency to give a safe calculation.

Why Does My Inverter Battery Drain So Fast?

There could be a number of reasons your inverter drains your battery so quickly.

The most common reason is excess usage. This means you are drawing a lot of energy from your battery to run your appliances and electronics. The more device or watts you use with your inverter the faster it will drain your battery. 

Adding to this, the more often you use a battery the more it will wear out. This means it will be less efficient in storing and delivering energy. A deep-cycle battery has a limited lifespan of around 6 years. This can decrease with excessive usage as they can only be recharged a certain amount of times. Depending on the battery you can get between 200 to 3000 charge cycles out of a deep cycle battery.

Final Words: Do Inverters Drain Battey

As we now know, inverters do drain your battery.

The way inverters work is to draw energy from your battery and convert it into AC power for your appliances.

This makes it important to make sure your battery is charged before you use your inverter.

If you use a deep cycle battery then make sure you charge it from an external hookup or solar panel system.

To use an inverter with your car battery you should keep the engine running in order to stop the inverter from draining your vehicle starter battery.