Are Power Inverters Bad For Your Car?

Should you get a power inverter for your car? Will an inverter damage your car? Here's the ultimate guide about power inverters.

Power inverters are a divisive subject. You’ll find some people claiming they’re the best thing ever. Others will tell you to avoid them like the plague.

So, what’s the truth of the matter? Is there any reason you should get one? And will a power inverter drain your battery?

In short: nobody can stop you from getting a power inverter, but if it’s misused, your car will suffer.

With that bottom line up front dealt with, let’s get into it.

Table of ContentsShow

What Is A Power Inverter On A Car?

Power inverter

Power inverters are aftermarket electrical transformers available from most parts stores.

There are two broad categories of power inverters: plug-in and wired-in.

Plug-in models connect through the cigarette lighter outlet or USB port. They then draw their 12 Volt input through there.

Wired-in power inverters connect directly to the battery. They require professional installation but should be more effective. Of course, they’ll cost much more.

The power inverter takes the car’s 12-Volt DC circuit and transforms it into a 110-, 120-, or 130-Volt AC circuit. That’s the same as your home. In different countries, the output voltage varies according to the normal mains.

As a result, you can charge or run pretty much any device using it. These could include:

  • Laptops
  • TVs
  • Games consoles
  • Plug-in fans
  • Vacuum cleaners
  • Lamps
  • Power tools or their charging ports
  • etc.

Sounds too good to be true? Well, it often is.

Do Power Inverters Affect A Car’s Battery?

Car Power Inverter

People hesitate here by wondering, ‘Will a power inverter damage my car?’

In short, a power inverter will almost certainly damage your car – if misused!

Using the power inverter while driving shouldn’t have too much of an impact (provided the Wattage isn’t too high!). However, using it when the car’s off will almost instantly kill your battery.

Your battery is a somewhat surprisingly fragile thing. If it discharges beyond 12 Volts, it’s considered dead and needs jump-starting.

Power inverters come in many sizes, but they undeniably draw power. The higher the Wattage on the inverter, the more it draws.

Thus, a power inverter might give your car battery an early (sometimes very early) death.

How To Choose A Power Inverter

If you’re absolutely set on getting a power inverter, here are a few things to watch out for.

Please remember that it’s still not recommended, but if you’re going to anyway, make sure you do it right.

Turn The Cursed Thing Off!

Turn Off Switch Off

This part cannot be stressed enough.

When you aren’t using the power inverter, turn it off. Ideally, unplug it from your car completely.

If you’re parked up, doing this prevents a parasitic drain from killing your battery. If you’re driving, the electrical systems can focus on the engine and regular appliances.

It’s for the best. Don’t get one if you think you’ll forget to turn your power inverter off.

Get The Power (Wattage) Right

Wattage Power

You need to know what devices you’re going to be running from the power inverter before you buy it.

For example, if you want to run a TV and DVD player for your kids in the back seats, what’s their total Wattage?

Let’s say the TV puts out 50 Watts and the DVD player 20 Watts. (These are guesstimated figures.)

Calculate the total power (Watts) the inverter needs to put out. In this example, it’s 70 Watts. It’ll be different for you.

It’s then sensible to add a 10% buffer for safety. That would take the figure to 77 Watts.

That means you should buy a power inverter with at least 132 Watts.

If you don’t, it’ll regularly trip out as the in-built fuses protect its circuitry.

Keep The Area Around The Power Inverter Well-Ventilated And Cool

Cooling

A power inverter is a powerful electrical device. It must be kept cool and in a well-ventilated area when plugged in.

Inadequate environmental control will mean overheating and potential failure. In worst-case scenarios, they could even catch fire.

To avoid this, don’t put them in the glove compartment, center console, near the heater fans, or cover them with anything. And, as mentioned many times, turn them off!

(In the same vein, very low temperatures might also impede the inverter’s performance.)

Extra Things To Know About Power Inverters

Here are a few more things you should be aware of before buying one.

  1. At start-up, motors temporarily need more power than their rating. If you want to run motors from a power inverter, look carefully at the specifications.
  2. Cheap, low-quality inverters produce a very crude AC waveform. This isn’t suitable for certain devices. For example, if you wanted to power a microphone or speaker system, you might hear a loud buzzing sound. As an alternative, look at true sine wave inverters. They’re more expensive but tend to reduce this kind of problem.

Who Should Get A Power Inverter?

Most people don’t need a power inverter.

One exception would be if you badly need to charge a particular device during a long journey. Again, though, in most cases, you should wait until you arrive or do it before you leave.

Another exception might apply to remote manual laborers. For example, a well-wired-in power inverter might suit you if you need to take your truck out into the wilderness to cut trees with a giant saw.

That said, evaluating your needs and weighing the risks is still crucial. It might be much less risky to buy a generator and take that with you. You don’t want a power inverter to kill your car battery and thus mean you’re stuck in the middle of nowhere.

Should You Get A Power Inverter?

Thinking

This article certainly hasn’t recommended getting a power inverter. The truth is, installed and used sensibly, power inverters should be fine.

However, most people don’t install or use them sensibly and give themselves all sorts of problems.

Thus, the realistic answer would probably be ‘no’. Don’t.

Nowadays, almost every car on the road has USB or 12-Volt adapter connections. If charging your phone is all you need, you don’t need a power inverter.

It’s the same for many other appliances like DVD players or minifridges – just buy an in-car version. There’s no real need for a power inverter in most cases.

Note: you should still know that certain in-car appliances are known for rapidly flattening batteries. One of the most well-known examples is in-car fridges that typically plug into the cigarette lighter.

Power inverters aren’t usually worth it. The risk to your battery (especially from leaving it on while the engine’s off) is much greater than the reward: a little extra charge for your device.

Save yourself the hassle, and remember to charge your devices before traveling.

Simples.

This should be the deciding factor: will you remember to turn it off? If yes, okay – go ahead. But if not? It’s not worth it.

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Benjamin Kitchen

Ben is an automotive author from England. With experience in a fast-fit garage, he's an IMI-qualified light vehicle technician. He aims to help drivers worldwide with common automotive problems. You’ll often find him working with his 1.2 Vauxhall Corsa – it may have a tiny engine, but in eight years it's never once let him down!

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