How to buy a power inverter for your car or truck

Don’t buy the wrong type of inverter for your car or truck

Here’s what you need to know before you buy a power inverter for your car or truck

Step one: Know your sine wave requirements before choosing a power inverter for your car or truck

Pure Sine wave versus modified sine wave power inverters

DC to AC power inverters can output AC ways two ways; Pure Sine Wave or Modified Sine Wave. Direct current moves in one direction whereas alternating current changes direction polarity about 60 times per second.

A pure sine wave rises smoothly to its peak voltage, falls smoothly to  0 voltage at which point it changes direction, again in a smooth wave. A modified sine wave, on the other hand, rises and falls abruptly in stair-step motions.

A pure sine wave inverter produces power that’s closest to the type of power in your home. It’s best for running for running sensitive electronics in your vehicle. For example, you’ll want a pure sine wave inverter if you’re going to power a laptop, power tool battery charger, TV or other electronic devices. So check the requirements before you buy.

Items that require a pure sine wave:

Power tool battery chargers
Medical equipment, such as CPAP machines
Appliances with AC motors: Microwaves and refrigerators
Sensitive electronics
Laser printers
Newer TV’s
Appliances with electronic timers or digital clocks

Pure sine wave inverters are more energy efficient than modified sine wave inverters and they cost more. Don’t think you can get the same results with a cheaper modified sine wave inverter.

Step two: Know the wattage of the devices you want to run

Power inverters are rated in output watts at 120-volts. Here’s an example of the power you need to run a 15-inch Macbook. While in use, a 15″ Macbook consumes approximately 87 watts. But the actual wattage depends on the screen brightness, the software you’re running, the graphics card installed and whether it’s charging In this case, you’d want at least a 100-watt or 120-watt pure sine wave inverter.

All inverters list a continuous rating and a surge rating. The surge rating is usually specified as X number of watts for X number of seconds. The surge capacity will varies quite a bit between inverter makes and models. In fact, the surge rating can be as little as 20% to as much s 300%. Generally speaking, a 3 to 15-second surge rating is enough to cover 99% of all appliances – the motor in a pump may actually surge for only 1/2 second or so.

As you might guess, the units with the lowest surge rating are also the least expensive. If you’re running just a laptop, you can get by with a low surge rating. But if you are running a power tool that has a high initial surge and draws more wattage when it’s under load, you’ll have to dig deeper to buy an inverter with a higher surge rating.

Step 3: Know the fuse rating on your power port

The power ports (cigarette lighter) on older vehicles were often fused at 7 to 10-amps. Since amps times volts equals watts, those power ports are only capable of producing 84 to 120 watts maximum. That may sound like plenty of power to run an inverter, but even the best inverters aren’t 100% efficient. Depending on the make and model (and price), power inverters can consume up to 20% to 30% of the incoming power to make the conversion from DC volts to AC volts. So a cheap inverter plugged into a 7-amp power port may only provide 58 watts; not enough to run many laptops.

Newer cars and trucks, on the other hand, have 15 and 20-amp power ports, eliminating the problem altogether.

Step 4: How many AC and USB outlets do you need?

This one is pretty simple; the more outlets you need, the more it’s going to cost.

Let’s look at a popular power inverter at a very reasonable price

BESTEK 300W Power Inverter DC 12V to 110V AC Car Inverter with 4.2A Dual USB Car Adapter MRZ3011BU-RD-US-E01

BESTEK 300W Power Inverter

PURE SINE WAVE
300 Watts continuous AC power
700 Watts surge
2 AC outlets and 2 USB ports (2.4A)
Cooling fan system makes the car power inverter very silent when operating,and the fan runs faster when the device gets warmer or output power exceeds 70W.
18-Month Warranty

TIp to hook up a power inverter for your car or truck

A low wattage mobile power inverter plugs directly into the power port in the cabin, while high wattage power inverters connect to the battery posts. Most late model vehicles have power management systems that monitor current draw from the battery. In those vehicles, you should never connect an inverter to the battery terminal. It must be connected in series so the power management system can also monitor the current draw of the inverter. Please keep that in mind and get professional help if you don’t understand how to install your inverter in series.

©, 2023 Rick Muscoplat