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How Many Watts Does a CPAP Use? Yes you can travel

Traveling and dealing with a CPAP machine isn’t the easiest thing. Truckers are essentially travelers and yes, you can travel with your machine. So how many watts does a CPAP use?

It’s no secret that many commercial vehicle drivers and other travelers struggle with sleep apnea. DOT did propose a rule in 2017, but (thankfully) withdrew the idea in favor of providing drivers with more info.

How many watts does a CPAP Use

A standard CPAP machine without a humidifier uses as low as 53watts depending on machine settings. Advanced CPAP machines equipped with integrated humidifiers will use 90 watts.

Realistically, the power requirements for CPAP machines are as varied as the machines themselves. The power requirements I’ve provided above is an average based on the most common and popular CPAP machines in use today.

Related: Accessories For Truck Drivers, 29 Ways to Customize Your Comfort

In the past CPAP machines used only about 30-60 watts. But newer more advanced machines have a lot more features and gather more data to help sleep apnea sufferers.

An example would be the Resmed AirSense 10 that gathers therapy data and has space for an sd card.

Helpful CPAP Accessories

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Running a CPAP on an Inverter

Most CPAP ventilators feature a DC option to run on a (check our list of best power inverters here). When your machine has one, you can connect it to a power cell. For AC-only units, you may use a small inverter.

175-watt inverters can make your CPAP run for 3-5 nights. However, this depends on the pressure setting that you are using and on the type of machine you have.

If you don’t use your CPAP too much, a small inverter will be enough to power it. But, if you use the humidifier, it can be a bit complicated.

There are two types of CPAP machines. The first one is the AC-only model and the second one is the DC powered version. If your machine has two cords, it is AC powered. If it only has one cord, your machine runs on DC power.

AC-only CPAP machines shouldn’t be run on an inverter. It could damage your CPAP. Inverters produce Modified Sine Wave. This can damage AC-powered machines.

If your CPAP machine is a DC version, it’s safe to use the ventilator with an inverter. If you own an AC powered unit and you just use the blower, it is okay to use an inverter.

Can You Run a CPAP Machine on a Generator?

In general, the answer to this question is “No.” Today, most generators produce modified sine waves (read more). This is why generators must not be used with AC-powered CPAP ventilators.

However, if your generator has permanent magnets, it may be able to produce suitable power.

A generator allows you to convert the provided current to another voltage by using a transformer. With generators, you  need higher levels of insulation because of the massive amount of voltages required when supplying a fixed amount of power.

Also, modified sine waves cause heat to build up inside the load. When this happens, your transformer may burn out.  Remember that any machine with a power transformer needs a power source that produces pure sine waves.

If you are facing this issue, it is best to use an accumulator or battery instead of a generator.

Do CPAP Machines Have Battery Backup?

Today, most CPAP machines have built-in batteries. When other power sources are unavailable, backup batteries will power your CPAP machine. If your ventilator does not have a battery backup, you can use a battery pack instead.

With the DC cable adapter, you can connect your ventilator to lithium-ion battery packs. Battery packs are more portable and lighter than deep-cycle batteries. But, you must recharge them every 1-2 nights.

Most CPAP machines with integrated batteries are more expensive than regular models. However, your ventilator can be used for more than 8 hours even after a power outage when it has a battery backup.

Also, pressure settings do not affect backup batteries that much. This implies that you don’t have to worry about anything when you increase the pressure option whenever you are running your CPAP machine on backup battery power.

If your CPAP machine does not have a DC output, use a DC to DC adapter in order to solve the issue.

When you go overseas, you need to consider the AC current available in that country. In the United States, it is 110 volts, but in other countries, it is 220 or 240 volts.

This is when a battery backup can come in handy. However, remember that you will need an inverter if your CPAP machine doesn’t have a DC outlet. Typically, battery backups require an inverter to switch current from DC to AC.

Can I use a CPAP with 12 volt DC Power ?

In case you forgot, the 12 volt DC power is the same power supply that’s available in any vehicle cigarette lighter.

Yes you can and in fact you have a couple of different options available to you.

The first option is to simply get a power cord. The power cord should have the connector for your specific machine on one end and the cigarette lighter connector on the other end.

If you’d like to get a bit fancier, you can purchase a 12 volt battery kit. These kits will work not only as a battery backup for your machine but will also allow you to connect it to a cigarette lighter adaptor.

electrical powerlines

How much power does a CPAP need?

This section is going to be super nerdy with electrical stuff (you’ve been warned!). 

If you’re super into it, you can read even more about detailed electricity stuff here. If you’re new to understanding electrical stuff and electricity this is a good basic guide.

First, you must know how fast electric current flows on your unit. In other words, know how much ampere your CPAP uses at 115 AC. You then have to calculate your unit’s required current at 12 Volts.

At a 20 cm water pressure setting, a CPAP machine that draws 4.5 amperes needs 36 amp-hours in 8 hours. So, your battery should be at least 54-ampere hours. With this, your machine can support one night of sleep.

CPAP units utilized by truck drivers usually require a 30-40 ampere hour- battery for 2 nights. Such batteries often weigh 20 lb.

At a 10 cm water pressure setting, a 2.5 ampere CPAP needs 36 amp-hours in 8 hours. In this case, you need at least 40 amp-hours to support 12 hours usage.

Breaking it down…

To better understand all of these, you should know what ampere hours mean. Ampere Hour, Amp Hour, or AH is the measurement used to represent the battery capacity of a device. In other words, it indicates the amount of energy that a battery can store.

For example, a CPAP battery can store 70 AH. This particular battery is specified at 3.5 amperes. This implies that this battery can continuously supply 3.5 amperes to a load for 20 hours.

When it comes to your CPAP’s power, you may use an ammeter or estimate it using the method below.

  1. Divide your CPAP’s wattage by 12 volts in order to calculate your inverter’s amperage draw.
  2. Next, multiply the amperage draw by the number of hours you need to use your inverter.
  3. Multiply the quotient by 1.5 to get the Reserve Factor (RV).

From this point, remember that a reserve factor of two assures a 64 AH battery. This battery rating is enough for continuous use of your CPAP for 12 hours. A 95 AH battery, on the other hand, can last for 2 nights without recharging. If you sleep 6 hours per night, a 95 AH battery can last for 3 nights.

If you are using an inverter, compute the amperage draw and add 10% to it. For exampl


e, if 2.5 amperes is the quotient of dividing 30 Watts by 12 volts, then 2.5 amperes multiplied by 10% or 0.1 is equal to .25.

In short, once you know the amperage and the voltage of your inverter, you can compute the power that your CPAP needs.

Here is another example.

If the current is 4A and the voltage is 220V, then multiply 4 by 110 to get the wattage. To calculate the power consumption, divide the product or the wattage by 745.7 since 1 HP is equal to 745.7 watts.

traveling on road

Important Things to Know While Traveling With a CPAP

Whether you’re a professional driver or a simple traveler, here are a few important tips to keep in mind.

  • CPAP machines are easy to damage in transit, be careful with them.
  • It’s not a good idea to use oxygen while running a CPAP off of a battery. A spark may cause the oxygen to ignite.
  • Depending on your battery, you can run a CPAP machine off of a battery for up to 8 hours.
  • If you stop using your machine for a day two you’ll be ok but, your apnea will return.
  • Remember to always consult with your doctor or the supplier of your unit to better understand the machines power consumption.

Summing it up…

How many watts does a CPAP use? It’s really going to depend on the specific machine that you (or your doctor) decide is best for you.

While on the road, truck drivers should try and use a normal means of power to power a CPAP machine. Normal can be a bit relative, try and power Your CPAP through and inverter or 12 volt and only utilize a battery back up if you absolutely have to.

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