Puritan Bennett GoodKnight 420 Series 12 Volt DC Power Cord (connects CPAP to cigarette lighter socket)

CPAP Video & FAQ

Frequently Asked Questions (FAQs)

What type of power does my CPAP need?

Most CPAP, APAP and BiLevel machines today are designed to operate on both AC and DC voltage. In the United States, the AC current from a wall outlet is 110 volts. Overseas, the AC current is usually 220 or 240 volt. Most batteries produce 12 volt DC current.

We include information about the power needs and capacities on the CPAP.com pages our products. Please see the "POWER" tab on any machine product page for this information. You can also see a summary of the voltage range and whether it is DC capable on our Compare Charts.

Here is a video explaining differences in power cords and power supplies of various CPAP machines:

Will my CPAP operate on DC / battery power?

All CPAPs will operate on DC power with the use of an Inverter to change the current from DC to AC before it reaches the machine. However, many will operate on DC power without the need for an inverter, just a power cord that plugs into the CPAP and ends in a cigarette lighter plug.

Inverters do require a lot of power. If you need to use an inverter to run your machine on battery power, the inverter will probably take about half the life off the battery.

To determine if your CPAP will operate without an inverter, look for a DC outlet on the machine, either at the back or on the side, with a single opening directly in the center. It should be labeled "DC POWER" or similar term. You can also review our Compare Charts to see if your machine has a optional DC cable option.

Here is a video describing different DC cable and battery options for various machines:

Will my CPAP operate overseas?

An adapter may be required to plug a US power cord into a wall outlet in a foreign country. CPAP.com sells an assortment pack of World Traveler Power Adapter Plugs, which allow CPAP machines to plug into different types of wall sockets found in different countries.
All the models CPAP.com sell contain power converters that enable the machine to operate on any AC current from 100 to 240 volts without any adjustment.

How do I use a battery to operate my CPAP?

All machines can connect to DC power. Some machines are configured to operate on DC Power and have a DC power outlet. Other machines require AC power and will need an Inverter that turns DC power to AC power.

Having the proper equipment is the biggest key to successfully operating the machine from a battery. For example, if your machine does have a DC outlet and you want to run your machine from a marine battery, be sure to get the correct DC cable for the machine, as well as an adapter cable with alligator clips that fits over the cigarette lighter plug.

CPAP.com sells complete battery kits with everything you need for many machines including the correct cables for those machines and batteries. If you have questions about the specific power needs of your machine, review the 'Power' tab found on the machine's product page, or give us a call at 1-800-356-5221.

What type of battery should I use?

For longer battery use, we suggest using a deep-cycle marine battery to power the machine. A deep-cycle marine battery is heavier than the ordinary battery, but it has many advantages. The battery is easily found at auto shops and it provides power to the machine for an extended period of time. For example, a CPAP machine set at 10 cm H20 and charged on a deep-cycle marine battery will usually last three nights before it needs to be recharged.

There are small, portable battery packs that will operate a CPAP set at 10cm for at least one night, or about eight hours. CPAP.com sells full Battery Kits that come with everything needed to run your machine off battery power including the correct cables needed for your machine and a battery. You can find the battery kit for your machine Here. On each battery kit page, you can input your machine and pressure setting to see an estimate battery life for your machine.

Some machines have batteries created to be used specifically with them only. Here are some of the machines we carry with integrated or specialized battery options:

Transcend EZEX miniCPAP™ Machine
Z1 Travel CPAP Machine
Transcend Auto miniCPAP™ Machine with EZEX
Z1 Auto Travel CPAP Machine

How do I prepare for power outages with CPAP?

There are a lot of back up battery choices out there that can give you peace of mind in case of a power outage. The Transcend Travel CPAP Machine has Battery Options available that can set up as a fail-over, back up battery. Review the 'POWER' Tab on the machine page.

CPAP.com sells Battery Packs to accompany your machine if an integrated battery is not available. Visit CPAPtalk for more advice specific to your needs, or view this past thread on the topic here.