Power Supply for Puritan Bennett 420G, 420S, 420SP and 420E CPAP

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:

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.