Can a battery and inverter run a home oxygen concentrator overnight in an RV?

Answered by RV Parts Giant · Upland, CA · September 29, 2026

Short answer: Often yes, but the size comes from your concentrator's own label, not a rule of thumb. Multiply its rated watts by the hours you need, add inverter losses and the rest of the rig, and size a lithium bank so you use about 80 percent of it, through a pure sine inverter. Plan any backup for equipment you depend on with your supplier and clinician.

This is a power-sizing answer, not medical advice, and we are not qualified to give any. Confirm what your concentrator needs with its maker or the supplier who provided it, and if it is life sustaining, plan your backup with them and your clinician. What we can do is the arithmetic and the wiring.

Start from the label

The concentrator's rating is printed on the unit or in its manual. Volts times amps gives watts. Two things to know about that number:

It is a maximum, not an average. The only way to learn your real average is to measure it.
From a 12 volt battery the current is about ten times the AC current. 120 watts from the wall is roughly 10 amps from a 12 volt bank, which is why the DC cable is so much heavier.

The sizing method

Use your own numbers in place of these example ones:

Nightly energy. Rated watts times hours. 120 watts for 8 hours is 960 watt-hours.
Inverter loss. At 90 percent efficiency the battery supplies about 1,067 watt-hours.
Amp-hours. Divide by 12.8 volts: about 83 amp-hours.
The rest of the rig. Fridge, lights, fans and pump. Add them.
Headroom. Plan to use about 80 percent of a lithium bank, so divide the total by 0.8.
The recharge. Whatever you use overnight has to go back in the next day from solar, the alternator or shore power.

A home concentrator usually draws far more than a CPAP, so expect the bank to be large. Run the numbers before you buy anything.

The inverter

Use a pure sine inverter. Many equipment makers specify it, and motors and power supplies run hotter on modified sine. Every inverter we stock is pure sine, from the Phoenix range to the MultiPlus-II inverter-charger, which also charges the bank on shore power.

Count the inverter's idle draw too. Victron's small Phoenix VE.Direct models use about 4.2 watts (12/250) to 6 watts (12/500) at zero load. Do not use ECO mode for equipment you rely on: it sleeps until it sees a load, and a steady low draw may not wake it.

Fusing and monitoring

Fuse the inverter feed at the battery, sized to protect the cable. Then fit a shunt monitor. Lithium voltage stays almost flat until the battery is nearly empty, so a voltmeter will not warn you at 2 a.m. A SmartShunt counts every amp and shows the concentrator's real draw in the app, which turns the estimate above into your own figure after one night.

We sell the power system only: inverters, batteries, fuses and monitors. We do not sell oxygen equipment or any medical cord or adapter. Send us the label and your nights off hookups and we will size the bank. We ship from Upland, California.