How to Figure Out the Generator I Need 2 Buy to Run a CPAP Machine All Night

[captainsky]

Hi, everyone,

I joined the Bluetti community today because I have a question or two that needs answering. I recently purchased an EB3A Bluetti generator. It is a 268Wh LiFePO4 battery backup with 600 watts (1200 watts Surge). I think it will do fine for my purposes.

However, I desperately need help selecting an appropriate generator, likely by Bluetti, that will meet my sister’s needs to run her sleep apnea machine (CPAP) should the power go out. She has terrible sleep apnea and would not be able to sleep a wink without her CPAP working.

I do not know the model number of her CPAP machine, but when I googled what CPAP wattage machines use, I received the following statement that confused me: math was never one of my best subjects. It stated the wattage of most CPAP machines is between 30-60 watts. Watts is a unit of power and a function of current (amps) and volts (Watts= amps x volts). If you’re running your CPAP off a battery, you need to know the power demand in ampere-hours. I do not understand this formula.

In my scenario, let us assume that my sister’s CPAP machine uses an average maximum of 60 watts. When it says that number, what does it mean? Does it mean the machine uses 60 watts per hour or 60 watts continuously, like every second it is running? I am unclear and would appreciate any feedback that would elucidate the issue. If you know a great article explaining this question, I am okay with it if nobody is keen on writing it out for me.

I need a generator that can handle a 60-watt draw for 9 hours with at least 20% power remaining. Is the number simply 60 watts multiplied by 9 hours, giving the number 540, with 540 meeting 540 watts? If this were the case, my 600-watt generator would be enough power for her. Is that correct?

Based on the formula above, I do not think it would be that simple. Can someone please tell me how to determine how many watts the generator must be to run the 60-watt CPAP machine for nine hours? Explain it to me like I am five if it can be done.

If you have made it this far, thank you so much for reading my questions. I greatly appreciate any help with my problem, and I appreciate your feedback.

[Emax]

Watts is voltage multiplied by the amps. Electric devices use a certain wattage to run. If you want a quantifiable power figure, one you are likely accustomed too, think of watt hours (wh), or kilowatt hours (kWh). A machine that uses 60 watts to run will use 0.6 kWh in an hour.

So, assume her machine is using about 0.5 kWh for a 8 hour sleep cycle. You will want something with a little more actual capacity as these units do consume power when running and they only discharge down to about 15%. I’d recommend something like the Bluetti AC70 or bigger. The AC180 would have even more of a safety net, but is more expensive.

[Mandp]

Some devices can vary in their power consumption. Where you have a range of that consumption i.e. your machine states 30-60W, always defer to the higher number. The easy calculation is 60W per hour for 10 hours is; 60x10=600Wh. This is perhaps your worst case scenario. As mentioned the AC70 at 786Wh is the smallest Bluetti unit that is equal to or greater in capacity than your power needs.
I also agree, given the need is medical related, a larger buffer would be better i.e. the AC180. The Q I would ask myself is; How much is a life worth?

[BLUETTI]

@captainsky Search for the keyword CPAP on BLUETTI’s website: https://www.bluettipower.com/ and you can learn more about these two models X30 & X60, specifically designed for CPAP.