CPAP machine w/ inverter. How much power?
Hi Folks, A little background. Not new to RVing, but starting to deal with battery issues more, now that I have a week long music festival coming up w/ no hookups. I decided that after last year, n...
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Hi bgrass,
You need to think in "watts". 2 amps X 120 volts = 240 watts.
240 watts divided by 12 volts = 20 amps.
Those numbers assume 100% efficiency. You will never get that. 90% is considered good, so draw may be 22 to 23 amps @ 12 volts.
It is entirely possible that the 2 amps is a maximum draw and that the CPAP uses less. The only way to tell is to plug it into a watt meter. My favorite is a kill-a-watt
watt meter
You need to think in "watts". 2 amps X 120 volts = 240 watts.
240 watts divided by 12 volts = 20 amps.
Those numbers assume 100% efficiency. You will never get that. 90% is considered good, so draw may be 22 to 23 amps @ 12 volts.
It is entirely possible that the 2 amps is a maximum draw and that the CPAP uses less. The only way to tell is to plug it into a watt meter. My favorite is a kill-a-watt
watt meter
bgrasspkr wrote:
I, will be using a cheap Radio Shack 300 W inverter. How much MORE( than the approx 2 amp rating) current will this draw.
I have 2 Group 27's paralleled. If I could go direct w/o inverter I could use it for a week! Are these inverters really that inefficient so as to double or even triple the current draw. Doesn't make sense
