My last question was not posed correctly especially on a DIY forum and my apologies. Hopefully this will be much better
I am trying to power a CPAP machine while away from utility power. This system is going to run the CPAP and possibly charge a cell phone once in awhile so if it grows I may double the batteries to increase the run time but that's it.
I plan on solar charging this most of the time but would like to use a wall outlet when available
One thing I am looking at is building a battery pack using Panasonic NCR18650B cells 3400mah in a 7S 5P configuration which I estimate about 430 Wh at 24V, a 60A 1400W BMS, 12V dc output and a 5V 2.4A or 3A USB output
The CPAP is rated on the wall adapter at 12V 5A and although I don't currently have a Kill-A-Watt I found someone online who has the same unit and measured his at 8A starting current and about .4 amp the rest of the night and used 40Wh. I will be getting a dc plug for this so the draw should go down.
Would this be better to just build as a 12V system and not worry about the converter, since cables will be in inches I wouldn't think there would be much loss either way.
My biggest concern for this is reliability
The cost is estimated at @ $250 to $300
Bob
I am trying to power a CPAP machine while away from utility power. This system is going to run the CPAP and possibly charge a cell phone once in awhile so if it grows I may double the batteries to increase the run time but that's it.
I plan on solar charging this most of the time but would like to use a wall outlet when available
One thing I am looking at is building a battery pack using Panasonic NCR18650B cells 3400mah in a 7S 5P configuration which I estimate about 430 Wh at 24V, a 60A 1400W BMS, 12V dc output and a 5V 2.4A or 3A USB output
The CPAP is rated on the wall adapter at 12V 5A and although I don't currently have a Kill-A-Watt I found someone online who has the same unit and measured his at 8A starting current and about .4 amp the rest of the night and used 40Wh. I will be getting a dc plug for this so the draw should go down.
Would this be better to just build as a 12V system and not worry about the converter, since cables will be in inches I wouldn't think there would be much loss either way.
My biggest concern for this is reliability
The cost is estimated at @ $250 to $300
Bob