Alec, thanks for posting the life support test for Snoopy. I quite enjoyed seeing actual test data. Your results of axial vs. radial fans mirrored my results and my conclusions were the same; i.e., radial fans are the way to go. Have you done any test or calcs to see how long a 0.36 amp current load will take to burn your backup batteries? My guess is that at this current, you would not make 72 hours. IF they don you may have to find a radial fan that draws less current.
I note from your test data that your CO2 readings look high. Atmosphric air has about 300-400 ppm of CO2. As there are 10,000 ppm per 1%, this translates to 0.03% to 0.04% . At the point you initiated each test, you were seeing 0.385, 0.25 and 0.27% for the base case, radial fan
and axial fans, respectively or in terms of ppm, 3800, 2000 and 2700. This could be becuase your CO2 sensor is out of calibration or there was a lot of exhalation of CO2 in the boat prior to the start of each test. When I did my in the garage life support test, I found that it was necessary to use my air compressor with a nozzle to purge the cabin to get the CO2 level back to normal air for the start of each test. If the CO2 sensor readings are correct, then with the axial fan, you reached the ABS maximum allowed CO2 level of 5000 ppm (0.5%) reading at 4 minutes. If the CO2 sensor had a 1600-1800 ppm bias error, then the axial fan would have also kept the cabin below the 5000 ppm for the duration of the test.
Thanks again for posting.
Cheers Cliff