Johney: "My 60 amp charger is too much for a blah blah 100 A/H......" Keep in mind that if you add 2 100 A/H batteries the charge will be split between them so each will get a max of 30 amps
Mike, it's important to understand that the bulk of a CPAP power consumption profile is in the temperature control and humidifier. If the user can do with minimal hose temperature and humidity control, the power consumption drops dramatically (70% less). Many boondockers (me included) run their CPAP's with a low temperature setting and no humidifier. Dry nose/mouth can be a problem for some, but not me. As always, YMMV.
Just an FYI, you can usually find DC-DC power supplies on Amazon for most CPAP machines. I have a ResMed, and untill I upgraded my system I was able to run my machine with humidifier all night on a 200-AH AGM. The voltage drop was about .3 volts.
Hello Mike, I would be careful with regard to telling people with CPAP's (and in my case a non-invasive ventilator) that they have 12.6 VDC X 100 Amp hours available from a100 Amp-hour liFePO4 battery. . First of all, as you know, there is the knee in the voltage vs. state of charge curve: The output voltage from the battery is going to drop off very sharply at around 10% S.O.C. resulting in no usable 12 VDC power to the CPAP. Unless you have a Coulomb counting battery monitor, I would advise to not plan on going any lower than 20% S.O.C. by the following morning (after CPAP use all night). Second, as you have indicated in previous articles, unless one has a charger with a LiFePO4 compatible charging profile, the "fully charged" LiFePO4 battery may be at only 80% S.O.C. Instead of having 100 Amp-hours usable, there may be realistically only 60 Amp hours usable (80%-20% X 100 Amp-hours).
As an extra measure of safety, to provide power to my non-invasive ventilator, I place my Jackery Explorer 500 portable lithium ion power source (500 Watt-hour capacity) in series with the connection from my house battery bank-sourced 12 VDC.
Johney: "My 60 amp charger is too much for a blah blah 100 A/H......" Keep in mind that if you add 2 100 A/H batteries the charge will be split between them so each will get a max of 30 amps
Mike, it's important to understand that the bulk of a CPAP power consumption profile is in the temperature control and humidifier. If the user can do with minimal hose temperature and humidity control, the power consumption drops dramatically (70% less). Many boondockers (me included) run their CPAP's with a low temperature setting and no humidifier. Dry nose/mouth can be a problem for some, but not me. As always, YMMV.
Just an FYI, you can usually find DC-DC power supplies on Amazon for most CPAP machines. I have a ResMed, and untill I upgraded my system I was able to run my machine with humidifier all night on a 200-AH AGM. The voltage drop was about .3 volts.
Hello Mike, I would be careful with regard to telling people with CPAP's (and in my case a non-invasive ventilator) that they have 12.6 VDC X 100 Amp hours available from a100 Amp-hour liFePO4 battery. . First of all, as you know, there is the knee in the voltage vs. state of charge curve: The output voltage from the battery is going to drop off very sharply at around 10% S.O.C. resulting in no usable 12 VDC power to the CPAP. Unless you have a Coulomb counting battery monitor, I would advise to not plan on going any lower than 20% S.O.C. by the following morning (after CPAP use all night). Second, as you have indicated in previous articles, unless one has a charger with a LiFePO4 compatible charging profile, the "fully charged" LiFePO4 battery may be at only 80% S.O.C. Instead of having 100 Amp-hours usable, there may be realistically only 60 Amp hours usable (80%-20% X 100 Amp-hours).
As an extra measure of safety, to provide power to my non-invasive ventilator, I place my Jackery Explorer 500 portable lithium ion power source (500 Watt-hour capacity) in series with the connection from my house battery bank-sourced 12 VDC.