Originally Posted by Max Freedom
I have some parasitic loads. I fully charges the battery bank..... With the nights use lights, use of furnace, and cpap use other parasitic loads the batteries are drained by morning...
Your problem is AHs (Amp Hours). I suspect you replaced your batteries with two 12v. If they are just starting batteries, that is your problem. If they are "marine" batteries, that is better, but far from optimal. The minimum you need is two 6v true deep cycle "Golf Cart" batteries. 2 of these are 240AH. Even if you bought 12v true deep cycle, they still aren't enough, apparently. The 6v may not be either if your AH useage is just too great.
The first problem I see is the use of an inverter to power the CPAP, especially if you insist on using the incorporated heater. Not that you don't have a 120v only CPAP, but all I have ever seen are 12v. They just come with a 120v plug and have a 120/12v converter incorporated into the cord. If you follow the plug to the plug on the CPAP, you should see a small 12v wire that plugs into the CPAP, then another heavier cord going to the 120v heater portion.
If you check the model and mfg then search for "cpap supplies", you can make your way to finding a 12v cords and option battery packs. Most CPAPs are designed so you can travel with them. I got a 12v cord for the wifes and just tied it into a 12v circuit. She fills the humidifier with water and does not need the 120v heater.
LED lights will save you 90% over incandesent. A 12v LED TV will save the same over a 120v using an inverter. It's all about conserving when dry camping. We have two 6v GC batteries and go 48 hrs without the genny. That's running CPAP 8hrs a day, fantastic vent 8hrs, TV 3-6 hrs, lights as needed and the furnace at night.