Battery bank size

[Max Freedom]

I recently went camping over thanksgiving..... The weather was cool in the evenings 40 degrees f... I recently had to get a cpap which I run at night five amps per hour times 8 equals 40 amp hours... I also had to run my heater over night heating to 60 degrees f.... I have a 200 ah battery bank, 12 volt, 2 batteries.... By the morning the batteries are dead..... I've replaced my batteries, checked my converter....... Checked my inverter..... Rewired my batteries..... Checked my 180 volt solar panel system flat mounted..... After all that my batteries were still dead by morning.... How much electricity does a furnace use? Do I need to add another battery? Does anyone out there use a cpap and heater what is your experience? I am concerned because I will be going to Yellowstone this summer where 30 degrees f at night is not unheard of. Any suggestion will be appreciated.

[firedoc]

Does your cpap have a heater for humidification? If so I bet it uses more power than that. But even so you will have phantom power drains from things like refrig controls, propane alarm, radio, etc.

I have a cpap and can use it on the rare instance we dry camp but we have 4 6v batteries and they are fully charged at bed time. No problems.

[rgreen45]

I can't figure why the convertor can't keep up. By mentioning that you checked the convertor, I assume you're plugged in, right?

[clyon51]

If you were plugged into shore, your converter must not be working. Check for 120v on the converter outlet. Then check coach batteries while on shore. You should see at least 13.2v and upwards of 14.3v if working properly. If not, check the fuses on the converter. If that checks out, then I can only conclude the converter has failed.

As far as dry camping (no shore) with that heated CPAP using 120v via inverter is probably what's killing you, of course depending what other 120v items you use and how long.

I have about 230AH and can go at least 48 hours. The wife uses a CPAP at least 8 hours a day. However, I wired it for 12v (just bought the 12v cord). This disables the heater, but she says it isn't necessary. In remodling, I replaced the TVs with 12v LEDs and all lights with LEDs and have no solar and no use for an inverter. It's all about consumption and AH.

[LandKinaMoho]

Solar power should be 3 x 100w high efficency panels minimum. 2000w inverter. Batteries 4x 6volt to get a good basic result. Shore power issue could be routine maintenance required of the house set up.

[Ray,IN]

Your answer to rgreen45 will help immensely. Were you plugged into shore power or operating off your house batteries? Without your answers we cannot offer sound advice.

[Dunner]

I just found out today, that one of the two outlets in the basement compartment, just in front of my entrance door, is controlled by the GFI by my lavatory sink. Didn't check what controlled the other one that my converter plugs into.

[clyon51]

I would think any outlet accessable on the outside of the coach must/should be protected by a GFI. I've never varified this on my coach, better go check I guess.

[Dunner]

Had me wondering what went wrong. The converter outlet is a single and the one on the other side that I use for my compressor is a duplex. This site has taught me to check the GFI outlets first. Musta bumped the one in the lavatory while hanging a clean towel. At first, I thought the generator had to be running for that outlet.

[KD4UPL]

If you are dry camping with no electricity the converter will contribute nothing. Most furnace and CPAP usage will be at night so the solar will contribute nothing. A 200 Ah battery bank is really only 100Ah to 160Ah of usable capacity if you don't want to completely flatten your batteries. jThe furnace is probably 6 amps for, say 6 hours a night, that's 36 AH + 40AH for the CPAP + whatever else you were using must be too much. It sounds like you need more battery capacity.
However, I'm assuming a lot since I don't know if you were on grid or off.

[RamblingRV]

I'm still a newbie, but if your cpap is like my mom's, it runs on AC, not DC. Therefore your DC would be going thru your inverter first. At low wattage, inverters can be terribly inefficient, particularly if it is a large inverter running a small load. So is your cpap AC or dc? How big is your inverter? (Assuming you we're dry camping in this post).

RRV

[Max Freedom]

Inverter is 400 watts.... And I am dry camping...

[dagmandt]

Are you charging your batteries full? 14.8v until the battery rests at 12.8v without load after a couple hours. Do you have any parasitic loads?

[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...