solar power for dry camping & cpap machine

[TxGregory]

***Link Removed******Link Removed***Hello, I recently purchased a 2006 Thor Wanderer 30' travel trailer. I was disappointed that I could only run my cpap machine when the trailer is plugged in. I also dislike rv parks, and I really want to spend my time elsewhere, and preferably not plugged in all the time. I am going to put two 100 W solar panels on top. They come with a mounting kit and a charge controller. I thought about just hooking them up to charge the battery, but that doesn't do much for me, because I still can't run my cpap when I am not plugged in. So I was thinking of connecting them to a second deep cycle battery (I have a place for it up front), then using the second deep cycle battery to power an inverter that I would plug into the 30 amp plug that would normally go to external power. My wife also has a cpap, and we like to spend time on our laptops. I put together a picture of what I was thinking. I need some help from someone proficient in electronics to advise me on this. I don't have a lot of money, and I am not physically able to do crawl around the insides of the trailer reconfiguring things. So I came up with this, hoping that it would not all blow up! I am unsure of the size of inverter I need. I would like to just put a 3000W one on, but they are expensive. The 1000W inverter was much cheaper. Also, I am wondering if I need three panels. I am guessing that 3 panels and a 3000W inverter, on a sunny day, would allow me to run everything just as if I was plugged into power. But I don't want to spend that kind of money if I can avoid it.


Thank you in advance,

[MrWizard]

Many of us (if not all)
Have solar because of the inverter
The inverter is not part of the cost of solar
It's not necessary to have an $800 or $1800 inverter to have solar

A $150 go power psw inverter will power the cpap

You can have a big inverter to power the MW at night then recharge with a generator during the day

People get solar to avoid the generator, whether the inverter is large or small

[pianotuna]

Some suggestions:

go with the grape controller.

drop kick the Bogart and use a Victron monitor.

go to a 2000 watt inverter from Outback or Victron, or else drop down to the Xantrex prowatt line ($347.50) from best converters)

Double the battery bank size and consider going to 12 volt jars if you intend to run 1000 watts via inverter.

Replace the manual transfer switch with male and female plugs.

allen8106 wrote:
For what it's worth I am installing a solar system on my 5ver at about $1,811 in cost.

4 - 130 watt panels used from Craigslist. ($65 ea., total $260)
2 - Crown 240 ah 6v batteries ($135 ea., total $270)
1 - Magnum Energy MMS1012 inverter ($737)
1 - Morningstar TS-45 Charge Controller ($143)
1 - Bogart Engineering TM-2030-RV Battery Monitor ($158)
1 - Morningstar battery temp sensor ($25)
1 - Magnum Energy inverter remote ($47)
1 - GE 60 amp disconnect w/fuses ($21)
1 - Generac 60 amp manual transfer switch ($100)
1 - 500amp shunt ($34)
1 - 200 amp DC fuse ($16)

So far I have installed the batteries and the battery monitor. I have purchased everything else and am just formulating my install plan and panel locations. I am fabricating my own panel mounts, I have developed my own wiring schematic and am doing all the install myself.

I expect to be able to run everything except the microwave and the AC without ever running a generator or being hooked up to shore power, my wife also uses a CPAP.

So why all this. To show you that a good solar system install can be done for considerably less than you think and to let you know that what you wish to run in your rig can be done within reason. You'll never run the AC on solar and you'll not likely run the microwave unless you have a really big battery bank and inverter but should be able to run everything else.

[allen8106]

For what it's worth I am installing a solar system on my 5ver at about $1,712 in cost.

4 - 130 watt panels used from Craigslist. ($65 ea., total $260)
2 - Crown 240 ah 6v batteries ($135 ea., total $270)
1 - Magnum Energy MMS1012 inverter ($737)
1 - Morningstar TS-45 Charge Controller ($143)
1 - Bogart Engineering TM-2030-RV Battery Monitor ($158)
1 - Morningstar battery temp sensor ($25)
1 - Magnum Energy inverter remote ($47)
1 - GE 60 amp disconnect w/fuses ($21)
1 - 500amp shunt ($34)
1 - 200 amp DC fuse ($16)

So far I have installed the batteries and the battery monitor. I have purchased everything else and am just formulating my install plan and panel locations. I am fabricating my own panel mounts, I have developed my own wiring schematic and am doing all the install myself.

I expect to be able to run everything except the microwave and the AC without ever running a generator or being hooked up to shore power, my wife also uses a CPAP.

So why all this. To show you that a good solar system install can be done for considerably less than you think and to let you know that what you wish to run in your rig can be done within reason. You'll never run the AC on solar and you'll not likely run the microwave unless you have a really big battery bank and inverter but should be able to run everything else.

[Sam_Spade]

TxGregory wrote:

I have no DC outlets anywhere in my 30' thor wanderer that I can find.

Sorry. I ASSumed.

Mine has at least one in every living area section.
The one in the bedroom is high on the wall right beside the TV cable outlet.

In order to do this "right" you are going to have to have an electrician do something. Either run a 12 V outlet OR split a bedroom outlet off from the main AC feed OR install a separate new AC outlet for the inverter.

[red31]

TxGregory wrote:
I would need to generate around 3600 watts to power my 30 am cord/plug if I was to mimic what the power company provides using my solar panels. So my 200 or 300 watts of solar power is only going to give me around 2 or 3 amps of current

right, 2 amps @ 120v is 240 watts. Don't let others confuse you by stating amps without an associated voltage. Amps is nothing without voltage.

[SoundGuy]

TxGregory wrote:
I am ashamed to admit that I took two semesters of electronics in college, but I do not remember anything from them! I think I now see that I would need to generate around 3600 watts to power my 30 am cord/plug if I was to mimic what the power company provides using my solar panels. So my 200 or 300 watts of solar power is only going to give me around 2 or 3 amps of current, unless I save it up in the batteries.

Evidently you have forgotten "everything" ... 200 to 300 watts of solar in full sun will generate a lot more than just 2 to 3 amps @ 12 vdc. Seems you're not differentiating between 120 vac and 12 vdc power, also evidenced by your earlier comment that you were "devastated" to discover that your 120 vac duplex outlets aren't powered unless the trailer is plugged into shore power. :R I'll stick to my original recommendation - find someone to help you who understands electrical systems, 'cause clearly you don't. 😉

[pianotuna]

Hi TxG,

Here is a simple flow chart:

Solar-->battery bank-->inverter-->RV

In June from 256 watts of solar I get up to 17 amps (at solar noon). The daily harvest is about 100 amp-hours (at 12 volts), so about 1200 watt-hours per 24 hours. On December 21, the harvest is 17 amp-hours or about 204 watt-hours.

An 800 watt inverter running "flat out" may draw about 80 amps of current @ 12 volts.

What is needed to set up a system is an energy audit. Then we can help you design a whiz bang system that won't cost an arm, a leg and your first born child.

The best way to do an energy audit is by direct measurement. To do that I'd invest in a kill-a-watt meter and run the RV from a 15 amp shore power circuit for one week. The meter will show the total energy use.

TxGregory wrote:
So my 200 or 300 watts of solar power is only going to give me around 2 or 3 amps of current, unless I save it up in the batteries. But panel/batteries they should power my cpap and laptops and I would only need a 800 watt inverter for that. If I want A/C I will need a generator. I can't tolerate the noise very long due to my chronic medical problems.

[TxGregory]

Sam Spade wrote:

TxGregory wrote:
But I don't want to spend that kind of money if I can avoid it.

Not sure about the cost of this but I think you would be better off in the long run to get CPAP machines that run directly off 12 V and then just increase your battery capacity if needed.

Or check the wattage of your present machines and get a small inverter to power just IT from an existing 12 V outlet.

Feeding an inverter into the whole RV is probably not a good idea; too easy to overload it.

Thanks for the reply Sam,
I have no DC outlets anywhere in my 30' thor wanderer that I can find. I have lots of nice AC outlets just where I need them. And those pretty little AC outlets only work when the trailer is plugged into a 30 power source. Getting a DC plug for my CPAP is pretty easy to do, but it won't help me unless I pay an electrician to run DC outlets.

[TxGregory]

12thgenusa wrote:
First of all, welcome to the forum.

You can probably do as others have suggested and power the CPAP off 12v if you have a 12v receptacle near by and can adapt the machine to take 12v directly. However, that doesn't help you with powering laptops. Your picture doesn't come through BTW.

If powering those items is all you really want and not "everything", two 100w panels, two batteries connected in parallel and a 1000w or even a 600w PSW inverter will do nicely. Connecting the shore power cord to the inverter directly is a simple way to do it, but if you do it that way you must remember several things.

1. Make sure your converter is unplugged or breaker off or it will deplete your battery bank quickly. If your converter breaker also powers some of the outlets as mine did you will have to separate the wires and add another breaker or tripping the breaker for the converter will also turn off the outlets you probably want to use.

2. Make sure the fridge is set to gas not auto or the inverter will try to power the heat element.

3. Make sure the water heater is set to gas for the same reason.

4. Don't even try to turn on the air conditioner.

5. Remember that even though all the outlets are live, you cannot power "everything".

I have my inverter wired to "whole house" through a manual transfer switch that simultaneously interrupts the circuits for the converter, fridge, water heater and air conditioner so I don't have to remember to turn things off or back on.

I run a 2k PSW inverter that I leave on at night to power a CPAP. With the humidifier on it takes about 24Ah per night including inverter losses.

Thank you for your reply 12Gen,
I tried to edit my original post to get my google doc images to show. I can't see images in anyone's posts. I am not proficient enough in electronics to do the things you suggest. And I really can't afford to pay an electrician. I had no idea running my cpap in the travel trailer was going to be so difficult. I was so happy when I saw those AC outlets with a little table to put my machine on!

[TxGregory]

time2roll wrote:
Really need six+ batteries to properly drive a 3000 watt inverter anywhere near the max.

I think 300 watts would be fine for what you describe as your camping needs. Maybe 200 to 400 watts solar.

If you want microwave, electric coffee, toaster, hair dryer etc you are looking at 2000 watt inverter, four+ batteries and 500+ watts solar. Or just add a Honda 2000 to the above.

If you want air conditioning and the rest you need 4000 watt inverter, 3000 watts solar, and a large lithium battery. All running at 24 or 48 volts. Or add a second Honda 2000 to the above.

***Link Removed***

Dear Time2Roll,
I am ashamed to admit that I took two semesters of electronics in college, but I do not remember anything from them! I think I now see that I would need to generate around 3600 watts to power my 30 am cord/plug if I was to mimic what the power company provides using my solar panels. So my 200 or 300 watts of solar power is only going to give me around 2 or 3 amps of current, unless I save it up in the batteries. But panel/batteries they should power my cpap and laptops and I would only need a 800 watt inverter for that. If I want A/C I will need a generator. I can't tolerate the noise very long due to my chronic medical problems.

Thanks again for your help.

[TxGregory]

MEXICOWANDERER wrote:
Examine the plug in brick carefully. By law the brick must display the power voltage range admitted from the AC plug in inlet to the brick (this cord is usually disconnectable just like a laptop power brick cord)

And then the brick's info with continue on and then list the output voltage and amperage potential of the brick. Aha! This is what you are after. Write down the voltage (12 volts)? and write down the amperage (5 amps)?

Does the brick say 12 volts and 5 amps (very common)?

If yes, you can purchase a power cord that plugs into a cigarette lighter socket, then purchase a long extension (I have encountered ads for 12 feet) cigarette light plus an socket extension cords.

This is a far more practical way than using a PURE SINE WAVE inverter that wastes power converting 10 volts to 120 volts AC then back to 12 volts. The power waste going to inverter is expensive and is sort of nuts...if tour CPAP is indeed 12 volts.

But with a battery conversion the CPAP must be unplugged from the cigarette lighter before starting the engine.

Dear Mexico Wanderer. I also did some wandering in Mexico in my younger years, Yucatan and Oaxaca. Drove my van down there and brought back a load of zapotec rugs and black pottery from Dona Maria.

Regarding my cpap and laptops. The problem I have is that my Thor Wanderer does not have a DC plug inside of it. I have searched and searched. I looked near the TV hoping to find it there, but no suerte! I have lots of AC outlets, and they are in all the right places. I have them on either side of the queen sized bed with nice little table tops to put your CPAP machine. I was devastated the first time I dry camped and the AC outlets had no power (they work just fine when you are plugged into electrical power). Paying an electrician to install USB outlets is an option I suppose, but money is very scarce for me so I am trying to do things on the cheap!

[JC2]

TxGregory wrote:
***Link Removed***Hello, I recently purchased a 2006 Thor Wanderer 30' travel trailer. I was disappointed that I could only run my cpap machine when the trailer is plugged in. I also dislike rv parks, and I really want to spend my time elsewhere, and preferably not plugged in all the time. I am going to put two 100 W solar panels on top. They come with a mounting kit and a charge controller. I thought about just hooking them up to charge the battery, but that doesn't do much for me, because I still can't run my cpap when I am not plugged in. So I was thinking of connecting them to a second deep cycle battery (I have a place for it up front), then using the second deep cycle battery to power an inverter that I would plug into the 30 amp plug that would normally go to external power. My wife also has a cpap, and we like to spend time on our laptops. I put together a picture of what I was thinking. I need some help from someone proficient in electronics to advise me on this. I don't have a lot of money, and I am not physically able to do crawl around the insides of the trailer reconfiguring things. So I came up with this, hoping that it would not all blow up! I am unsure of the size of inverter I need. I would like to just put a 3000W one on, but they are expensive. The 1000W inverter was much cheaper. Also, I am wondering if I need three panels. I am guessing that 3 panels and a 3000W inverter, on a sunny day, would allow me to run everything just as if I was plugged into power. But I don't want to spend that kind of money if I can avoid it.


Thank you in advance,

Here is an excellent link for purchasing invertors. Very reasonable in price and will answer your questions when calling. We purchased a 1000w pure sine wave invertor to use for our residential fridge when we replaced the junk Dometic rv fridge.

http://www.donrowe.com/

[pnichols]

MEXICOWANDERER wrote:
Never in many decades heard the complaint "Bought too many panels" nor "battery bank is too large". Engine starting battery is too powerful. Points to remember well.

Mex should have worded it differently, as such: "You can never have too many solar panels, or too many batteries, or too big of a starting battery ... only more than you can afford or fit". 😉

(As for us,, we have no solar at all on the RV or at the residence - we carry both a large and small generator in the RV and we won't live at our residence long enough in the future to realize anywhere near a payback. Ya gotta be careful which bandwagon you jump on.)

[12thgenusa]

MEXICOWANDERER wrote:
Never in many decades heard the complaint "Bought too many panels" nor "battery bank is too large". Engine starting battery is too powerful. Points to remember well.

Yeah, I would like to have a $500,000 EarthRoamer too, but . . .:)

[MEXICOWANDERER]

For 30 years I have never found where a person advised a certain size solar setup that ended up matching the user's needs. The last solar trailer I did the owner wailed the air blue with expletives when I forced him to purchase a 40 amp MPPT controller and ran 6AWG wire to the batteries. Upset ilwas not the word. 2 years later he cornered me in Home Depot. Wuuwee apologetic "I added six panels". I got a free Sushi lunch. This point is well worth remembering.

Never in many decades heard the complaint "Bought too many panels" nor "battery bank is too large". Engine starting battery is too powerful. Points to remember well.