Solar's purpose

[MichaelInNM]

Super confused here and I'd appreciate someone setting me straight.

We NEED to run 2 CPAPs, an O2 concentrator, and ideally AC through the night to sleep. I was under the impression that with several batteries (I was told 8) this would be fine running on house batteries for 1 night, and then that I could have a solar setup on the roof that would recharge the batteries the next day. Therefore while boondocking I wouldn't need to run my generator at night and make all of my neighbors want to slash my tires at 2am.

Spoke to a Newmar / Tiffin dealer here about this when looking at a coach we may buy and he said it's not possible. If not hooked into shore power you must use generator to run my required accoutrements. Said solar is only to trickle charge chassis batteries and only would charge a little bit- roughly the parasitic draw while parked and then some.

So- what's true? Am I going to end up being the guy that has to park at the far end of the park, or can I get what I need while leaving neighbors with the sweet sound of silence?

Any input is appreciated.

[geordi]

Unless you want to install somewhere around $15,000 in lithium batteries, running the air conditioner overnight is just not going to happen. That said, the dealer guy is a moron (not unusual) and doesn't know what he's talking about - which is not uncommon at all either.

I can't comment about the other devices without more information - they should each have a sticker or label near the power cord that says how much power they need in two of these three things: Voltage, amperage, watts. Ultimately you need to know the wattage to know how long these things can run on X amount of power from an inverter and batteries, so let's start there.

But solar is used to charge batteries, and how much solar you need is a function of how much power you need PLUS how much sunlight and time you will expect to have.

Figure all your calculations on having just 5 hours of sunlight per day, and size the system accordingly. Solar elements are pretty standard size, so a panel that produces 350 watts is going to be about 40"x80" so you need to know that you have enough roof space for that - times the number of panels you want.

[jcussen]

With a big enough battery bank and big enough solar, you could probably run your cpap's and concentrator overnight without using generator. Running a roof air overnight as well, would require a massive system.

[MichaelInNM]

Thank you both. So I know I can't be the only one that's using a CPAP and likes their A/C. Is running the generator just not as big of a problem in a class A as I've heard other people complain about? Would YOU be my neighbor?

[Mr Lars]

Although we don’t boondock ‘off-grid’, part of me ask’s if need A/C, most of your neighbors do to?
You mention ‘in a park’, are there ‘parks’ that have no hook-ups? If there are, I don’t know what call those, but an open field, but that’s me.
Good luck, I wouldn’t mind at all being your neighbor, your A/C don’t bother me, mine will be running also.

[arcaguy]

You can run pretty much anything you want to on solar is you have enough solar panels and batteries, and that is where the rub comes in, it's hard to put that many panels or that many batteries in a motor home. Lithium (Lithium Iron Phosphate (LiFePo)) batteries are about $1,000 each. Solar panels are about $300 to $500 depending on size plus a probably another $2,000 to $3,000 or more for other control stuff that I won't go into right now. The $15,000 number was probably about right but you still probably won't be able to run your A/C all night. The amount of solar panels is limited by how much roof space you have, and possibly the number of portable panels you want to deploy on the ground, but there is a limit. My question is "Do you need to run your A/C all night?" Where are you going to be that it doesn't get down to 70 or so at night unless you're in the desert in middle of the summer. This not your house and an RV will lose heat much faster than a house. I live in Michigan and even when it's in the 90's during the day it's a rare night I can't run a fan and cool my bedroom off enough to sleep comfortably. My philosophy is if it's too hot I go up in latitude or altitude, if it's too cold I do the opposite. Unless you have to be someplace for work or some other reason I don't see any reason you can't be someplace where A/C is not needed at night. Just my thinking, which my wife tells me is always confused to so take it for what it's worth.

[Isaac-1]

I have to somewhat disagree with the above comments, it can be done, people are doing it, but you are not going to find many factory setups that offer this yet. And the factory ones that are out there are mostly on smaller class B and B+ RV's with their smaller interior volume, by using lithium ion batteries, combined with solar panels, and auto-starting engine driven high output alternators, etc. Even then most don't have enough capacity to run the roof mounted air conditioner for more than 3-4 hours. Take a look at

https://www.youtube.com/watch?v=xyj9vlfaRY4

( I am not advocating this model, just pointing out what is now available on the market with lithium ion batteries, larger inverter for its size that will power the roof top air conditioner, etc.).


As to the cost of doing it yourself, it can be done and the price is dropping all the time, cost to install large (500-1000 watt) RV rooftop solar has probably dropped 30-40% in the last 5 years, and had dropped that much or more in the 5 years before that, etc. In other words today a DIY'er can buy 500 watts worth of solar for what 50-75 watts would have cost 15 years ago. ( bought a 55 watt solar panel in 2005 for $325 which was a smoking deal at the time on a blemished factory second panel, earlier today I just saw an add on another forum for brand new 400 watt panels for $220 each. Prices are also falling on lithium ion batteries, not only are they falling but the newer batteries tend to have longer service life and better performance than the old ones.


I was running the numbers to do a lithium ion conversion on my 28 ft class A coach that would support 7-8 hours of a single air conditioner running the other day, and I came up with a ballpark number of around $7,000 as a DIY project, though in my case I already have a 2,000 watt pure sine wave inverter. Ballpark figure to run an air conditioner you will need 100AH of lithium ion battery per hour or run time, with some creative shopping today, one can buy an off brand 200AH 12v battery for about $1,000 see https://smile.amazon.com/Napok-Lifep...dp/B07ZTL6KWT/ for quick first one I found reference. So 4x$1,000= $4000 for 8 hours battery supported air conditioner actual run time may be longer depending on compressor cycle. $1,2500 for a 3,000 watt pure sinewave inverter https://smile.amazon.com/Victron-Mul...dp/B0054PRVAS/ add in $500 for a good MPPT solar charge controller, and how ever many $220 400 watt panels you can pack onto the roof (probably in the 1,200 watt ballpark), and there you have it, add in another $1,000 for wiring, mounting brackets, etc. Again I am not advocating this particular models, they are just representative, there are also other components you may want like a DC-DC charger to let the system charge from your engine while you are driving down the road, etc.

[Dutch Star Don]

Pretty simple answer........if you have 6-8 batteries, fully charged by the generator, before you go to bed (run at dinner time for two hours), you'll have enough power to operate the CPAP and the O2 Generator.

Running the A/C is out of the question. Yes it can be done, with thousands of dollars in equipment, but it would be far from cost effective.

If you're staying where there is no power and hot enough that everyone else is running their A/C units then it won't be a big deal to run your generator all night.

With all that said, you need to do the math and see if running your generator all night is cheaper than paying for a campground with power. Adding solar to charge batteries, and/or changing to better batteries, really requires that you take a good look at how you'll use your RV.

In our situation, the longest we boondock, is 5 days, once a year at Yosemite. I'm not going to spend a fortune to install enough solar to power the coach for those five days a year. It's sooooo much cheaper to run the generator for two hours twice a day.

Others may live in the desert at Quartzsite for three months. Some of those people find a large solar bank is cheaper. So it all depends on what you want to do.

[Domo]

My Resprionics CPAP runs off of a wall transformer that supplies 12 VDC to it. I purchased a cord that had a cigarette lighter plug and ran it directly from the batteries when we had a pull behind. It could run all night in that little camper with the two small capacity batteries.

Now, in our MH I plug it into our 120 V and it runs off our inverter and our MH's 4-6 volt batteries all night with no problem. We also use the inverter to run the fridge all night (may come on once unless we keep opening the door), watch TV for a couple of hours and charge our electronics - all without turning on the generator during quiet hours.

A solar panel charging during daylight might be nice - but since it's not quiet hours we'd just crank up the gennie. I do have a DIY Genturi that I hook up if we're staying in a place for more than a couple of nights. The Genturi channels the generator exhaust and most of it's noise up over the MH where it floats away without sneaking in through our slide seals or open windows.

We lived for a week "off grid" the the Albuquerque Balloon Fiesta with zero problems.

[LI-Camper]

We run two C-Paps daily when camping with no hookups. I bought two portable lithium batteries from Amazon that are made for running many different brands of C-Paps. These are called MaxOak brand batteries. They are expensive ($300 each) but will run a C-pap without heated hose or humidifier for about 5 or 6 nights on a single charge. I have charged them using my two solar panel system (180 watts) during the summer. I usually fully charge the two of them every day because you never know when it may get cloudy for several days in a row. I have tested them at home to verify that I can get 5 or 6 days without charging. We use two identical Phillips Respironics C-Paps. I have even used the batteries at home during a power outage that lasted a couple of days. If you want to use the heated hose and humidifier you could get 1 or 2 days without charging depending on the C-Pap and the number of hours of use. With these batteries you may be able to run the O2 generator on the house batteries overnight. My house batteries are two 6v golf cart type so running the A/C is not possible. This is a possible solution that would not break the bank.

[153stars]

You should be able to find the power to run the breathing items without breaking the bank. For AC add micro air soft-start with a quiet inverter generator and or maybe a hybrid inverter . Could keep you at a quiet drone and not have genny revving way up to start AC. A further sound deadening box /hut around genny can help further.
If your camping in heat Im guessing others will be running gennies and ACs. Tents 50' away may be unhappy.

[ByeTheWay]

Originally Posted by MichaelInNM

We NEED to run 2 CPAPs, an O2 concentrator, and ideally AC through the night to sleep. I was under the impression that with several batteries (I was told 8) this would be fine running on house batteries for 1 night, and then that I could have a solar setup on the roof that would recharge the batteries the next day. Therefore while boondocking I wouldn't need to run my generator at night and make all of my neighbors want to slash my tires at 2am.

Spoke to a Newmar / Tiffin dealer here about this when looking at a coach we may buy and he said it's not possible. If not hooked into shore power you must use generator to run my required accoutrements. Said solar is only to trickle charge chassis batteries and only would charge a little bit- roughly the parasitic draw while parked and then some.

So- what's true? Am I going to end up being the guy that has to park at the far end of the park, or can I get what I need while leaving neighbors with the sweet sound of silence?

Any input is appreciated.

I see no mention of how much solar you have. If your referring to the small stock panel sold on many rv's, your salesman is correct. That panel is to keep your batteries up in storage.

How many amps does your 2 CPAPs, an O2 concentrator require overnight? Batteries should not be discharged more than 50% on a regular basis. Also Campgrounds without hookups have quiet hours too.
And if you do need to run your generator all night, people will be upset.

[429CV23]

My 750 watt solar, 6 battery system can run everything in the coach, including a residential fridge all night without issue.
You may need 8 or more batteries, and a 1000 watt solar system.

Maybe even run the CPAPs on the small battery packs available now, Zopec, etc to extend power usage.

[Ray,IN]

Originally Posted by geordi

Unless you want to install somewhere around $15,000 in lithium batteries, running the air conditioner overnight is just not going to happen. That said, the dealer guy is a moron (not unusual) and doesn't know what he's talking about - which is not uncommon at all either.

I can't comment about the other devices without more information - they should each have a sticker or label near the power cord that says how much power they need in two of these three things: Voltage, amperage, watts. Ultimately you need to know the wattage to know how long these things can run on X amount of power from an inverter and batteries, so let's start there.

But solar is used to charge batteries, and how much solar you need is a function of how much power you need PLUS how much sunlight and time you will expect to have.

Figure all your calculations on having just 5 hours of sunlight per day, and size the system accordingly. Solar elements are pretty standard size, so a panel that produces 350 watts is going to be about 40"x80" so you need to know that you have enough roof space for that - times the number of panels you want.

With enough money you can even go to the moon and dry camp.