Self Sufficient on Solar? Something Not Right !

Solar for us frees us from the daily grind of listening to the generator. I know it would take us years to recoup even the small amount we have into the systems but you can't put a price on silence.

Hi RJ,

It is good to have some real numbers on fuel consumption instead of estimates.

For weekend and week at a time travel, running the RV as an "electric" coach, I was self sufficient with 256 watts of solar, because I had a medium size battery bank. Now that I am full time this is not the case.

I hope to find a way to add 800 more watts. What would be ideal would be an awning that was a solar panel. I am hoping I'll be able to run the air conditioner via solar/battery bank/inverter and stay "even" on the battery charging.

Current weather conditions are -13.9 c (7 f) and I'm using about 3600 watts to keep at 20 c (68 f). At -31 c (-24 f) I need up to about 5000 watts to heat 100% electrically. If I were heating with propane I'd have to refill every three days (one day cushion, to keep from running out). It would cost about $15 per day.

It would be impossible to do 3600 watts of solar on my class c, and the Yamaha generator only does 2800 watts continuous. Filling it every five hours costs about $28.00.

These numbers make campground prices look extremely attractive, when they include power.

RJsfishin wrote:
I'm happy w/ my small 200 watt solar, but it dawned on me the other day that if the sun hangs in here as long as I do (here in QZS) I will have saved a whole $60 of gasoline I usually burn in my Honda 1000 in a couple months. Not a terrible return on a $300+ solar investment, I thought.
But when I found myself going after my 2nd tank of propane @ 50 bucks a trip, I realized something about this self sufficient solar ain't workin quite right.
Just curious, how many are running their electric heates on some of these chilly nites,.....meaning how many more watts of solar do I need ? :)

Or maybe a better question,...how many solarers are still buyin propane. Maybe we don't have this solar all figured out yet ??

smkettner wrote:
RJ, Get a sleeping bag rated for the low temperature and leave the furnace off. ;)
Now that is camping....

With some additional solar/battery a heated mattress pad might keep the furnace off at night. These things will roast you out of bed if left on high.

I'm too old bro, just too old. :) We like the temp to be very consistent. Don't want to go to the bathroom or get up in the cold. I forgot to mention that RV heaters wake me up too much. Remember, WE WANT IT ALL!!!!

RJ, Get a sleeping bag rated for the low temperature and leave the furnace off. ;)
Now that is camping....

With some additional solar/battery a heated mattress pad might keep the furnace off at night. These things will roast you out of bed if left on high.

As gator said, RV heaters are not efficient. Then you get into what heater to use and then it gets into the fact that non vented heaters are not intended to be used while sleeping. You just opened the door to lots of reading and many opinions.
The vented heater that seems to be the best improvement is the "Cat platinum". Its vented, thermostatically controlled and not too bad on your battery (5 amps for 2 minutes each time it comes on and .7 amps for exhaust blower). Your solar setup would probably be able to keep you battery up easier with the amp draw of the cat than the RV heater.
The inexpensive way to go is a Buddy but then you get into venting, uneven temperatures, moisture, risk and an individuals susceptibility to even very small amounts of by products.
On top of all that is the issue of running the a/c. If you need a/c then you are a plug in or generator guy. Many who are big on solar are moving with the seasons and not running a/c. They are also getting by with buddy's or similar when they cant escape the cold.
I looked at it this way.
If I ever want a/c, hair dryer, microwave then I'm sticking with a genny

If I ever get to the point that I can do without those things completely, I'll go solar.

Maybe I would go some solar to help out but its a high price to pay and more weight for the benefit.

I'm NOT saying you can never run a micro or coffee heater with an inverter etc.

Ok ok I probably went on too far. :)sorry

Solar to me is not to save money on generator gas, which is a trivial cost. Solar is what lets us stay off grid many days/weeks in a row without having to find shore power to get the batteries back to working right from doing too many 50-90s in a row. (RJ doesn't have that problem, so his reasons for solar would be different) Solar costs quite a bit so you would have to run the gen a lot for battery charging instead to pay for the solar.

I don't know of a way to save on propane using solar/battery. Maybe with an electric blanket instead of the furnace so much, but not with a big electric heater instead of the furnace.

Propane is only a problem if it is difficult to get a refill where you are camping off-grid. Mex complains that it costs more for gas for his truck to go get the propane miles away than the bottle of propane itself costs ISTR.

Some seasonal (five month stay) campers at our summer campground arrange for a big propane tank next to their rigs and get propane delivery service for that. I find it is easy to just take a 30lb bottle to a garage for a refill every so often (costs about $29 usually)

Gas for the generator is also easy for me where the gen always stays in the back of the truck so I fill the gen when I fill the truck at a gas station. It all goes on the same bill and I don't even notice how much was for the gen out of that. Not much.

Propane heaters that are built into the RV are very inefficient. That is why you are burning through propane. As for solar, to be close to self sufficient with solar based on your rig, will require at least 700 watts.

We have total of 1000 watts, do not need to elevate. I average about 29 Amp hours from 10am to 4pm. 660 Amp hours of battery capacity. This will get my batteries back to float mode.

We recently installed a Mr Heater Big Buddy. Used 3 gals of propane in 8 days. Used this to take the chill off evening and mornings. This raise the temperature from 59 to 67 degrees in 1.5 hours (early mornings). My question is what is it you really want to do? Are you trying to limit cost or just trying to limit your carbon footprint?

What I had to do was setup my battery banks to run all the thing I wanted to run during the one day/night battery run then successfully re-charge my battery bank each day using my 2KW Honda Generator to power up my OFF-ROAD trailer which will recharge the batteries in a quick three hour generator run time using smart mode technology.

Once you get very successful doing this then you can start adding solar panels to keep from having to run the generator every morning for three hours.

The 120WATT SOLAR Panels will only give you around 5-6AMPS of useful current so when you do the math you find out you are going to need several solar panels if you want to have your bigger battery banks charged up to their 90% charge state in order for you to make the next day/night run off the batteries.

I have found out I have to have my generator on-board as it will charge my batteries rain or shine. Just a couple of Solar Panels are not going to give me 90%-100% charge of my batteries during a one day HIGH SUN day where we usually camp at... It may be cloudy for a whole week haha...

If you just want to run a light or something small then your solar only will work for you. If you want to run all the things you want to run in the one day/night run it will take many solar panels to get it done.

My battery run is so large I will most likely have to run my generator each day for at least a two hour run to get the high current charge of 20AMPS per battery out of the way and then let the the solar panels provide the rest of the day producing the 5-6AMPS of battery charge from each solar panel and hopefully get my battery bank up to its 90% charge state then so I can do the high current battery drain that night running my appliances.

My roof-top area of of OFF-RoAD POPUP will support a good 360WATTS of Solar panels and i will have two of them that will have quick disconnects so I can move to the ground and sit in the high SUN better if necessary. I will be tickled pink to be able to run my 2KW generator during the morning for a couple of hours when allowed to run them at the camp grounds and then let the SOLAR PANELs take over and get my battery banks up to at least their 90% charge state.

This is how I am looking at successfully using my Generator and SOlar Panels for my off-road POPUP activities here mostly on the East Side of the US. Successful meaning I will have power all day and night to run my needs no matter what the conditions are.

Roy Ken

Is the question "can I run an electric heater off my solar system?"
You can briefly but trying to build an off grid solar system to power electric resistance heating is impractical and expensive for a permanent home. It's an even worse proposition in an RV. The main problem is storage. That's what's hampering the whole solar industry right now. Battery technology is terribly inadequate for heating.
To give you a reference point, 2 golf cart batteries in series hold about 2,640 watt hours of electricity. A 20 pound propane tank with 4.7 gallons of propane holds the equivalent of 126,000 watt hours. So, you'd need 96 golf cart batteries to hold the energy in 20 lb LP tank.

Its all about ampere hours in vs ampere hours out. A 200 watt solar is not going to power a 1500 watt heater very long.