Questions about the value of solar

[Tony Lee]

Prove or disprove anything by selecting the right figures to use. (Li battery exponents are masters of that art)

The 12 cents per kWh is a red herring simply because you can't pull up at a lamppost on the side of the street and plug in. First pay the campground fees.

The one I see as more legitimate is to save campground fees of 30 dollars a day by boondocking for free.

30 x 365 pays for a pretty good solar system in just a year. $10950 to spend on a solar system WooHoo!!!

For that matter it would run your big generator for a lot of hours per year too.

That calculation worked when solar was $5 or more per watt and now that it is under $1 per watt it is no contest at all. Add in freedom of choice and the ability to fire up your coffee machine at 6;30am instead of pacing around outside with trembling hands waiting for quiet hours to end so you can fire up the generator and the contest is over



200 Watt panels are a reasonable size and fairly good for fitting in between hatches and antennae. Most solar regulators are MPPT and can accommodate input voltages of 12V or 24V nominal and even higher so that isn't a major issue - but of course series strings may be more affected by shading. Bigger the panel the cheaper per watt usually but I worry about the large unsupported area trampolining up and down with every bump in the road. I add foam blocks between the roof and the back of the panel to provide dampening just in case

[cruzbill]

Speaking of right figures, ya gotta dump your tanks sometime somewhere, so maybe 365 isn't exactly accurate.

[MisterT]

Originally Posted by Tony Lee

The one I see as more legitimate is to save campground fees of 30 dollars a day by boondocking for free.
30 x 365 pays for a pretty good solar system in just a year.

while I may lament the solar calculations as being somewhat 'less' beneficial than most of us might be led, you point is well taken. I used it to justify our 2-100w panels because we were going to and from Alaska over June and July of last year. Knowing the many options for dry-camping along the way, and the ability of up to 20+ hours of sunlight, I could economically 'justify' the purchase of 'quiet' power, offsetting many hours of usage of the diesel generator.
my calculations of the amount of hours of savings of generator diesel were not accurate, but merely a 'guesstimate' since it's also VERY difficult to actually calculate generator usage costs. None of these are static numbers, and therefore left to the user to 'guess', on their own, to justify, or un-justify, the costs.

I felt the benefit outweighed the cost, since the panels might fairly pay for themselves during that time, or at least partially, expediting the 'cost versus time' calculations. Did they? Who really knows. Would we have been fine with running the generator whenever needed? Sure. Did we have full sun at all times for the Solar panels? Of course not. No. You NEVER will.

It's never a 'all or nothing' proposition, it's really just a guesstimate, but hopefully, when it's all said and done, you're not just spinning your wheels.

p.s. as for Tony's calculations he mentioned above, that's also an unrealistic point of view. Many folks would dry-camp regardless of solar or not, that's why we have batteries, inverters, and generators. So, to assume that having Solar is the only power source that allows you to 'save' $30 on rv parks and campgrounds is an unfortunate view. We've certainly dry-camped many a many a many a night in paid campgrounds, free parking lots, and free 'on the side of road' - all before solar.

[Itinerant1]

Originally Posted by nothermark

It's hard to believe that the payback period for big solar will be rational for anyone full timing who does not migrate to better places in the really hot weather and is not dry camping a large part of the time. By that I mean less than 10-15 years. The chances of keeping the same MH with the same setup for that long seem low.

Low yes, impossible no.

[Old Scout]

.....wonderful conversation here--yup, I am in for 500watts of solar with an MPPT controller, and six, 6-volt, house bats on my 40ft DP. Installed it myself for around $800. We don't dry camp much, so project was mostly curiosity for us. Agree, its a "starter" system but unless you also control amp consumption, you don't get much for it--a few less generator hours is about it. So here is the rub--parking in the sun shine to get most solar time, and you need the A/C; park in the shade to reduce A/C heat load and you lose solar. Get portable panels and find them gone when you return home--so what to do??????

[nothermark]

FWIW I'll toss this in. There seldom quiet hours where free camping. That is why the idea of starting up the generator first thing in the morning both off loads the heavy draw of the Keurig (gack), microwave, water heater, furnace, etc while bulk charging the batteries. An hour or two then leaves the solar to finish off the charging at a slower rate the batteries are happy with while taking on small loads like TV or computer charging. Lighting today is minuscule. That let's the solar be significantly smaller than trying to do it all and keeps the generator exercised. All in all a win/win proposition.

[Tony Lee]

p.s. as for Tony's calculations he mentioned above, that's also an unrealistic point of view. Many folks would dry-camp regardless of solar or not, that's why we have batteries, inverters, and generators. So, to assume that having Solar is the only power source that allows you to 'save' $30 on rv parks and campgrounds is an unfortunate view. We've certainly dry-camped many a many a many a night in paid campgrounds, free parking lots, and free 'on the side of road' - all before solar.

I did say in the same breath that $10,000 would pay for a lot of fuel for the generator too.
The point is that spending a few dollars on solar has lots of potential benefits and it is up to each user to determine what benefits are useful and what are not. Some assume that unless you can install enough solar panel to run an all electric rig under all possible conditions then there is no point in installing any solar at all and that doesn't make much sense either. If I wanted to wake every morning to the roar of generators, I might just as well overnight by the side of an interstate. On the airstream, I only have a couple of piddling small panels installed by the previous owners so on their own they won't do the job, but because we are travellers rather than sitters, I have improved the split charging from the engine alternator so between the two sources the batteries get to 100% most days and then we can use heavy draw appliances such as microwaves and kettles without needing to start the generator. We don't expect to be 100% generator free, but every bit saved is welcome.

My OKA truck, while obviously not being 45' long like some rigs, has pretty much all the comforts of our Airstream MH yet has no propane on board, no generator on board and not even any mains hookup or fixed battery charger yet we can run in relative comfort for as long as our water and food last - all solar powered or diesel powered, so there is nothing magic about living a quiet boondocking life and not annoying the neighbours.

[MisterT]

...

...all these conversations, discussions, and input are valuable, and really point to the simple fact that 'Solar', like any other type of power source, is not an end-all for everyone, or sometimes near anyone. We are all different. We do things differently. We use 'electricity' differently. We are in different places. There's no single power source that is best for all, and for all situations, and it seems, sometimes very few situations...depending on the place, the day, and the folks deploying it.

but, it sure is nice having all the different options. When generators started to be added to RVs as an optional item, I'm sure there were many, many discussions just like these here about Solar. It's just another power source option that gives you options.

Some of us will really make great use of Solar, with big investments and substantial time and effort involved in making sure it pays off, off-gridding to it's fullest extent. Some of us will dabble with the idea, making us feel good that we are part of the 'smart' group who use it. Some of us will reject the idea that it really makes great sense because of the mobile nature of RVing, at least in the way WE do it - resorting with 50a power most the year won't warrant the investment, or provide enough long-term value.


enjoy : )