Solar Rv awning -- does it pencil out?

[profdant139]

Great idea, but at ten thousand dollars for a thousand watts, I'm not sure it is worthwhile for me:

Article

[Skibane]

profdant139 wrote:
If I were entering data on that spreadsheet, I would need a separate column for an intangible cost: the noise and smell that accompany generator use.

Using propane as generator fuel greatly reduces exhaust odors - The primary combustion byproduct is just water vapor.

[StirCrazy]

Timmo! wrote:
Well bless your heart StirCrazy...

325 watts @ 12 volts = 27 amps. (The worksheet calculates 300 watts = 25 amps)

My Honda generator produces 133 amps (this has not changed).

Yes the table may be a decade old, but that does not change the accuracy of the breakeven results...5.4 years if the generator is used 1954 days.

How many years do you calculate as your breakeven number?

fills my battery every day I use an average of 80 - 100 AH and I didnt have to but a generator which is 2400 bucks up gere for a honda 2000. watching the amp outputs when I first put it on I could average about 168 AH replaced a day, on a real sunny day close to 200AH and on a rainy day that is dense overcast about 60AH. I also dont have to bring gas, no maintenance.. I would say I broke even the first camping trip where I could use my inverter freely and didnt have to worry about the batteries, but that was just a satasfaction thing, in reality well befor a year... my batteries are full by say 12 to 2pm at the laitest and the rest of the day there doing there equalization or offsetting any other 12V use so they are still at 100% when it gets dark

I think a comparason like this is realy kinda silly, they dont compare. if your buying a generator it is more of a incase thing, or a I want to run my AC thing and I cn get that. I wouldnt turn down a built in genny in my next camper, but I would probabmy never use it inless I was camping in another heat wave and needed the AC.

if you buying solar it because you dont want to carry fuel, load/unload a genny, have noise, or think about it.

trying to pass things off using pricing that is way way out to lunch just to make it sound better or justify why you have a genny is just as ignorant in my opinion. use real numbers and real stats. if you take your rv converter size thats the most charging you can get, take the more strictor campground generator policys for how much you can run it and get proper pricing and comparesons then I'll buy it but its hard to put a paid off pricing on anything.

I guess with my solar, I could look at how many times I was boon docking instead of being plugged in to calculate it if thats the case it paid for its self in about 15 nights, or 1/4 of my camping year this year as this was the first summer I realy used it.

[pianotuna]

noteven,

Recommended charging rate for Li is 0.2 C Maximum may be listed as 0.5 C. Slower charging works well with LI--just stop at 90% state of charge. Li can be charged faster--but cycle life is impacted adversely. The big plus is not having to charge to 100%. Once a month it is good to take them to 100%, to reset the battery management system. Li has too many hoops to jump through for me. I've boondocked at -37 c (-34 f), which makes LI undesirable.

At 80% state of charge, lead acid self limits to 12.5 amps per 100 amp-hours. As a C rate that is 0.125, of course it goes down hill from there as it gets closer to 100%. But lead acid WANTS to be taken to 100% state of charge.

I prefer SiO2 to Li as they enjoy 100% but do not require it except once ever 30 cycles. Their recommended charging rate is 0.25 C

[noteven]

I think the charts for my PD 60amp Converter charger with charge wizard says it takes X hours to bring wet cells to 80% SOC and 2 more days to 100%.

It’s why in my untrained mind wet cells and agm work so well with solar if the sun shines and fast charging batteries like lithium work well with fast sources of charge or Big Solar if the sun shines.

[pianotuna]

profdant139,

With modern batteries such as SiO2 that are not "destroyed" by partial charging nor deep discharges, a generator becomes even less needful.

I went 5 years with zero generator use. Then I made a mistake and got a generator. In hind sight, I would have been far better off to redo the solar.

[profdant139]

If I were entering data on that spreadsheet, I would need a separate column for an intangible cost: the noise and smell that accompany generator use.

I have a Honda 2000 and almost never use it (except at home when "exercising" it during routine maintenance). For us, silence and the smell of the forest are both very valuable -- we live in the dense suburbs of Southern California, and escaping that environment is one of the reasons we go camping.

That's especially true since we are avid boondockers.

So how to quantify that variable?? I don't know. The Honda is a "sunk cost" -- we have to have it in case the sun does not shine and our panel does not produce juice.

[Timmo_]

Well bless your heart StirCrazy...

325 watts @ 12 volts = 27 amps. (The worksheet calculates 300 watts = 25 amps)

My Honda generator produces 133 amps (this has not changed).

Yes the table may be a decade old, but that does not change the accuracy of the breakeven results...5.4 years if the generator is used 1954 days.

How many years do you calculate as your breakeven number?

[StirCrazy]

Timmo! wrote:
Here is a link to Solar vs Honda financial breakeven analysis that will help determine which source of power is cost effective. This analysis indicates for the Honda 2000, it will take about 5.5 year breakeven, or around 1954 days of usage.



https://www.nroa2003.com/download/Miscellaneous/Cost_of_Solar_vs_Honda.xls

Of course the breakeven analysis for carbon emissions is a different story all together. At what point does the accumulated emissions from the generator's manufacture and operation match that of the solar panel emissions? If we take a page from the BEV's breakeven analysis, then it probably is several years away for heavy RV users and probably never for the occasional weekender.

thats kinda of a outdated table, must be from the 90's. I did a complet 325 watt system for 600 cdn, probably would have been about 3-400 down there if that. also you would never be able to charge your batteries enough to totaly recover from a 60AH draw in any offical campground up here as you limited to to hours of generator use in the morning and 1 to 2 at night in most places. some will give you and extra hour here to there, some say no generators period, and more are going that way.

the other thing they have in that graph is the unrealistic charge rate from the generators, if you have a 45 amp converter in your rv, all your getting is 45 amps and that is if everything else is turned off and dependent on the stat of charge of the battery. if a flooded battery is down 60 amps its you can assume probably 4 to 8 hours of charge to get to 100% depending on the equalization phase and how much actualy amprage your 45amp converter is actualy sending to the generator.

[StirCrazy]

time2roll wrote:
$10 per watt is on the high side. Pass.

ya the very very high side, its only about 0.60/watt up here and probably cheeped down there.

Steve

[Timmo_]

pianotuna wrote:
Timmo solar is under $1 per watt installed.

Where are you buying fuel at those prices today?

You have not factored in maintenance. My Yamaha wants oil every 50 hours. If I relied on it totally and ran 24/7 that's every two days, two hours.

I am not the author of that excel spreadsheet, but the variables can be changed easily. Just saying this analysis indicates the financial breakeven is years for heavy users...probably never for weekenders. If my conclusion is wrong, then please correct me with your facts.

My Honda 2000 cost me about $750 a decade or so and is running strong (equivalent cost of $0.375 per watt (2000w) and $0.469 (1600w)...about 2-3 times lessor than your $1/watt system). In my world, it takes me less than 2 hours each morning to fully charge a pair of 6 volt golf cart batteries. We use our TT about 60-70 days each year.

[valhalla360]

pianotuna wrote:
Timmo solar is under $1 per watt installed.

Where are you buying fuel at those prices today?

You have not factored in maintenance. My Yamaha wants oil every 50 hours. If I relied on it totally and ran 24/7 that's every two days, two hours.

Not in Canada but in a lot of the USA, it's still a reasonable long term assumption.

Odd, my Yamaha calls for oil change every 100hr.

If you just need to charge the batteries, solar is a good option. Generator's make sense when you need high load, longer duration output.

[Skibane]

pianotuna wrote:
Timmo solar is under $1 per watt installed.

With batteries and AC inverter?

[pianotuna]

Timmo solar is under $1 per watt installed.

Where are you buying fuel at those prices today?

You have not factored in maintenance. My Yamaha wants oil every 50 hours. If I relied on it totally and ran 24/7 that's every two days, two hours.

[Lwiddis]

“You get charging-while-driving from the engine in the tow vehicle or motorhome anyway…”

Not that much goes through that tiny little wire, Ski.