Breakeven Point of Solar?

[Mitch Nelson]

Hey everyone. Starting to plan a reno to a 60's silver streak trailer.

I'm aware of all of the work that needs to be done before I actually start the work, but I'm torn on power in the trailer. I've read/researched a ton on solar vs generators but I just want to get a few different opinions on thoughts about solar.

I know solar can be spendy and is all based on the use of the trailer. I plan on using the trailer for 3-4 one week long trips every year between April and October. Also plan on using for long weekends throughout the year as well. (Also plan on parking on my land and Airbnb renting it out for some time not in use, but this shouldn't play a role in my decision). With the week long trips, we have discussed boondocking or minimal campground experience where our weekend trips are likely going to be local campgrounds with power hookups on the sites.

At what point of use do people value solar over generator power? I know people who boondock regularly need it, and it pays for itself overtime not having to pay campsite fees but I'm torn with this.

Thanks for the help.

[mikeinca]

On a strictly cost basis it's probably difficult to justify solar over a generator. However there are intangibles that are harder to quantify in dollars and cents.

There's a lot to be said for not compromising a quiet boondocking site for yourself (and your neighbors) with a generator. I don't know how you put a dollar value on that but it's worth something, to me anyway. Also, unless you're planning to run the generator a lot you may want to upgrade to lithium batteries and an uprated converter in which case you've probably invested half of what it will cost to go all the way to solar. Plus installing solar on your RV qualifies for a tax credit.

You've done the research so you know the numbers. I don't think having solar is an economic decision so much as a lifestyle choice to have a clean, quiet power source. Only you can decide if that's worth the money.

FWIW, we're headed out tomorrow for Grand Tetons NP and we're staying at a minimal services NP campground that does not allow generators. I'm looking forward to the peace and quiet.

[OutdoorIdaho]

From a cost perspective, a decent brand invertor generator could be more expensive than a modest DIY solar installation.

Personally, I rely on solar but bring along a generator for backup.

Edit: There are some less expensive generator options so it would depend on how much capacity you are wanting...

[OutdoorIdaho]

Another comment, I do like the passive charging of solar. I can go for a hike during the day and return to fully charged batteries.

[richard5933]

Nothing in the RV world can be justified on a cost savings basis, with very few exceptions. Same for solar and/or generators.

To me the question is which will serve your needs better. You won't be happy boon docking to save a few bucks on campground fees if you don't enjoy boon docking. Same for campgrounds - you won't be happy in a campground just to plug in if your goal is to enjoy the wilderness or back country.

Figure out what your goals are, then buy/build a rig to meet them.

[nryn]

One way to split the difference would be to plan for a future solar install or an incremental solar install. While you have it gutted, run the appropriate cables up to the roof (this seems to be the most disruptive aspect of a solar install) and install a junction box. If you aren’t starting with a lithium battery bank, pick power components that will allow you to grow into one. Moves like this would save you the up front expense (if that is your concern) but allow you to easily expand later should you want to.

I may be wrong but as far as I know a lot of people with even large battery banks and solar arrays travel with a generator. It’s isn’t exactly an either/or thing. As for me, I have about 360W of solar on my roof and for the most part it is sufficient to charge my two batteries. I’ve only had to break out my generator a handful of times and was glad to have it. But if at a state/national park, given a choice between camping in a generator loop and a non-generator loop, I would much rather be in a non-generator loop. Solar gives me that option.

[jimdelane]

Solar and generators are apples and oranges.
Solar is a onetime install cost with no further maintenance or repairs.
Generators have a lower initial cost but you will have the cost of gas, oil, plugs, maintenance and time.... and eventually you will need to replace it. The more you use it the sooner you will replace it.
Solar is like lithium batteries. There is a higher initial cost but after the install, you are free to enjoy other things. Also, should you install lithium batteries, they charge up a lot faster and maintain higher voltage longer. With a solar/lithium combo you have more energy per pound and a maintenance free system that should last you 10 or more years.
I would recommend that you buy a cheap generator to carry as a back-up to charge should you have a week of bad weather. I know a few people that have a solar/lithium combo with a back-up generator that have used the genny maybe once or twice per year. Some less than that. That is how you get a genny to last 10 years - you do not use it much.

[uncle_bob]

Hi

There are a surprising lot of places that simply do not allow you to run a generator. There are some (Walmart parking lot) that may not make that rule explicit, they just ask you to leave at 10 PM ... yuck ....

Once installed, solar is "free" (nothing is ever free maintenance wise ...). Four 100W panels can be had for $400. A controller might be $200. On a raw parts basis, that compared pretty well to a quiet Honda generator at about $1000 or so. Yes, you still have labor and a bunch of fiddly parts on the solar. You also have a fuel tank for the generator .... The main point is only that it's close.

Budget wise, I'd put Lithium ahead of solar or a generator. In terms of extending the usable range of the vehicle, it gets used on every trip.

Cost wise here's some math:

Drive out / drive back, stop each way for the night. Full hookups $45 vs free. $90 a trip 10 trips a year, you have $900 in the slush fund per year.

Longer trips with multiple spots, toss in two more travel days. That's another $360.

What are the capital allocation rules you operate under? Is 9 months to long for approval? Is three years the target? Do you run out to five years?

At 5 years, whatever the enhancement that got you there, you have $6,300 to spend.

With any calculation like that, you can change the basic assumptions and make it come out any way you would like it to. Welcome to justifying any project like this in any environment I've ever done it in ( and I spent many decades justifying projects ....).

Bob

[vanster]

I have a solar panel on the roof along with a suitcase. I also have a generator that carry in the back of our TV. We seldom use the generator. A, it noisy (52 DB ) B, many state parks do not allow them after 8pm. You have to carry extra gas, not a good deal for a generator only runs for about 8hrs, last I checked solar runs for a bit longer...it's a no brainer.

[jnm30327]

There are relatively inexpensive ways to add solar. I have a 2018 Flying Cloud prewired with socket for a Zamp solar panel. I bought a 160 watt Zamp suitcase panel and connect it when dry camping. In normal summer use without AC, I use about 45 amp-hrs from 12 V system. The suitcase panel pretty well covers that use. It takes some attention to keep it oriented to the sun but sometimes I just lay it flat on the ground and leave for the day. I went all summer without running the small 1000 watt Honda generator I carry. The longest period of dry camping was 7 nights. NB: no solar is strong enough to run AC.

The unit I have seems to no longer be available. Currently a 180 watt suitcase system from Zamp costs $800.

[ROBERT CROSS]

Originally Posted by Mitch Nelson

Hey everyone. Starting to plan a reno to a 60's silver streak trailer.

I'm aware of all of the work that needs to be done before I actually start the work, but I'm torn on power in the trailer. I've read/researched a ton on solar vs generators but I just want to get a few different opinions on thoughts about solar.

I know solar can be spendy and is all based on the use of the trailer. I plan on using the trailer for 3-4 one week long trips every year between April and October. Also plan on using for long weekends throughout the year as well. (Also plan on parking on my land and Airbnb renting it out for some time not in use, but this shouldn't play a role in my decision). With the week long trips, we have discussed boondocking or minimal campground experience where our weekend trips are likely going to be local campgrounds with power hookups on the sites.

At what point of use do people value solar over generator power? I know people who boondock regularly need it, and it pays for itself overtime not having to pay campsite fees but I'm torn with this.

Thanks for the help.

It's hard to amortize any unneeded purchase, if it's something you will use and want to spend the $$$ on...do it.

We started with a genset and worked up from there, we still use one.👍

We now do have 360w of Zamp portable solar.

Disclaimer...we have never been told generators are banned. We don't 'Glamp' in the resort grounds.

Bob
🇺🇸

[Mitch Nelson]

Awesome insight everyone.


Greatly appreciated. We don't plan on living in it which makes this more of a difficult decision but I like the idea of having the battery bank with the wiring prepped for the panels if we deem it necessary.

Just kind of a tough place to start when designing/planning for everything.

[Bill M.]

The break even for solar is if you want it enough to pay for it you are even.

[Bob Peahl]

Originally Posted by Mitch Nelson

Hey everyone. Starting to plan a reno to a 60's silver streak trailer.

I'm aware of all of the work that needs to be done before I actually start the work, but I'm torn on power in the trailer. I've read/researched a ton on solar vs generators but I just want to get a few different opinions on thoughts about solar.

I know solar can be spendy and is all based on the use of the trailer. I plan on using the trailer for 3-4 one week long trips every year between April and October. Also plan on using for long weekends throughout the year as well. (Also plan on parking on my land and Airbnb renting it out for some time not in use, but this shouldn't play a role in my decision). With the week long trips, we have discussed boondocking or minimal campground experience where our weekend trips are likely going to be local campgrounds with power hookups on the sites.

At what point of use do people value solar over generator power? I know people who boondock regularly need it, and it pays for itself overtime not having to pay campsite fees but I'm torn with this.

Thanks for the help.

We recently returned from two months in the West, including 8 nights in the Tetons and Yellowstone NPs. We carry a Honda 2200i, which is a sweet little gen set but by the end of the trip, I became convinced that solar is the next mod to our 2017 FC27FBT. The parks with generator loops restrict use to 8 AM to 8 PM and I do not like running the generator unless we are home to supervise. Because we preferred to tour and not babysit the generator, we ran the gen for about 2 hours a day - not nearly enough to top off the batteries after a night of furnace use. We got by, but the batteries really took a beating when the furnace was required (temps in the 30's). I envied those who were charging by the sun all day.

If I were you, I'd design with solar in mind, and carry a small gen for shady days or running air conditioning.

[uncle_bob]

Originally Posted by ROBERT CROSS

.....

Disclaimer...we have never been told generators are banned. We don't 'Glamp' in the resort grounds.

Bob
🇺🇸

Hi

Yup, Cracker Barrel is pretty high end. Walmart seems to have moved "upscale" as well .... just have to drop them off the list

Indeed, some folks have *very* loud generators .....

Bob

[ROBERT CROSS]

Originally Posted by uncle_bob

Hi

Yup, Cracker Barrel is pretty high end. Walmart seems to have moved "upscale" as well .... just have to drop them off the list

Indeed, some folks have *very* loud generators .....

Bob

CB & Walicircus?? ...The food sux in one and the dress code in the other scares the mart outt'a me. We avoid both at all costs.

Bob
🇺🇸

[ROBERT CROSS]

Originally Posted by Mitch Nelson

Awesome insight everyone.


Greatly appreciated. We don't plan on living in it which makes this more of a difficult decision but I like the idea of having the battery bank with the wiring prepped for the panels if we deem it necessary.

Just kind of a tough place to start when designing/planning for everything.

We went KISS and just charge two Zamp 180w portable panels thru the 7pin umbilical.

Bob
🇺🇸

[jncd2000]

Is the standard conversion to charge lithium batteries 180watts per 100Ah lithium battery? Thank you!

[richard5933]

Originally Posted by jncd2000

Is the standard conversion to charge lithium batteries 180watts per 100Ah lithium battery? Thank you!

amps x volts = watts

If you're interested in adding time to the equation, then this:

amp hours x volts = watt hours

A lithium battery (or any 12v battery) with 100Ah of capacity will have approx. 1200Wh of capacity.

Here's a page with lots of helpful conversions:

https://convert-formula.com/

[uncle_bob]

Hi

Simply to be utterly confusing .....

It is perfectly "legal" to take the battery voltage minute by minute and multiply that by the current minute by minute. You then add up all those tiny power numbers.

Why does this matter?

A lithium spends most of it's "discharge life" at or above 13V. This gets you to a ~1,300Wh number rather than 1,200Wh. It's *exactly* the same battery. Nothing changed in how much power you are getting. They just changed the math. One is quick and easy to calculate, the other one ...not so much.

Guess which math approach the marketing department likes better?

Bob