What is bare minimum solar for off-grid camping?

[Piggy Bank]

I want to understand what may be possible as to solar for a bare minimum setup.

Our rig (2019 FC) has solar pre-wire, and the standard Interstate batteries.

When we camp at a national park we bring a honda generator to top off the batteries.

What would be the alternative to this --using solar?

Is there solar technology at a decent price point that is simple?

I am imagining a portable panel on the ground. Are these simple, small, and inexpensive enough to use? Or do they need different batteries, controllers, panels, etc.

It seems like what I read about solar is the super-intense all-in setup.

What is the bare minimum setup? And what would that allow?

Thanks in advance.

[azflycaster]

We are not big power consumers and a 100 watt portable solar does pretty well for us. We ave a unit made by Renogy and it has a built in control unit which can be used on a variety of battery types. I port the power from the panels to the battery by way of the 7 pin connectors charge line.

If we consume too much power we normally have a portable generator to charge up the battery.

[aftermath]

The bare minimum is going to depend on how you camp, where you camp and when you camp. Are you planning on using a lot of electrical devices? The best answer will come when you decide on some of these issues first.

[mikeinca]

If you're just looking to keep your batteries topped up, which I would consider the "bare minimum", a portable solar "suitcase" is reasonably affordable, easy to use and is a nice alternative to running a generator for that purpose. Price correlates with panel size but, at most, you're looking at under $1K for a 200W panel and considerably less for smaller ones.

We have a portable 200W Zamp unit which plugs in to the provided plug at the front of the Airstream. It comes complete with a built in controller with different modes which are suitable for monitoring the charge on regular lead acid batteries like your Interstates, AGMs, or lithiums. Nothing else is required. The only additional accessory you might want would be an extension cable which I find to be useful in finding a sunny spot if you're parked in an area with a lot of trees.

If you want to run a microwave, AC, or other appliances without a generator then you're getting into those major (and costly) solar/battery upgrades you're reading about.

[ROBERT CROSS]

We did pretty well with one 120w,(new ones are now 140w) Zamp portable when we decided to give solar another chance after a poor attempt with flexible panels 11yrs ago.
We had two Lifeline AGM batteries, and an IOTA DLS 55a converter, kept the batt's up very well, as long as SOL cooperated.

Problem is, it's like a good Bourbon, one sip is never enough.
We now have two 180w Zamp panels charging thru the 7pin umbilical with two Battleborn100ah lithium batteries, charging with a Boondocker lithium charger, Victron
700 series monitor with a wireless dongle.
A DIY system costing 2.8k.

My advise...go with the the largest you can afford.👍

Bob
🇺🇸

[AirMiles]

I would pick one of these Renogy Solar Suitcases with an integrated controller: https://www.renogy.com/products/sola...lar-suitcases/ For $249 you will be able to charge your battery from solar. No need to buy or upgrade anything else. Just connect its alligator clamps to your existing battery and you will be able to live frugally with 12V power. It will work great if you are just using minimal lighting, your water pump and your refrigerator on propane. If you want to use the furnace, inverter with the TV, hairdryer, vacuum cleaner, fantastic fans day and night, the minimum would be a roof full of solar.

[GammaDog]

I travel with 2x100 watt renogy panels in a suitcase I fabricated myself. In warm weather (no furnace use) I can get by setting up a single panel if i have a full sun place for it all day. If it gets cloudy or I’m partially shaded I set up both.

[uncle_bob]

Hi

Do you want to just run the fridge and *nothing* else?

If so, that's typically around an amp of drain. It's 24 hours a day so 24 amp hours. Figure it
as 24 x 13.6 = 326 WH. If you *only* camp in the desert southwest in the summer, then figure 8 hours of "peak solar". You could get by with a 50W panel at 100% efficiency.

If you camp out in the northern part of the country, and have shade, figure about half that solar. You now need a 100W panel.

If it rains, clouds up, you might need enough battery to go for a "dark day" and then catch up. That's now a 200W panel.

All this is just to run the fridge. Most folks run about 2X that power (50AH), even when trying to be frugal. Many run 2X that (100AH) and still feel cramped. Each time you double the usage, double the panel power ....

Yes, there's a *lot* more to it. There are many threads on this stuff. The point is that even the "minimum" comes with a lot of qualifiers ....

Bob

[Atwebs]

While we have used a suitcase solar for a trailer, it requires quite a bit more work than having a rooftop system-which we have now. And, either are better than a noisy, stinky generator!

Our biggest issue was finding a place to set the solar panels that was in the sun, but not where it could easily walk off if we left it while we were sightseeing. They are desirable and easy to heist. It would recharge the Interstates enough for one or two nights.

Not an issue with the rooftop, but we also swapped out to better batteries. We have never been low on power or had to fiddle with the panels. The trailer always has enough power to do whatever we want and we don't even have to switch them on and off.

We wasted a lot of time when the trailer had no power, the solar suitcase got hooked up wrong (the clamps slipped, we misplaced a cord or it wasn't completely plugged in) or we decided to take the solar off when going for a day trip. Worse, hunting down replacement Interstate batteries because yet again, they had failed.

I would highly recommend spending a more and going built-in. Now, we never have the hours trying to find sun, batteries or parts.

[Camr]

Just a quick question. I notice a couple of references in posts above referring to charging through the 7 pin umbilical cord. I assume this refers to the coach/tow vehicle cord. The wire gauge is so very thin that I can’t imagine the wire allowing more than a minuscule amount of amperage from any panel.
My system uses a large Anderson connector directly to the battery using 6 gauge wires from a 120 watt panel. Using an ameter, it shows 7.9 amps of charge at the battery connection.

[JeffCross]

We have 2 AGM batteries and 180 watts of solar on top of our 22 ft AS. I understand that Zamp is probably the most expensive, but I chose to go with it anyway through AMSolar.com. As a rookie at installing and understanding the process, they helped me with all of the necessary hardware and knowledge to install the 100 watt panel on the roof. (We already had an 80 watt panel preinstalled.) I found whatever I paid extra for the Zamp brand to be more than cost effective to what I received in return from the people at AMSolar.

The 180 watts worth of panels on the roof and the 2 AGM batteries are more than sufficient to meet our needs.

[Sport 16 STL]

Solar panels are fairly inexpensive. The rest of the gear is not. I would start with a couple of the largest panels on your roof. They are always working as you drive and parked. Since you are pre wired it is a simple install. The one item you need to add is a charge controller. Buy a mppt if you can afford it as it is more efficient. Also get one that works with AGM and lithium batteries if you upgrade in the future. Panels on the roof also helps with battery life as it keeps batteries charged when in storage. More complicated than a suitcase but more advantages.

[jimdelane]

I agree get as much solar as you can. The more you have the more you will use.... it is sort of like any extra space will get filled.

Figure 200 watt panel will give you 200w per hour at best - perfect sun and perfect angle of sun which is rare.

energy is calculated in watts, not amps or volts.
watts=amps x volts

uncle_bob may not have been clear. If you run 24 hours at 13.6w = 326Wh. 13.6 watts might run a couple of lights and fans. 13.6 amps at 12 volts = 163 watts at 24 hrs = 3912 watt hours.
Your battery bank is a consideration. If you have lead acid / AGM then you need twice the needed amp hours, if you have lithium then you do not. Lithiums can be discharged 100% whereas LA batteries should be discharged only 50%. You determine your amp hours by taking the total watts hours and divide by the battery nominal voltage. If you use 1000W and have a lead acid / AGM bank = 1000W/12V = 83Ah which means you need 166AH of lead/AGM batteries. If you have lithium bank = 1000W/12.8V = 78Ah and you need 78Ah of lithium battery.

Determine how many watts you use. Some things like a coffee pot may use 2 amps at 120v AC. No problem 2 amps x 120v = 240W at 15 minutes (1/4 hour) = 60 watts. A fridge that uses 10 amps at 12V DC = 120 watts. And so on.

Most people opt for an oversized battery bank, a gen set and/or lots of solar. Lots of choices, lots of projects.

Do the math and then do the best you can - you can never have enough energy.

[WindyJim]

Costco is now selling a Coleman 100 watt solar panel with controller for $100.
It is not a fold up panel, but one could prop it up, wire it to the solar controller, and put some jumpers to hook to the battery and you would be good to go (for a minimum setup). That would assist in charging the battery, etc., but you would still need the generator to run microwave, air conditioning, etc.

[kscherzi]

The minimum means not using indoor lights, radio, water heater, fridge, furnace, etc. Both the water heater and fridge use some 12 volt power to operate their controls and ignition.

Typical off-grid battery use includes the above and some additional laptop and cellphone recharging, a bit of furnace time too. I recall my old interstate batteries lost around 25% to 30% of useful capacity per 24 hour period typically. Thus good enough for about two days before reaching their safe full discharge limit.

What you use dictates what your minimum solar system should be. My typical use I describe above. I have 400 watts mounted on the roof. In summer in direct sun the batteries fully recharge in about 3 hours. In winter when the sun is low or heavy clouds and shade, the batteries might not fully recharge at all. Of course in winter we may spend more time indoors thus using more power than normal.

[bigfoot390]

We have a 31 excella and have a 100 watt panel on our roof running through the preinstalled solar wiring that airstream uses. Works fine charging stock batterys although I am adding a second 100 watt just for those cloudy days.. we have never gotten even close to running out of power .
I would stay away from those suitcase setups as they tend to go missing and for a little work you don’t ever have to fool with setting it up.
Oh and all my lights are led now.
😁

[JCWDCW]

You asked for bare minimum
My 20 year old 70 watt roof top on my 25 ft AS keeps one Gp 27 battery topped off enough for me dry camping. Granted I don't run the TV but I do listen to the Radio and run the Fridge and Water Heater, and some interior lighting. This is camping above Lake Superior mid summer where I don't generally need the roof vent fans, but they do run occasionally.

JCW

[Hermes]

Originally Posted by aftermath

The bare minimum is going to depend on how you camp, where you camp and when you camp.

Agree. The big factor for us was running the furnace during the shoulder seasons overnight. For one, the sun is not as high in the sky so you need to increase your solar surface to maximize sun energy capture and second you need sufficient storage to be able to operate for days with little or no sun. In our case, 500W (5 panels wired in parallel) and 470ah of battery storage with four industrial deep cycle 6V batteries, did the job. You could also go with the equivalent in lithium batteries if price is not much of a factor to you.

If you plan to camp during the sunnier period of the year or in the southern latitudes, you could manage with half that capacity unless you plan to run many electrical appliances with a larger inverter, etc.

[ROBERT CROSS]

Originally Posted by Camr

Just a quick question. I notice a couple of references in posts above referring to charging through the 7 pin umbilical cord. I assume this refers to the coach/tow vehicle cord. The wire gauge is so very thin that I can’t imagine the wire allowing more than a minuscule amount of amperage from any panel.
My system uses a large Anderson connector directly to the battery using 6 gauge wires from a 120 watt panel. Using an ameter, it shows 7.9 amps of charge at the battery connection.

Bob
🇺🇸

Not really...using 10g👍

[Prettygood]

Originally Posted by Piggy Bank

I want to understand what may be possible as to solar for a bare minimum setup.



Our rig (2019 FC) has solar pre-wire, and the standard Interstate batteries.



When we camp at a national park we bring a honda generator to top off the batteries.



What would be the alternative to this --using solar?



Is there solar technology at a decent price point that is simple?



I am imagining a portable panel on the ground. Are these simple, small, and inexpensive enough to use? Or do they need different batteries, controllers, panels, etc.



It seems like what I read about solar is the super-intense all-in setup.



What is the bare minimum setup? And what would that allow?



Thanks in advance.

Lots of answers so far, some not so simple. You really need to first determine what you will use, and how much electricity those items will consume. Once you know that, you can determine how many watts of solar production will generally match consumption.

The folks suggesting a portable solar panel with built in controller are spot on. No matter what you add later, that portable unit is always useful. Next consider a large (150-200w) single panel on the top of the Airstream and a MPPT solar controller. The combo of the portable and one large roof mounted panel will likely be enough to cover most use cases. You can always add two more smaller panels on the roof later if needed.

Don’t overthink this, but do some assessment of consumption before making any decisions. Good luck.