New solar questions/ponderments/opportunities/gotchas

[khigh]

Right - panels in parallel - 24V

12V batteries in series (assuming only two) - 24V

Between ham radio and an engineering career, I'm actually pretty solid on the electrical hookups and math. I just know precious little about solar from a practical perspective and I'm trying to picture my options in re: what to physically do with the panels in light of the realization I don't generally camp in the sun.

I just don't think I stand to gain a lot on the classic definition of a camping trip, at least without portable panels, but I'm picturing there may be emergency power generation situations where I would just put the trailer where it needed to be for maximum effect.

[MtnDon]

I have put off getting panels for our trailer mainly because I like to camp in the shade when I can. And I have not convinced myself of the practicality of portable panels. I see folks using them but I have had a few things that were not nailed down disappear over the decades. However I have a (low cost to me) high quality PWM controller coming so may buy one or two "12 volt" panels and secure them to the roof. A third of the places we camped in the last two years had great sun / no shade at all. I can't quite bring myself to the cost of a good MPPT controller when I seek out shady campsites.

[desertrat222]

cant wait to get my solar =( im about $600 for what i want. I put lights in my CTC so hopefully i can still run my fridge and lights fri-sun or ill need to buy 2 more deep cycles bats $250.00 or just get the solar! Im going to burningman in June so need something by then to get me though 4 days boondocking it!

[khigh]

cant wait to get my solar =( im about $600 for what i want. I put lights in my CTC so hopefully i can still run my fridge and lights fri-sun or ill need to buy 2 more deep cycles bats $250.00 or just get the solar! Im going to burningman in June so need something by then to get me though 4 days boondocking it!

See that's where geography and camping style comes into play.

There's no shortage of sun at Burning Man

Of course that would be another gotcha for me because I'd have to run AC. But then I'd look into one of those super low power tractor ACs

I looked out my kitchen window this morning and just sighed - looking at that big expanse of flat roof sitting there 350-ish days a year in the sunniest part of my yard just doing nothing... fading.

I'm half tempted just to make a circuit for it in the house and just leave it plugged in.

[desertrat222]

i bought a converter and just installed shore power on mine to get my buy until i get my solar.

[lrrowe]

I am going to do it (install solar panels) not because I need to. I do not even really know if I will be camping mostly in shade or full sun or if I will spend most of my time at sites with shore power or not. I am going to do it because I want to. I am a tinkerer. I like gadgets. But I also hunt in areas with no power and I plan on doing more fishing trips into areas which might not have power. I am also an engineer by training and am going to add solar water panels for this winter's heating needs. Thus all of this fooling around, all of this self-teaching and reading all I can on the topic also prepares me for the work when I start it. All of these posts by other trailer builders helps tremendously. I learn from other's experiences. All of these tendencies sort of explain why I am also fooling around with radiant heat tubes in my double layered floor.

[JaggedEdges]

It would occur to me that if you had your panels airgapped off the trailer, and had it pretty much covered in them you'd be making your own shade under them. Also good for the panels to run cooler I think. (If you wanna get really fancy you can rig the whole thing as a convection assisted "chimney" that draws air from under trailer, encouraging inflow from trailers shade footprint at ground level, coolest air around, pulls it over trailer sunward surfaces, cooling backs of panels, and exiting at high point on roof.)

I'd be pulling the panels apart and reassembling the cells into odd configurations though if I got my hands on them, like edge to the sun in an angle reflector, for older cells that are backside active... but then you have to balance each assembly and rig it to a 24 hour timer motor for azimuth tracking at least.

[Gunman9]

What type of battery are yall using for your solar systems?

[desertrat222]

2 interstate 250 amp hour 6V bats here. then run my 1500 watt inverter and 3.3 cu ft fridge from fri-sun when camping. thus far anyways.

[MtnDon]

What type of battery are yall using for your solar systems?

Two GC-2 size golf cart batteries similar to what desertrat222 has; in series for 12 VDC.

I chose those because we wanted to have the operation of out 12 VDC refrigerator well covered.

[Gunman9]

What type of battery are yall using for your solar systems?

Two GC-2 size golf cart batteries similar to what desertrat222 has; in series for 12 VDC.

I chose those because we wanted to have the operation of out 12 VDC refrigerator well covered.

The solar panel I bought is a 100w panel. I was thinking 1 deep cell battery would work? Guessing I'm wrong

[MtnDon]

I chose those because we wanted to have the operation of out 12 VDC refrigerator well covered.

Let me add to that first comment... I also chose the GC-2's because they are true deep cycle batteries. The 12 volt batteries that we see labeled as being deep cycle are better than a regular car battery (usually) but they are still not as robust as a golf cart battery.



What battery anyone needs is going to depend on how much power they need to use from a battery. There is also a balancing act between how much money to spend and how much weight to carry around and how often the batteries will need replacing. Sometimes one or more things has to give in favor of the other. For myself, I have used RV/Marine deep cycle batteries and have never had good performance for more than a couple of years. To me and my type of use it is better for me to use the golf cart batteries. YMMV.

[khigh]

I'm decidedly unfancy.

I use the $70 100ah marine batteries from Academy

Like I said earlier, though, I have kind of a dead spot in my useage - lights and fan - then jump jump to air conditioning. No fridge or water heater or such.

The microwave I might use for a few minutes on battery, but I'm not trying to cook meals in it. I'd only plan on going overnight without my generator. I don't even try for a full weekend.

[Gunman9]

Ya I'm using the solar panel for the water pump, some LED lights only for when I don't have shore or generator running and that's pretty much it and to charge a phone. So I think I'm just going to go with a deep cycle from advanced like I use for my trolling motors I would assume that would be enough. Also I picked up a Ground Bus Bar can I just mount that to anything and have the main ground attachment running to the battery?

[lrrowe]

I was confused about what batteries until (a) I started to digest what was written about them in this forum and (b) I read this book:
http://www.amazon.com/gp/product/096473 ... UTF8&psc=1.

I am on my third reading of it and each time pick up something new that I missed before. This was one purchase well worth the price.
So now I am going with 6V Golf Cart batteries. I am convinced that even though I will pay much more up front but over a period of time, I will be $$$ ahead.

I expect these batteries to last me until Lithium batteries have come down in price and the industry has resolved many of the negative issues. And my plans call for 100 to 200 W of solar panels to go along with them. But all in baby steps.