Dream Solar system

[LK Gray]

No, actually the EVA is what binds the monocrystalline photovoltaic cells together and give the panel it's shape, flexibility & strength.
I'll get around to doing some homework one of these days and let all know what I find out.
LKG907

[Steve Hammel]

Hmmm, don't know for sure but since the nature of solar is to be in prolonged sunlight I'd assume the EVA would be designed for such use.

[Stretcher]

Do you know if Solar South is still in business? I emailed them a few days ago and left a couple of voice-mails and have had no response.

David

[Steve Hammel]

Has anyone tried those ultra thin Unisolar roofing laminates from Solar Blvd? They look interesting.

[Stretcher]

Originally Posted by Stretcher

Do you know if Solar South is still in business? I emailed them a few days ago and left a couple of voice-mails and have had no response.

I got the answer to my own question. Mark from Solar South called today and was very straightforward and informative. He had been traveling and unable to respond to my questions. Seems like a good guy. I plan to order two 40-watt panels and a 15 amp controller for my Scamp 5er.
David

[Steve Hammel]

What is the minimum strength that a system should have and over what strength would be a waste of time for a camper. I've been on ebay and there are about 600 plus pages of good deals. Some come with chargers most don't. The chargers are mostly between 10 and 30 amps. It appears a 10 amp will easily handle up to 150 watt panel, but the 20 or 30 amp controlers look nicer and have more features for just a few dollars more.

[multi-task]

As a general rule, most solar forums will tell you to have a minimum of one watt per amp hour of battery capacity, with many recommending more which is often difficult with a trailer due to space constraints, and cost. Then you would size your controller based on that. Keep in mind good deals don`t always equal good quality. Panel efficiency on good deals tend to be terrible so it`s important to ignore STC ratings and look at NOCT ratings. A good panel will have a small watt difference with a bad panel having a large watt difference. A good manufacturer will list them on the spec sheet.

I inherited a 75w Siemens (Shell) panel which rarely ever reaches it`s STC rating unless conditions are perfect, which is hardly the case while camping. Because of that I upgraded to a Morningstar mppt controler and I`ll be adding a high voltage panel in the spring, but my needs are to never ever plug in. Usage is key, if you know what you draw then you can size based on that which might be a lot less than the recommended amount.

Controllers boil down to amp capacity to support or grow your array, then pwm or mppt. If you go high voltage you need mppt, if not pwm is most likely the way to go. And of course cost, everyone has a different budget

[Steve Hammel]

Good Info! I'm such a novice when it comes to solar. I was reading some of the ad info and what appeared to be the better/most expensive panels listed "efficiency rates". Surprisingly these went from 14% up to 19%. To me this was quite shocking as I expected better. The cheaper units didn't even bother to list their efficiency rates. I also hear that there is a huge difference in efficiency between the MPPT and PWM controllers with the MPPT being superior. What is the key thing I should look for in a decent panel? I am going with 2 6v deep cycle batteries (like what Costco or Sams Club sells). I will be installing Led lights inside but I'm also leaning to a 12v high efficiency compressor refigerator. I rarely go more than 3 days w/o being plugged in somewhere for a night.

[honda03842]

Steve, It's hard to beat a propane based refrigerator. They are expensive but great for boondocking. If you add an electric fridge I'm sure it will be your biggest user of electricity no matter it's efficiency. How efficient is it?

In reality we find we use very little electric power when off the grid between the TV, Sat Dish, LED lighting, Wi-fi hotspot, computer charging and water pump. Certainly the water pump is the biggest instanteneous drain.

[multi-task]

Steve, my setup is almost exactly what you described. I use a novakool fridge, it draws around 2 amps when running, nothing when not. Charging under load is something I’ve monitored. Using a Trimetric I’ve seen an average charge of 2-3 amps go into negative territory when the compressor kicks in. This causes the voltage to drop then climb back up when the fridge turns off. The voltage yo-yo is terrible for charging as you need to keep a constant voltage for long enough to actually charge the battery. So my recommendation is to have a panel/controller combo to negate any common loads (like a fridge not a stereo) while charging, but only if it meets your budget.

MPPT is a winner when the panel voltage is much greater than the battery voltage. With my current setup I’ve never seen a bonus, but I have seen my panel hit it’s STC rating which I’m not convinced would happen with a PWM controller. My goal is to go high voltage, if not I might have considered a higher quality PWM controller as they aren’t expensive.

Here is a long article which explains panel efficiencies, well worth the read: Photovoltaics Modules 101 from Sunlight Electric

[Steve Hammel]

Honda, the 12v fridge I'm talking about is even more expensive than a 3 way. However they are ultra efficient, keep things much colder, don't need leveling, and get cold faster. These aren't dorm fridges tied to an inverter like some people use. I had one in my Trillium and LOVED it. The only problem is the biggest I found is a 2.7 and I want one a bit bigger.

[itlives]

I just checked the specs on the Novacool fridges. They use 2.5A @ 12V. That is very good and comparable to Engel fridges which (if you ask me) are the top of the line.
I sold my Engel with my last vehicle (wish I hadn't)!
FYI- I replaced the Engel with a Chinese Whynter fridge. The FYI is ALL the Whynter ads say their fridges use 2.75A @ 12V ,which would be great, but they actually use 5.8A @ 12V. Now, when you put together a small solar system, that is a huge draw!
I have brought this to the attention of Whynter LLC. but they have yet to change their ads. I would NOT buy a Whynter fridge if you'll be using it on a small system.
The problem is compounded by the fact that the sellers on Ebay just copy/paste from the Whynter website, perpetuating the flase info.
I would buy the Novacool with it's low amperage use!
I would buy this (if it will fit)-
Engel SB70F DC Only 12V Front-Open Fridge 60 Quart | eBay
I use the chest type like this- I like the chest type because it doesn't lose the cold when you open it.

[Steve Hammel]

I would consider the chest type in addition to the regular but not as a stand alone fridge. I believe this is the Norcold/Thetford model that I had. It uses 2.5 to 3.1 amps.







Model Height Width Depth DC-0051 20-1/2": 520.7 mm 18-1/2": 469.9 mm 21": 533.4 mm Model Interior Volume Net Weight Shipping Weight DC-0051 2.7 cu.ft.: .82 cu.m.
49 lbs.: 22 kg. 58 lbs.: 26 kg.

Door Panel Dimensions
Model Height Width Thickness DC-0051 16-1/2": 419.1 mm 17-1/8": 434.9 mm 3/16": 4.8 mm
Power Source
Model Amps 12-24V/DC DC-0051 2.5-3.1

[multi-task]

I can vouch for nova kool, it runs at or better than spec and it`s from 2004. Mine is quite small, I think around 2.1 cubic feet. At 12v it`s stamped to run at 2.2 amps but runs closer to 2 which was a nice surprise.

[honda03842]

What is the duty cycle of the 2.5 amp current draw? What percentage of the time does the cooling cycle run?

[Steve Hammel]

Norm,
I can't say, would have to research that as it would depend on outside temps, etc. I will say that I was getting 2 to 3 days off grid with a single old 12v battery with no solar, generator, etc. I was in 50-60 degree temps at Ocean Shores Washington rather than in the heat of the desert. Essentially, other than 1 light sometimes, it was the only appliance I had. I'm sure with 2 healthy batteries and an adequete solar system one should be able to go indefinately. I believe Egg campers makes an all electric version, they may be able to supply you with their research.

[Stretcher]

Originally Posted by Steve Hammel

Good Info! I'm such a novice when it comes to solar. I was reading some of the ad info and what appeared to be the better/most expensive panels listed "efficiency rates". Surprisingly these went from 14% up to 19%. To me this was quite shocking as I expected better. The cheaper units didn't even bother to list their efficiency rates. I also hear that there is a huge difference in efficiency between the MPPT and PWM controllers with the MPPT being superior. What is the key thing I should look for in a decent panel? I am going with 2 6v deep cycle batteries (like what Costco or Sams Club sells). I will be installing Led lights inside but I'm also leaning to a 12v high efficiency compressor refigerator. I rarely go more than 3 days w/o being plugged in somewhere for a night.

Where/how do you plan to mount the two batteries on your 5er?

[Steve Hammel]

I'm going to mount them in the front by the landing gear where the newer Scamp 19's have built that shelf to hold the battery and propane tanks. I will go to one tank. I have the original 20 tanks but I also have 30's and 40's if I need more capacity.