Solar Panel Differences?? Teach Me!!

jdholder

Explorer
So - I have a location where I can fit either of these solar panels (but not anything larger), but just wondering, why is there a big discrepencey between the two specs of these units? They are approximately the same size - I am a newb on this stuff, so and help is appreciated - but I always though size was important in solar panels.

This HQRP one is (47x21 inches): "80 watts" - Maximum Power Voltage: 17.6V; Open Circuit Voltage: 21.8V; Maximum Power Current: 4.83A - [ame="http://www.amazon.com/HQRP-Mono-crystalline-Anodized-Aluminum-Coaster/dp/B002OSAB28/ref=sr_1_21?ie=UTF8&s=hi&qid=1283881003&sr=8-21"]CLICK HERE[/ame]

and this Bruton one is (42x15 inches): # "15 Watts" - Output Voltage: 12V; Maximum Power Current: 1000mA: [ame="http://www.amazon.com/Brunton-Solarflat-15-Solar-Amorphous-Protection/dp/B001NG0WVW/ref=sr_1_10?ie=UTF8&s=electronics&qid=1283881441&sr=8-10"]CLICK HERE[/ame]

So - why the big different in specs?

I am looking to run a Engel MT040. I have two small (space issues) 35AH batteries that I want to keep charged via solar.

Thanks for your help!
 

Corey

OverCamping Specialist
Solar can be quite confusing.
I have a thread in this section on my installation from last year.

I went with a 60 watt panel on the recommendation of Martyn at Adventure Trailers, also where I bought my panel and cables from.

I use mine to keep the stock battery charged up while running the ARB fridge and the tents 12v light.

60 watts is also enough that it could power the fridge all by itself if the panel was getting full sunlight, but I bought the panel to just keep the batteries charged full all the time.

There should be lots of informative threads in this section.
 

jdholder

Explorer
Right, but I can't fit the 60 watt panel that AT sells! I need to know about these two.

How can two panels of approximately the same size produce far different specifications?

Also, why is one 50% of the other in cost? I imagine the higher cost one uses a different technology that improves power generation, but is it real? Or just smoke and mirrors from flawed testing, or marketing hype?

Thanks!
 

dzzz

http://sunelec.com/index.php?main_page=index&cPath=5&page=1&sort=3a

Picking obscure items from amazon and asking about prices isn't asking an answerable question. Or rather the answer is that they cost what they do because that's what the seller decided.
The link above is to Sun Electronics, a major discounter. All the panels they sell are from major suppliers. Pick a panel with a Vmp of 15-18, pick an appropriate size inexpensive Morningstar or Blue Sky controller, talk to the vendor about wire and mounting and you're done. (Blue Sky you would need to buy elsewhere).
 
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UK4X4

Expedition Leader
Solar panels.....I spec and use panels at work for remote monitoring stations

1 there are many technologies
2 china does not make reliable or efficient panels
3 stick to the major manufacturers BP/Shell/TOTal (all oil companies but also manufacture panels)

more watts per size usually means a higher spec and higher cost.

Bruton make camping gear, their solar stuff is just a sideline

Buy once buy right, I have installs coming up to 10 years old functioning fine with zero input.

here's a site with good prices and no odd name panels, good quality- you have to pay for !


If a big name professional company makes a 60w in 0.5 meters square for example

and kyyusun kitchen ware and solar inc china has a 150w with the same dimensions.........buyer beware !
 

jdholder

Explorer
Solar panels.....I spec and use panels at work for remote monitoring stations

1 there are many technologies
2 china does not make reliable or efficient panels
3 stick to the major manufacturers BP/Shell/TOTal (all oil companies but also manufacture panels)

more watts per size usually means a higher spec and higher cost.

Bruton make camping gear, their solar stuff is just a sideline

Buy once buy right, I have installs coming up to 10 years old functioning fine with zero input.

here's a site with good prices and no odd name panels, good quality- you have to pay for !


If a big name professional company makes a 60w in 0.5 meters square for example

and kyyusun kitchen ware and solar inc china has a 150w with the same dimensions.........buyer beware !

There wasn't a link in your message - what is the site with good prices and no off name panels?
 

jkam

nomadic man
Of the 2 you mention, the Brunton won't do much more than trickle charge your batteries. It doesn't have enough power to run the Engel.

Big difference between 80 watt and 15 watt panels, even though similar in size.

What is the size of the space you have available? With that, I can help better with a panel.

Also, might want to consider some of the portable suitcase style panels out there now.
80 watt ones are priced pretty reasonable and include a charge controller.
Many to choose from, most made in China so have to be careful on the quality.
Able to be placed where the sun is without having your rig in the sun.
Portable-solar-panel.jpg
 
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Xterabl

Adventurer
crystalline silicon (c-Si) vs. amorphous thin film silicon (a-Si TFPV): much higher watts per unit area is the difference you're seeing.
For mobile application, you pretty much want to stick with c-Si since space is at a premium. Some people like the roll-up CIGS cells which fall somewhere in between c-Si and a-Si...but price is quite high.
Sanyo, Kyocera, Sharp are some of the best c-Si panels, though they do not make very low-wattage panels...maybe 40W at a minimum? Yeah, check for Kyocera KC40T...it's a pricey but high-quality panel..$200-$300.
Also, better panels will have better weather sealing and less power drop over the life of the cell compared to most Chinese manufactured panels.
Having said all that, do your DD...I suggest at least a few hours research for every $100 you plan to spend.
Good luck!
 

jdholder

Explorer
Alright - did a bunch of research today and realized I needed help. Called the nice people at Sun Electronics and for the space I have available, this was the best of the bunch: CLICK HERE

Here are the specs:
Model SUN-75
Power (W) 75 Watts
Open Circuit Voltage (V) 21.70 Voc
Short Circuit Current (A) 4.89 Isc
Maximum Power Voltage (V) 17.10 Vmp
Maximum Power Current (A) 4.38 Imp
Dimensions 47 1/4" x 21 3/4" x 1 3/8"


The space I have is 49 x 22 x 2 - so this panel fits almost perfectly!

Thanks for all the help!
 

UK4X4

Expedition Leader
get them to explain to you what B grade is......

and what the warrentee is, BP for example is 25 years !
 
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jdholder

Explorer
get them to explain to you what B grade is......

and what the warrentee is, BP for example is 25 years !

I was told they have "cosmetic blemishes that do not affect power production" and have been tested to confirm that.

I forgot to ask about warranty. I'll call when they open.

Thanks!
 

Martyn

Supporting Sponsor, Overland Certified OC0018
Our experience with solid panels is that the actual panels themselves can be identical or close to identical in manufacturing and output, but the framework that they are built into varies.

For static locations this may not be an issue but for mobile applications a weak frame can spell disaster. We ended up using the Carmanah brand primarily because they came in a stout durable frame that could take the abuse of off-road travel and multiple set ups. We were also able to customize the frame to accept a stand.

The Carmanah panels suffered a lot of abuse from people over the years, they were dropped, stood on, and cracked, but kept working.

It's the durability issue again. Do you pay for something once or multiple times? May be more concerning do you save some money on the initial purchase only to have it fail at a remote location.
 

jdholder

Explorer
Thanks Martyn - I agree.

In my application, the panel will actually be placed into a metal framework and mounted to my roof rack. The framework will increase the protection to the panel (I hope).

I'm trying not to have that old adage apply to me: "Why is there never enough time (or money) to do it right the first time, but always enough time (and money) to do it over again?"
 
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