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Post by swbls12b on Sept 2, 2016 13:59:53 GMT -8
Looking at the 100watt panels and trying to decide if the benefits are worth the price difference?
space is not a factor as I live on 2 acres.
Just trying to decide if that bang is worth the extra bucks.
BTW, I am a total newb and ALL opinions are welcome.
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Post by jsb2000 on Sept 2, 2016 16:32:41 GMT -8
Looking at the 100watt panels and trying to decide if the benefits are worth the price difference? space is not a factor as I live on 2 acres. Just trying to decide if that bang is worth the extra bucks. BTW, I am a total newb and ALL opinions are welcome. In my opinion, all other things being equal, I'd say that the slight increase in efficiency and the aesthetics (Black trim, etc.) isn't worth the extra money. But that's me. Personally, a 2.88% difference in efficiency seems trivial. I don't care about the lack of trim lines "to allow for a more clean look." I'm not trying to win some sort of popularity contest with my solar installation versus someone else's. Black frame? Just serves to heat things up and would cause it to stand out like a sore thumb on my awning. |
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Post by rabird on Sept 2, 2016 16:33:09 GMT -8
I prefer poly so I ain't got no dog in that fight.
poly is generally cheaper so you can buy more watts which is what matters.
especially if space is not an issue.
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Post by swbls12b on Sept 2, 2016 18:13:34 GMT -8
I prefer poly so I ain't got no dog in that fight. poly is generally cheaper so you can buy more watts which is what matters. especially if space is not an issue. ALL input is welcome and appreciated. |
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Post by rabird on Sept 3, 2016 6:01:49 GMT -8
its the whole package not just one item, wire size/connectors, fuse(s), disconnects, controller (PWM/MPPT), application, panel(s) 12v/24v, mounting, sizing, ...
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Post by cosmicboss on Sept 12, 2016 10:57:46 GMT -8
I am with JSB2000 on the eclipse vs the regular 100 watt.
I am with Rabird with regards to the availability of mounting surfaces. Poly is cheaper, but larger in overall panel size. Mono is more expensive, but if mounting surfaces are at a premium then Mono takes up less space.
**edit: I prefer Mono though.
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Post by cosmicboss on Sept 12, 2016 11:02:41 GMT -8
Also, dumb statement, but for those who may think that mono is superior in energy production over poly... a 100w panel is just that, a 100w panel regardless of the material of the cells. 100w mono = 100w poly.
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Post by rabird on Sept 12, 2016 15:37:39 GMT -8
compare the 3 100 watt panels Renogy offers.
Panel, Isc, Imp
Eclipse, 6.1A, 5.7A
Polly, 5.92A, 5.62A
momo, 5.75A, 5.29A
if we assume @13v they all operate @ Isc amperage (IV curves unavailable).
eclipse 13v * 6.10A = 79.30 watts
polly 13v * 5.92A = 76.96
mono 13v * 5.75A = 74.75
if all things were EQUAL (they are not), using PWM, get the highest Isc!
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Post by jsb2000 on Sept 12, 2016 16:41:51 GMT -8
Being the (ahem...frugal...) cheapskate that I am, I look at the prices as well as the current and power ratings. So, my additions to rabird's excellent post in bold: compare the 3 100 watt panels Renogy offers. Panel, Isc, Imp, Current PriceEclipse, 6.1A, 5.7A, $219.99Polly, 5.92A, 5.62A, $144.99momo, 5.75A, 5.29A, $149.99if we assume @13v they all operate @ Isc amperage (IV curves unavailable). eclipse 13v * 6.10A = 79.30 watts or about $2.77 per wattpolly 13v * 5.92A = 76.96 or about $1.88 per wattmono 13v * 5.75A = 74.75 or about $2.01 per wattif all things were EQUAL (they are not), using PWM, get the highest Isc! Another way I'd look at it: Starting with the cheapest option (the Polly), am I going to spend an extra $75 for the Eclipse and get an extra measly 2.34 Watts? No way. Would I spend an extra $5 for a more efficient, heat tolerant, generally longer lived MONO panel at the cost of a measly 2.21 Watts? You betcha! So, it's MONO for this MANO.  |
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Post by cosmicboss on Sept 13, 2016 6:43:54 GMT -8
Just saying that at STC (standard testing conditions) they all produce about 100w. Which is why Renogy gets to slap a 100w label on the panels. Or else they would be getting sued for false advertisement and the reason for the existence of STC so that manufacturers don't pick and choose which numbers/stats to use to make their claims.
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Post by rabird on Sept 13, 2016 7:37:38 GMT -8
 Each panel has a specific iv/power curve. Note the power at zero volts, 5, 10, 20! PWM @ battery voltage is less than rated power. @stc mppt might harvest rated watts then looses some bucking. Also, as panel temp increases so does Isc (PWM), mppt peak power sure drops off!  Also note the temp coeff are identical for the 'Renogy' polly and mono  |
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Post by cosmicboss on Sept 13, 2016 9:15:17 GMT -8
I am not talking about charge controllers, or which of their technologies makes the panels deliver power more efficiently to the batteries or how temperature has a big influence on performance.
If you multiply Vmp (Optimum operating voltage) and Imp (Optimum operating current) for all the panels you compared, you get roughly 100W. That is all.
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Post by rabird on Sept 13, 2016 11:16:21 GMT -8
so what? panels don't operate @ Vmp with a PWM controller. Folks are surprised when they don't get 100 watts out of a 100 watt panel. or they divide 100/12 and expect 8A! Many consider them constant current so the one with the highest current wins! watch this as one hooks up a 20 watt bulb to a 21 watt panel, a perfect match = 6v, 1A !! www.youtube.com/watch?v=JZQEJ33xblE |
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Post by cosmicboss on Sept 13, 2016 11:48:50 GMT -8
Read the question again. The OP is not asking about controllers. He asking about the differences between a mono panel and a "black" mono panel with slightly better performance, and I just happen to add that a 100w poly is equivalent to 100w mono regardless of what temperature they are operating at, or what type of controller they are attached to.
A ton of cotton weights the same as a ton of steel. 100w is just a rating at standard (or controlled) conditions.
Yes, all of them have built in inefficiencies. From the panels, to the controllers, to the batteries, inverters... all the way down to the conductors! But that is not the question.
He will have to figure that out at a later point. He may decide to stick to the eclipse just because they are black or whatever other reason.
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Post by swbls12b on Sept 13, 2016 12:11:39 GMT -8
Thanks for all of the replies and great information.
As much as I would like to keep the footprint as small as possible,
I don't think I can justify the price difference.
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