Solar Panel sizing

G'day solar panel experts. I am looking at some solar panels on ebay, the 120W ones are exactly the same dimensions as the 100W ones. The 80W ones are only 3/4 the size.

My question is, why would the 120W and the 100W, which are physically the same size, the same number of cells, etc, and almost the same rated efficiency (16.9% vs 16.5%), have a different output? Are the 100W ones just downrated with a smaller regulator? Is there something I am missing here? Should I save myself $100 and just buy the 100W ones?

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Reply By: greybeard - Sunday, Feb 07, 2010 at 01:26

Sunday, Feb 07, 2010 at 01:26
this might give you some ideas panel sizing
AnswerID: 403026

Reply By: Member - Ed C (QLD) - Sunday, Feb 07, 2010 at 01:47

Sunday, Feb 07, 2010 at 01:47
Can you put up links to the ones you're looking at ?

There is one ebay seller in particular (that we know about) who has a known history of supplying under-sized/over-specced panels... e.g., buy a 120W folding kit and receive a 100W kit (if you're lucky) or a 80W kit w/- a 120W-spec sticker on it... This has happened to a few folk on this forum that I'm aware of, including myself :(

If/when challenged, he'll 'make good', but there must be a lot of people out there who have solar panels which are not what the sticker on the back purports them to be:(

Buyer Beware !!

:)



Confucius say.....
"He who lie underneath automobile with tool in hand,
....Not necessarily mechanic!!"

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AnswerID: 403028

Follow Up By: Ti Trol - Sunday, Feb 07, 2010 at 09:04

Follow Up By: Member - Ed C (QLD) - Sunday, Feb 07, 2010 at 12:13

Sunday, Feb 07, 2010 at 12:13
G'day Ti,
Well, the good news is that it's not the seller to whom I was referring :)

I offer no comment on the panels, except to say that when the freight cost is taken into account, there are better deals to be had..

May I suggest that you have a look at the offerings from seller ' bit_deals ' This seller is apparently the Aust distributor for Rich Solar (mentioned below), and one of the better ebay sellers (the item you receive will be what is described in the listing:))

Alternatively, you may wish to have a chat to Mandrake on the forum here ;-)

:)
Confucius say.....
"He who lie underneath automobile with tool in hand,
....Not necessarily mechanic!!"

Member
My Profile  Send Message

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FollowupID: 672572

Follow Up By: trainslux - Sunday, Feb 07, 2010 at 15:11

Sunday, Feb 07, 2010 at 15:11
Hi Ed,
Cant find your email, if you still have mine, can you send one thru.
cheers

Trains
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FollowupID: 672599

Reply By: Maîneÿ . . .- Sunday, Feb 07, 2010 at 10:45

Sunday, Feb 07, 2010 at 10:45
I would not consider that supplier, as they don't give relevant information that can be varified to be true and correct.

There are suppliers on here that will give you quality panels at reasonable prices.

Maîneÿ . . .
AnswerID: 403069

Follow Up By: Injected - Sunday, Feb 07, 2010 at 11:15

Sunday, Feb 07, 2010 at 11:15
Mainey....
Who would you recommend then? Some people say RICH brand panels. All very confusing these days....If only the world was full of honest resellers it would be easier. I know that your imput to the site is highly regarded.
Cheers
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FollowupID: 672563

Follow Up By: Maîneÿ . . .- Sunday, Feb 07, 2010 at 11:22

Sunday, Feb 07, 2010 at 11:22
I recomend the RICH brand panels :-)

(not connected in any way with them)

Maîneÿ . . .
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FollowupID: 672565

Follow Up By: Member - Boobook - Monday, Feb 08, 2010 at 06:31

Monday, Feb 08, 2010 at 06:31
Mainey the specs are all there. Down the bottom of the page.

from website
.............................

The spec. is for one Monocrystalline 60W solar panel:


TYPE

60 Watts
Solar cell

Mono
Maximum power (Wp)

60.00
Maximum power voltage (V)

18.00
Maximum power current (A)

3.33
Open circuit voltage (V)

21.60
Short circuit current (A)

3.59
Cell Efficiency (%)

16.90%
Number of cells (Pcs)

72(4*18)
Size of module (mm)

810*534*35
Maximum system voltage (V)

1000V
Temperature coefficients of Isc (%)

0.03%/?
Temperature coefficients of Voc (%)

-2.2mV/?
Temperature coefficients of Pm (%)

-0.55%/?
Temperature coefficients of Im (%)

0.03%/?
Temperature coefficients of Vm (%)

-2.2mV/?
TemperatureRange

'-40C------+85C
Surface Maximum Load Capacity

60m/s(200kg/sq.m)
Allowable Hail Load

steel ball fall down from 1m
Weight per piece (kg)

6.50
Output tolerance (%)

±3%
Frame (Material, Corners, etc.)

Aluminum
Standard Test Conditions

1000W/m2 AM1.5 25’C
FF (%)

=74%
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FollowupID: 672686

Reply By: trainslux - Sunday, Feb 07, 2010 at 13:20

Sunday, Feb 07, 2010 at 13:20
With the current ebay panels, there are some 100w units in the same physical size as the 120s.
The 100s have smaller solar cells on them, and the spacing is further apart, the 120s are larger cells, and little gap between them.
No idea why, just the way they come from the factory.

hope that answers your question.

Trains
AnswerID: 403095

Follow Up By: Ti Trol - Sunday, Feb 07, 2010 at 20:25

Sunday, Feb 07, 2010 at 20:25
Thanks Trains, this makes sense (in a mathematical way if not logical). I will make another enquiry from the vendor.

Cheers
0
FollowupID: 672647

Reply By: Member - Christopher P (NSW) - Sunday, Feb 07, 2010 at 22:16

Sunday, Feb 07, 2010 at 22:16
Also check out solaronline. good guys and they go the extra distance
AnswerID: 403184

Reply By: Maîneÿ . . .- Monday, Feb 08, 2010 at 02:19

Monday, Feb 08, 2010 at 02:19
Ask who will honour the product *quality* warranty
(not the 25 year performance warranty)

I would want to know who the manufacturer is and the model number of the panel before I paid for something that looks like it could be a bit sus, well you have asked the question, so your not entirely sure it is not sus.

The numbers have nothing at all to do with the regulator, and make sure the supplied regulator is NOT attached under either of the panels, place it on or beside your battery.

Maîneÿ . . .
AnswerID: 403206

Follow Up By: Ruffstuff. - Tuesday, Feb 16, 2010 at 14:35

Tuesday, Feb 16, 2010 at 14:35
"make sure the supplied regulator is NOT attached under either of the panels, place it on or beside your battery"

Hi Mainey,
Whats the reason for this?
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FollowupID: 674105

Follow Up By: Maîneÿ . . .- Tuesday, Feb 16, 2010 at 15:21

Tuesday, Feb 16, 2010 at 15:21
Having Regulator situated beside the battery keeps it out of the rain and weather and it *regulates* the current recieved at *the far end* of the power cable near the battery.

If the reg is attached to the panel it regulates the current back up there, the current going into the battery will be less due to any loss in the cables going down to the battery, therefore it's wasting power.

Maîneÿ . . .
0
FollowupID: 674113

Follow Up By: Ruffstuff. - Tuesday, Feb 16, 2010 at 16:27

Tuesday, Feb 16, 2010 at 16:27
Thanks for your insight, thats some valuable information i hadnt previously considered
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FollowupID: 674122

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