Solar panels

Submitted: Sunday, Feb 15, 2009 at 13:02
ThreadID: 66000 Views:2646 Replies:6 FollowUps:27
This Thread has been Archived
Gday,
Has anyone had any expierience in building your own solar panels?
Ive noticed you can buy all the parts to build your own for about half the price as a complete panel.
Can anyone recomend a type of kit and where to get one or any info good or bad about building one?

36 SOLAR CELLS - 5" X 5" -.5 VOLT, 4 AMPS , 2 WATTS
For around $250 including tape, feedback diode and a few other bits.

Cheers
Hairy
Back Expand Un-Read 0 Moderator

Reply By: MEMBER - Darian (SA) - Sunday, Feb 15, 2009 at 14:08

Sunday, Feb 15, 2009 at 14:08
Reliability and durability of the finished product might be the big issue in home built panels ...... assembly and finish are really big factors in commercial products that are guaranteed for 20 odd years !
AnswerID: 349182

Follow Up By: Hairy (NT) - Sunday, Feb 15, 2009 at 15:06

Sunday, Feb 15, 2009 at 15:06
Gday,
Wouldnt that just come down to good soldered joints and a strong enough frame?
I was thinking toughened laminated glass top with an acrylic back and an aluminium edge?

Cheers
0
FollowupID: 617422

Reply By: Member Brian (Gold Coast) - Sunday, Feb 15, 2009 at 15:28

Sunday, Feb 15, 2009 at 15:28
Hairy,
I can't answer your question from a technical viewpoint, but I am interested in it. Not for myeself, I have a panel, but there are others I know that may want one. Keep us posted if you go ahead with it...

Cheers

Brian
AnswerID: 349204

Reply By: Hairy (NT) - Sunday, Feb 15, 2009 at 16:14

Sunday, Feb 15, 2009 at 16:14
Gday,
Heres another question or 3............
My current panel is a BP, 46 watt panel, so Id like to produce another 60 odd watts.
How do I measure watts??? My multimeter only has amps and volts on it as far as I know?
How many amps (roughly) do I need for charging a 12 volt battery running a 60lt Waeco and a light or stereo etc.
I know there are a lot of variables, Im just trying to get an idea of what size panel I need to make?

Cheers
AnswerID: 349213

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 17:07

Sunday, Feb 15, 2009 at 17:07
Power ( watts ) = Volts * Amps.
0
FollowupID: 617444

Follow Up By: Member - 1/2A - Sunday, Feb 15, 2009 at 17:14

Sunday, Feb 15, 2009 at 17:14
To Run a fridge and charge a battery in hotter climates (40+) you need about 150 watts. I run a fridge and a freezer using 150 watts but have Bushman fridges that use a lot less power than the Waeco. The SIL has a 60lt Waeco and we often go away together so I know no know exactly the consumptions between the two as we both have Xantrrex battery monitors and the same AGM battery setup.
0
FollowupID: 617446

Follow Up By: Hairy (NT) - Sunday, Feb 15, 2009 at 22:41

Sunday, Feb 15, 2009 at 22:41
Greybeard,
Is that " volts x amps"?
Cheers
0
FollowupID: 617540

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 22:50

Sunday, Feb 15, 2009 at 22:50
yes hairy, if you measure the voltage with the load connected and the current with the power connected and multiply the two figures together you get power.
ie. say 12 volts and 2 amps = 12*2 = 24watts
clear as mud :)
0
FollowupID: 617543

Follow Up By: Hairy (NT) - Sunday, Feb 15, 2009 at 22:56

Sunday, Feb 15, 2009 at 22:56
Yeah mate..that makes sense...Cheers
0
FollowupID: 617548

Follow Up By: paulnsw - Monday, Feb 16, 2009 at 07:41

Monday, Feb 16, 2009 at 07:41
"Bushman fridges that use a lot less power than the Waeco" ROFLOL LOL LOL
same compressor as a Waeco and same thickness insulation and uses less power LOL LOL LOL LOL ROFLOL
where do you hear that rubbish from?
0
FollowupID: 617578

Follow Up By: Member - Mike DID - Monday, Feb 16, 2009 at 09:45

Monday, Feb 16, 2009 at 09:45
"yes hairy, if you measure the voltage with the load connected and the current with the power connected and multiply the two figures together you get power.
ie. say 12 volts and 2 amps = 12*2 = 24watts "

That's logical, but that's NOT the way the ratings on ALL commercial solar panels are determined - surprisingly they use a method that gives a much higher number.

They indicate the maximum power you can EVER get out of a panel, but not when charging a 12 volt battery.

The current from them is fairly constant up to about 18 volts - so they calculate power by using amps x 18 volts (for a "12" volt panel).
0
FollowupID: 617592

Reply By: Lucko - Sunday, Feb 15, 2009 at 16:18

Sunday, Feb 15, 2009 at 16:18
Hairy,
Without wanting to rain on your parade, solar panel construction is a very specialized art. For example, the glass cover on modern panels is not only high strength but low in Iron which allows a more efficient passage of solar energy. Very important when you consider that even modern monocrystalline panels are only 14 - 17% efficient. Small issues like this have a significant impact on panel output. That glass, on good quality panels, can also withstand things like hail at incredible velocity.
I've seen these kits, but to be honest IMHO, they are meant more for the experimenter rather than campers etc. who really need something that's bullet proof.
Mark
AnswerID: 349214

Follow Up By: Hairy (NT) - Sunday, Feb 15, 2009 at 16:26

Sunday, Feb 15, 2009 at 16:26
Gday Mark,
Thats not what I wanted to hear but probably the sort of thing I need to hear...
Cheers
0
FollowupID: 617437

Reply By: Maîneÿ (wa) has - Sunday, Feb 15, 2009 at 18:33

Sunday, Feb 15, 2009 at 18:33
" .5 VOLT - 4 AMPS - 2 WATTS for around $250"

Looks like a very expensive solar panel
when you can get:
17 Volt - 7 Amp - 120 Watt panel for ~$999 with a warranty

Any ½ Volt panel will be a bit inefficient with a 12v battery too.

Mainey . . .


AnswerID: 349245

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 19:52

Sunday, Feb 15, 2009 at 19:52
might make a little more sense if you read the entire thread from the beginning.
"36 SOLAR CELLS - 5" X 5" -.5 VOLT, 4 AMPS , 2 WATTS"
0
FollowupID: 617490

Follow Up By: Maîneÿ (wa) has - Sunday, Feb 15, 2009 at 20:27

Sunday, Feb 15, 2009 at 20:27
36 solar cells, each is 5 inch square

Each is: ½ Volt, 4 Amps & 2 Watts ?

O.5 Volts x 4 Amps = 2 Watts, which shows correct specifications.

36 cells x 0.5v = 18v (correct for 12v battery)
36 cells x 2 Watts = 72 Watts (logical number)
72 Watts / 18 Volts = 4 Amps

If one cell is: 2 Watts, why is 36 only 4 Amps ??

Mainey . . .



0
FollowupID: 617495

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 21:20

Sunday, Feb 15, 2009 at 21:20
because you connect them in series.
36 cells @ 0.5V per cell in series -> 36* 0.5V = 18V @ 4 amps -> 18v * 4A = 72W

36 cells @ 0.5V per cell in parallel -> 36 * 4 A = 0.5V @ 144 amps -> 0.5V * 144A = 72W

36 cells @ 2W per cell -> 36 * 2W = 72W

there is a fixed relationship between voltage, current and power.
series connection of like devices means the voltage adds up and the current remains the same.
parallel connection of like devices means the voltage stays the same and the current adds up.
this applies to batteries as well as solar panels.

if you wish to understand this you need to understand basic electricity and apply those principals in full to any calculation.


if you do not understand this relationship
0
FollowupID: 617506

Follow Up By: Maîneÿ (wa) has - Sunday, Feb 15, 2009 at 22:28

Sunday, Feb 15, 2009 at 22:28
Yes, as I understand it:

*Series* -> Voltage increase - 36 x 0.5v = 18 Volts
*Parallel* -> Amps increase - 36 x 2w = 72 Watts


You say:
36 cells @ 0.5V per cell in parallel
36 x 4 Amp = 0.5V @ 144 amps <<<- 4 Amps ???
0.5V x 144A = 72W

BUT .. where do you get the 4 Amps from ?
please type slowly cause I can't read fast

Mainey . . .
0
FollowupID: 617530

Follow Up By: Hairy (NT) - Sunday, Feb 15, 2009 at 22:39

Sunday, Feb 15, 2009 at 22:39
So.....
You both lost me?
What was the question again???


Are you saying...you cant make GOOD panel cheaper than you can buy one or what?

LOL
0
FollowupID: 617536

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 22:40

Sunday, Feb 15, 2009 at 22:40
the 4 amps came from the sun and it is the specification quoted per cell as stated in the first post and on every single post you have made.

W = watts
V = volts
A = amps.

volts volts
volts watts

you'll stop confusing youself if you take the time to understand the laws of electricity and take the time to look at what you are saying and don't keep translating between different measurements

you also haven't understood or read the explanation of the implications of connecting generators in series or parallel.

neither you nor I can change the laws of electricity.
try a google on series /parallel electrical connections. it might convince you that one of us has a differing view than the rest of the world.
0
FollowupID: 617537

Follow Up By: Maîneÿ (wa) has - Sunday, Feb 15, 2009 at 22:43

Sunday, Feb 15, 2009 at 22:43
well I reread it slower, your numbers are as I've posted above
Solar panels are wired in SERIES

My post states:
36 solar cells each: ½ Volt, 4 Amp & 2 Watt
0.5 Volt x 4 Amp = 2 Watts
36 cells x 0.5v = 18v (correct for 12v battery)
36 cells x 2 Watt = 72 Watt
72 Watt / 18 Volt = 4 Amp

Mainey . . .

0
FollowupID: 617541

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 22:46

Sunday, Feb 15, 2009 at 22:46
mainey this is what you stated
*Series* -> Voltage increase [correct]- 36 x 0.5v = 18 Volts [correct]
*Parallel* -> Amps increase [correct]- 36 x 2w = 72 Watts[***** WRONG WRONG WRONG *****]

it's almost correct apart from the incorrect formula where you seem to think watts = amps

so
*Series* -> Voltage increase - 36 x 0.5v = 18 Volts
*Series* -> Watts increase - 36 x 2w = 72 Watts

*Parallel* -> Amps increase - 36 x 4A = 144 amps
*Parallel* -> Watts increase - 36 x 2w = 72 Watts

the total power is the sum of all of the indivdual powers. ther is no difference in total power if you connect the cells in series or parallel.
0
FollowupID: 617542

Follow Up By: Maîneÿ (wa) has - Sunday, Feb 15, 2009 at 22:53

Sunday, Feb 15, 2009 at 22:53
you post:
so
*Series* -> Watts increase - 36 x 2w = 72 Watts

how does that differentiate from what I posted:
" 36 cells x 2 Watt = 72 Watt "
remember type slowly please

Mainey . . .
0
FollowupID: 617547

Follow Up By: greybeard - Sunday, Feb 15, 2009 at 22:56

Sunday, Feb 15, 2009 at 22:56
find someone else to play with mainey.
i'm not sure what you find entertaining about taking, even your own, replies out of context.
this is a waste of time.
0
FollowupID: 617549

Follow Up By: paulnsw - Monday, Feb 16, 2009 at 07:46

Monday, Feb 16, 2009 at 07:46
greybeard this is the only sandbox mainey is allowed to play in.
0
FollowupID: 617579

Follow Up By: Maîneÿ (wa) has - Monday, Feb 16, 2009 at 09:22

Monday, Feb 16, 2009 at 09:22
Paul,
I choose to pay my fee's as a 'Member' here because I believe the EO "Forum" is definitely N0T a 'sandbox' as you have labelled it.

Mainey . . .

0
FollowupID: 617589

Follow Up By: Member - Mike DID - Monday, Feb 16, 2009 at 09:52

Monday, Feb 16, 2009 at 09:52
. . . . and if you had a few hours to spare, you could explain that amps and amphours are actually different measurements.
0
FollowupID: 617593

Follow Up By: Boobook2 - Wednesday, Feb 18, 2009 at 09:23

Wednesday, Feb 18, 2009 at 09:23
Noooooooooo..... Geesus Mike, I still have a headache from that one. Too much hitting against a brick wall. Though I must admit that this thread is starting to look similar. Doh!
0
FollowupID: 617875

Reply By: Member - Mike DID - Sunday, Feb 15, 2009 at 19:16

Sunday, Feb 15, 2009 at 19:16
Thermal expansion and contraction as the panel heats between full sunlight and frosty nights will produce huge mechanical stresses - how will you do the wiring to keep it reliable ?
AnswerID: 349254

Follow Up By: Hairy (NT) - Sunday, Feb 15, 2009 at 22:36

Sunday, Feb 15, 2009 at 22:36
Gday,
Duno????
What would you recomened?
Copper strips soldered to the cells was what I thought they did.

Cheers
0
FollowupID: 617534

Follow Up By: Member - Mike DID - Monday, Feb 16, 2009 at 09:54

Monday, Feb 16, 2009 at 09:54
There are certain alloys available (e.g. Invar) which have minimal thermal expansion - although you actually want something that has the same coefficient of expansion as the base material.

One principle is not to have straight links - the bends can then absorb the movement.
0
FollowupID: 617594

Follow Up By: handy - Monday, Feb 16, 2009 at 12:48

Monday, Feb 16, 2009 at 12:48
i can sell you a 30 kw dish for mates rates Hairy, wink wink
0
FollowupID: 617614

Follow Up By: Hairy (NT) - Wednesday, Feb 18, 2009 at 16:28

Wednesday, Feb 18, 2009 at 16:28
Handy,
Ya reckon it would fit on top of the car?

hahahaha
0
FollowupID: 617941

Sponsored Links

Popular Products (14)