Solar panels

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

Power ( watts ) = Volts * Amps.

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.

Greybeard,
Is that " volts x amps"?
Cheers

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 :)

Yeah mate..that makes sense...Cheers

"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?

"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).

Gday Mark,
Thats not what I wanted to hear but probably the sort of thing I need to hear...
Cheers

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"

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 . . .

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

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 . . .

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

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.

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 . . .

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.

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 . . .

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.

greybeard this is the only sandbox mainey is allowed to play in.

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 . . .

. . . . and if you had a few hours to spare, you could explain that amps and amphours are actually different measurements.

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!

Gday,
Duno????
What would you recomened?
Copper strips soldered to the cells was what I thought they did.

Cheers

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.

i can sell you a 30 kw dish for mates rates Hairy, wink wink

Handy,
Ya reckon it would fit on top of the car?

hahahaha