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Old 09-11-2014, 19:43   #1
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Solar Panels

Hi all...another question for all you experienced people...What is better, 3 solar panels of 80Watts, or 2 panels of 120Watts...Will I get more amps from 3 panels than 2 panels?
I am thinking that the amps per cell is approx. 8 and in series the voltage goes up so the amps will be 8 for the panel...with the panels connected in parallel the amps goes up...correct? so 3 panels should give more amps than 2 panels...
What am I missing here, it all seems mixed up to me!!
Thanks a lot to EVERYBODY! I read all the threads on my email everyday and I am gaining knowledge...My boat will be here is a few months...FINALLY!!!
Have a great night and a better tomorrow!

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Old 09-11-2014, 22:33   #2
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Re: Solar Panels

Watts is watts. In isolation from all other factors it doesn't matter.

"And all I ask is a merry yarn from a laughing fellow-rover
And quiet sleep and a sweet dream when the long trick's over."
John Masefield
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Old 09-11-2014, 22:49   #3
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Re: Solar Panels

The output of 3x80w or 2x120w panels will be very similar.

More panels of the same total wattage do better in conditions of isolated shadows. These conditions are common on a boat so the 3x80w will be slightly better all other things being equal.

However, because of losses around the frame etc the 3x80w option will be a bit larger in surface area with the same cell effeciency.

The difference in output between the two options is small so generally ease of mounting, getting the appropriate total size, and cost, are the important factors.

When looking at cost make sure you factor in shipping charges. Some couriers charge an extra insurance cost on glass panels above a certain size. So 2x120w can have a significantly higher delivery cost than 3x80w. This difference is easy to miss as the delivery costs are not usually shown on the website prices.

The flaw in your thinking is that the amps per cell is not constant it goes up a wattage increases (assuming the same Vmp). As Olorin says watts are watts. Fit the most watts you can squeeze in.
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Old 10-11-2014, 06:31   #4
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Re: Solar Panels

Excellent guys...thank you very much. Since I have no issues with mounting etc. I am going to go with the 3 panels. I may even up them to 100 or 120Watts...
I love CF...I am learning sooooo much because of all of YOU!!! Thanks again.
Be safe and happy...
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