HS...Thanks...but I am still confused about your revised statement which said:
""That would be...about 250 Watt-hours up here, based on four hours of full output power, which is what a full day is usually equal to, indicating 375Wh down there in sunnier climes. Or about 73 Amphours at 13.6V here for the four midday hours, and neglecting anything outside of them,"
Does that read clearer?
I read this as you saying that you would assume 250 watt hours where you are for the four midday hours combined...or about 75 watts on a perfect day vs. your measured 63 watts right?
Then you extrapolate this to 375 watt hours for the same 4 hours down south or about 90+ watts per hour. Correct so far???
If you take the 375 watt hours and divide it by 13.6V...
that is 27 amp hours for the 4 hour peak period down south and less if you use the traditional bulk charging voltage of 14.4.
How do you come up with 73 amp hours ? I think that is a math error.
If I am correct then 8 hours of peak performance down south would result in 54 amp hours (2 x 27) and 12 hours would result in 81 but as you point out with your candlepower morning readings...there is really no possibility of getting 12 hours of full output.
Do you agree with these numbers and that 80 amphours or more out of the panels per day is a dream?
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You thought Brian had not claimed excessive output from the panels themselves and thought it was someone else...but here is his direct quote:
We bought 14 different brands of solar panels to determine which one was the most powerful, and after two years of testing, the BP350U was chosen. We were consistently able to exceed the STC rating of the panel in good conditions.
So he is saying that his panels will consistently exceed their 100 watt rating despite your measured 63 watts. Note that his ability to CLAIM output of OVER 100 watts is essential to his claim of 80-100 A/H's per day.
Just wanted to set the record straight that it IS Brian making these claims.
Here is the link to his full exposition:
http://archives.sailboatowners.com/p...07096173139.65
Based on your review of how the ACTUAL performance of the unit can easily be misinterperted by the product owner given what they see...and Brian's own statement that he is not scientist...I am
not accusing him of lying about the panels. Indeed...the fact that he gave them to you to test indicates that he believes in them. I think he is merely mis-informed about their real output just like the people that have bought them.
I would hope that he either refutes your tested findings in a scientific manner or stops making claims that you have refuted with testing.
You are obviously impressed with the quality and performance of the product he has put together and it should be able to find its niche with cruisers without needing to resort to marketing hype.
I hope you can get a measurement of wattage in direct sun on a perfect day before you turn 'em back in so we can really end this debate...but you deserve major kudos for the work you have done on behalf of your fellow sailors!
Let me know if there is anything you disagree with in what I have said as I don't want to spin your results.