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John, I'm not sure I'd be that hard on it. To a large extent, yes, the performance comes from the components (PWM), but there's also a significant boost from being able to rotate/angle the panels--which it allows very simply and robustly. If someone else designed some kind of "ball mount" to allow solar panels to be stuck on a pulpit and rotated that way...But I don't know that there is anything like that on the market, capable of holding panels up in +20 knots, much less what the SS can hold them in. (I figure, by 20 knots the wx is closing in and I'd want to stow them anyway.)
The numbers indicating the affect of angling the panels, seem to come from "no load" conditions, and that's simply not right. I haven't seen numbers under load yet, I'll try to get some.
Sailingdog-
Jeez, you guys are gonna extort all the dribs and drabs from me before I can get it all finished in one piece. I checked/changed the panel angle before each set of measurements, every 1/2 hour at the outside.
9:15 AM, batteries measured under no load as 12.30 volts and 12.24 volts, the latter being B2 and connected via the A/B switch and the boat's cabling--not directly.
10:15 AM, "bulk" charge indicated, remote showing 13.2V to on the batteries as I started the tests--and it took me a while to figure out the SolarBoost setups after this point. The SBoost was connected directly to B1 only, flowing into B2 via the A/B switch set to "both" during the whole day.
Next note has no time mark, shows 13.10 (my meter) at the batteries with the SBoost showing 13.4 out to them, my meter showing 15.70 V out of the panels. I'm not sure if there's an error in the note regarding the 13.10/vs/13.4 difference here I think I was still fuzzy brained from trying to understand the SBoost programming.
11:00AM, 15.42 in, 13.37 out, measured by my meter on the SBoost terminals. The sun was already full brightness (per the Gossen meter) and the SBoost was still in "bulk" mode using the default wet lead facotry settings.
At that point I checked the SBoost reaedings, 13.3V @4.4 Amps shown, versus my multimeter 13.14V@4.27A shown (using separate shunts, one in the positive lead, one in the negative) so I was indicating 56.1W and it was indicating 58.5W, either a 95% or 104% difference depending on which side you look at. To me that just means either the SBoost display metering was off by 5%, or the effect of PWM on my DC meter was 5%. I don't know.
By 11:15 AM it was showing 13.6 volts @ 4.^, for 62.56W charging.
At 11:20 I measured 15.81V into the SBoost and 13.36V out of it, against 13.5-13.6 showing on it's panel. In theory the SBoost was providing about a 6-7% net gain, putting out 4.7A @ 13.6V instead of the 4.4A at 15.81V that was coming out of the panels. (Check my math, but that's what I wrote at the time.) I went on to about 1AM but didn't see any significant increases in any numbers, which didn't surprise me since 11AM-1PM would all be "peak" output time. I was surprised not to see anything near 100W coming out of the panel array though, it was only around 85F so I can't blame that on heat.
CD-
I don't know, I'm hard put to stick a number on the gain. I mean, which numbers do we go by? The 5% difference in meters, indicating....which one is right? The 10-20% difference in battery gain/performance, that PWM is supposed to add? The 6-7% net gain in charging amperage that I did measure? If the 6-7% is real, and the 5% metering difference is from my DC meter being "low" due to the PWM...that would mean an 11-12% gain from the MPPT controller alone. Plus the real but elusive "gain under load" from the angled panels, which might be that much again or more. And then, there's the battery gain from PWM...where or how do we write that one up?
All that I'm saying, is that to someone who doesn't split up those pieces, the change from flat panels to this system could appear to be a huge difference, I suspect possibly 30-40% overall depending a lot on how their batteries responded to the PWM charging.
Still, if the gain from angling the panels really is (let's say) 10%...and you add the gain from the MPPT as another 10%...
What did Alan Greenspan say? A couple of million here, a couple of million there, sooner or later you're talking real money.
This puts me in mind of some testing that Consumer Reports did on 35mm cameras a million years ago. They surveyed repair shops and asked what models they did the most repairs on, then compared that to sales figures. And they paned Nikon as needing too many repairs. What they forgot to factor in, was at that time essentially all the pros used Nikons--in the rain, on the beach, all day all night everywhere, so the cameras took a lot more abuse than the ones used twice a year at weddings and vacations.
I think I've made a start at turning up some of the real issues, but a lot more needs to be done to get the real answers.
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