On Mon, 10 Dec 2018 09:53:05 -0500, "Jim Wilkins"
>> ...
>> The better test will be how it performs with a more deeply
>> discharged battery bank and all of my panels. That will have to wait
>> for a forecast of a clear sky.
>>
>> -jsw
>
>Clear sky, discharged battery. The sun is low at 9AM in December at 42
>North, so I don't expect the 100% rated power I measured earlier.
>
>The 2s2p array of 100W panels gave 9.7A from a PWM controller, 11.6A
>from this MPPT. That's ~20%, close to the value of adding one panel
>instead, though I'd need two for this 24V bank. It looks like I'm at
>the break-even point where the cost of larger wire and space for
>panels drive the decision whether to buy MPPT or more panels.
>
>-jsw
>
I'm near an area where there is a good bit of solar turnover (someone
buys a house with solar installed and doesn't want it - maybe the wife
thinks the panels are "ugly" - or someone discovers a year or two in
that the high end of the promised solar power doesn't happen all
year). The year or two old removed panels (typically 250W 960 cell]
or 300W [72 cell]) go for $.40 - $.60/watt (no shipping because I'm
close enough to drive my truck). Some of these are excellent panels -
I have a couple of 250W Jinko that actually deliver 235W in full sun
(that's 94% of rated wattage after any losses in the wiring or the
MPPT controller). I paid around $25-$50 each for those panels but
the measured output makes them a very good buy when new 100W panels
are in the $00-$40 range on Ebay.
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>> The better test will be how it performs with a more deeply
>> discharged battery bank and all of my panels. That will have to wait
>> for a forecast of a clear sky.
>>
>> -jsw
>
>Clear sky, discharged battery. The sun is low at 9AM in December at 42
>North, so I don't expect the 100% rated power I measured earlier.
>
>The 2s2p array of 100W panels gave 9.7A from a PWM controller, 11.6A
>from this MPPT. That's ~20%, close to the value of adding one panel
>instead, though I'd need two for this 24V bank. It looks like I'm at
>the break-even point where the cost of larger wire and space for
>panels drive the decision whether to buy MPPT or more panels.
>
>-jsw
>