My present array does make the full power without MPPT during "high noon". And on really cold days I've gotten upwards of 1,300 watts from it. The Sharp 123's are "standard" panels that go to something like 20 or 21 open volts - they are 12 volt. I have ten of them wired series parallel for 24 volt.
Sorry to argue, but you are NOT getting "full power".
A panel that'll make 20-21V open circuit will have a peak power at about 17.4V, depending on temperature etc. (*2 for a "24V system")
If your batteries are at float voltage, you won't be soaking up full power, so lets not even consider that.
So lets say your batteries are "nearly" charged (so they have a reasonably high terminal voltage, but still taking charge). Lets say 28V.
That's just about 7V of mismatch. I'm guessing your panels "peak output current" is about 7A. So 35A for your 5 parallel strings.
35A * 7V *WASTED* = 245W. Almost 20%!.
These new panels are called 20 volt panels by some people - others call them 29 volt panels. Their open voltage only goes to someplace in the low 30's and their optimum operating voltage is about 29. According to Adam's description, they should perform quite well on a 24 volt system without MPPT because they have a closer match between the optimum operating voltage vs load.
Much closer, sure.
What I am concerned about is getting too much peak power during "high noon". My panels run wide open all the time. In other words I do not have any sort of voltage controller, PWM, charge controller, etc., hooked to them. Instead, when my bank gets up to full charge my Morningstar RD-1 turns on water heater elements in two 2 kW stages. The water heater elements are standard 2,000 watt 240 volt elements powered by the inverters and the inverter load on the battery bank controls voltage when the bank is full.
ok, so just a big dumpload.
On a good day when I'm getting 1,300 watts from one array, 1,000 watts from the new panels, and 3 kW from turbines, I will have too much power. 4 kW of water heating load is not going to keep up, and I don't need more water heating power.
The reason I'm adding these new panels is to provide more power in the winter when the days are short to reduce run time on our Generac EcoGen for water heating. But I think they'll need to be "throttled" somewhat because of the above scenario where I'll get too much peak power during "high noon". I would like that to be reduced and get a longer period of lower average amps.
Makes sense.
What I was wondering is if, instead of facing the panels due south, if I would place half of them facing SSE and the other half SSW if this would produce the same kWh in a day as having them all face due south, but reduce the peak amps during "high noon"?
If you deliberately aim your panels where the sun is well before solar noon, and well after, you will get largely what you're after.
You will want to be reasonably well "off axis" though. A 30 degree off-axis error will reduce output by about 15%
Where I am, today, the sun will be 47 deg above horizon and due north at solar noon.
At 10am, it'd be 8 degrees lower and 39 degrees further east.
If you pointed your "morning" panel there, it'd get peak power at 10am and be 30 degrees off-angle at solar noon, down 14%.
Similarly, if you had "afternoon" array pointing where the sun would be at 2pm, it'd be 8 degrees down and 39 degrees further west,
the same 30 degrees off-axis and down 14% at noon but giving full output at 2pm.
The morning array would be 60 degrees off-axis and down 51% when the afternoon array was producing full output,
as would the afternoon array be 51% down when the morning array produced peak output.
Is 15% down from each "enough" at noon? You might have to move them to point further east and west respectively - some modeling would make short work of it.
(easiest way is just do vector dot.product of the normalised vectors of each angle - sun and each array)
