mppt vs pwm

So what the graph says is the closer the input voltage is to the output the better. Wait, that's what I said pages ago. lol

Where on the graph would CA's 91v be or even something in the mid 40's going down to 12v?

Salvo wrote:
There are a few that run that high voltage.

My point is that your were cherry picking with your proclaimed 0.2% difference in efficiency. As Wiz says, solar almost never outputs max watts. Low irradiation in the mornings and battery surface charge are the main factors that prevent max current when the batteries are at their lowest SOC.

12thgenusa wrote:

How many folks are running an 85-v input?

Not cherry picking at all. This has nothing to do with mornings, low irradiation, battery surface charge or what panels one has. This is about controller efficiency at various voltages.

My point is that if one wants to point to wiring panels in series as a reason for poor performance he had better look elsewhere.

Here is the graph for all to see and make their own conclusions.

When you get around to it, I know I would appreciate seeing the results.

Jim,

I may indeed do some testing even series vs parallel with 2 panels. Easy to do since I have MC4 connectors on each solar panel wire. But it will be awhile...

The MPPT controller with MSView will also log input and output I, V, P although I don't know how accurate the values are. Likely I will just report what it says. Even Solar Guppy will log various values.

CA Traveler wrote:
My three panels are about Vmp = 91V. The plan was more wattage than needed for efficiency and flat mount. Doubt I'll ever rewire for parallel. However should I upgrade for 4 panels it would require series/parallel.

Of course I planned correctly and will never want a fourth panel!
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maybe

You could always just put ONE panel into the controller and see how the output at lower voltage x 3 compares with all three in series.

Hi Salvo,

Few of us have your understanding, or even the ability to understand. Please do tell me why 4 amps vs 5 amps is not 20% more? Granted it is not nearly "real world" and misses a host of other complications.

I know that today, given the low price per watt of solar, that I'd likely do pwm, since they controllers for that also do temperature compensation.

Salvo wrote:
Jeez Don, I would have hoped you knew more about solar and would know that video is bogus. I'll leave it up to you to figure out why.

Right, Don needs to review that thread.

I think Rogue dropped his gains after the discussion from 20% down to 8%; but it's been a while.

My three panels are about Vmp = 91V. The plan was more wattage than needed for efficiency and flat mount. Doubt I'll ever rewire for parallel. However should I upgrade for 4 panels it would require series/parallel.

Of course I planned correctly and will never want a fourth panel!
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maybe

Some time back a thread took Rogue to task for their mppt claims which were much higher than pwm. They backed down.

Don

Thank you for posting the video. It was pretty basic but the discussion has been very enlightening.