Definitely agree. Mine produce over specification sustained. Not momentary. This happens only in the peak of summer, obviously at peak sun time.
They provide terminals for the connection of two sets of wires, per MPPT.
I checked your math. You may be missing the simple fact that there are panels around 48 volts which can be paralleled. In fact since the Sol-Ark has two inputs per MPPT, it is designed for such a setup.
Not missing it. I deliberately looked for the optimum size panel that would fit squarely inside both voltage and amperage range for maximum overall efficiency both in terms of panels to be mounted and feeds to the inverter. Any even multiples that add up to 810 watts would work. It could be done with parallel strings of 200 watt panels presuming they are available in 48 volt output. Look at it as 810 watt panels would require 24 panels in 3 strings of 8. 405 watt panels would double to 6 strings of 8 which fit the wattage/voltage/amperage requirements but incur a lot more mounting hardware cost.
what current would you pick to 'pair up' with Voc? Ioc = 0
Seriously Voc is 'picked' to account for worst possible condition in 'voltage' sense plus it needs to be pro-rated up to account for coldest temp at the location. Impp is 'picked' to ensure it is within acceptable range during actual operation.It's not about pairing up. No professional company would exceed any of the 3 ratings when it comes to PV: total Voc, total Isc, or total KW. You can argue with them until you're blue in the face. I'm just telling you that that's what they're going to stick to.what current would you pick to 'pair up' with Voc? Ioc = 0
are you saying Isc is checked against Imppt of inverter, what for? Isc is only used to specify PV wires amperage (in case of short they have to sustain it), it's nothing to do with 'exceeding' inverter's input.
I don't think there is even an argument among forum members on this point.
do you mean the inverter specs are overly 'optimistic' and installer would be left holding the bag? That's a possibility and makes their position understandable, I was mostly interested to see if I'm missing something.
I think the specs are under-rated if anything, but the installer does what the installer does is my point. Imagine if you get someone to roof your house, but then you tell them to do it differently, or use different products that they normally do. The installer will likely get cold feet, or refuse to change because they know how what they use performs. They know where to buy it, what to expect performance wise, how to get it to seal up.
Yes, that is what I'm saying. I myself over-panel my inverter, so I never disagreed with OP in the first place. But that's DIY, I've yet found/seen any company that does that.
it must be that 62° angle and low temp of course. Here in sunny CA I've only seen 80% max from the panels (LG mono feeding to SMA inverters well within their specs), but the panels are at 17°, just laying parallel to the roof. PV Watts gave pretty close estimate for location/azimuth/inclination so I'm not even trying to improve that.
That's true, if they pretend to be solar experts. It might be - barely - fine if they were just electricians for doing the AC out side.
Batteries and loads don't push or pull either, that's not special to panels. The V * I considerations for MPPT tracking are not battery or loads related but a different subject.
I got hung up here. 4/12 is basically flat.
Keep in mind that they will produce a substantially higher output when cold. So measuring them right now isn't going to show you that. IIRC there was someone on here back in January complaining about blown MPPTs because their panels had over-performed in the cold weather.
That is why I only have 8 in series to an MPPT. Each panel is rated 48.1V for Voc or about 385 volts total for the string. I can safely add one more panel if needed. I've been told these panels can produce close to 900 watts at -20F. Fortunately, the lowest we get is usually about 0F.
