Is endless oversizing an inverter giving any danger

[Solarudi]

PV oversizing to inverter power

Hello, I think the question of oversizing is due to the old times with high priced solarpanel and te wish not to waste energy. A chief engineer from Ginlong and other said, doesn´t matter as long the VOC is not exceeded. The inverter takes the energy it can use, not used solar energy is making heat, but in rainy times it can avoid the use of batteries.

I have 9000W on a 5.5KW hybrid inverter..had, 5 "died", but only in battery mode at nighttime due to high voltage spikes made by the inverter. I search at time for an affordable improvement. My goal is to offer solar glass replacements for metal sheet roofs in the Philippines. Thanks

 

[Ampster]

High DC to AC ratios (oversizing panels to inverter) is mostly an economic decision that should be based on optimizing annual production cost effectively. When panel prices were high it was less attractive economically to have a high ratio. Today, I have heard that many solar farms run ratios as high as 1.6 to 1. i have not heard of any danger in oversizing panels to inverters as long as inverter voltage input is not exceeded.

 

[Hedges]

Voc limits must not be exceeded, including with temperature adjustment for record cold. How cold does it get in your customer's locations? Here where it freezes, voltage could rise 16%.

Many inverters are able to handle arbitrary over-paneling in terms of excess available current. Except, many have clamping diodes to protect against reverse polarity, and those would be damaged. If you connect one string first and confirm operation, that problem should be avoided. Some can't handle excess available current.

Overpaneling PV STC wattage about 1.5x is necessary just to deliver peak desired wattage, because panels rarely reach STC.
You can parallel PV strings of different orientations. If you put half the panels on a roof sloped 45 degrees facing west, and half facing east, you could overpanel another 1.5x without exceeding max wattage. So I'd be inclined to overpanel at least 2.25x. Because production is reduced off-season or during overcast, I might want even more.

 

[zanydroid]

There is a pretty extensive thread and guide on this fwiw.

I will add here that if the MPPT gives a hard Isc or other current limit, don’t exceed that. And the absence of say max fuse rating or Isc does not mean there is no limit. You may want to consider adding fusing at a multiple (say 1.56) of the expected operating current, but this is more for safety and not for protecting the hardware in all cases

A Tier1 MPPT probably has enough necessary protections to at least not catch fire.

Standard solar panels as roofing material is another problem… maybe someone has figured out a way to make that serviceable but there are many challenges. In the developed countries you could say a large % of the R&D in solar shingles went towards making it look good, but i would guess it’s at most 50%. Vs reliability serviceability and efficiency. There are cooling and physical form factor issues.