Sounds to me like someone is misrepresenting their products. A solar panel's VoC should be its maximum possible output in ideal conditions (open circuit). If that's under your product's maximum input voltage, it should be no problem. Ever.
Is EcoFlow advertising a higher input voltage than their products can actually take, assuming most people won't actually reach it due to temperature inefficiencies? That'd be false marketing, and it'd make this article manipulative, false blaming of the customer.
All solar panel datasheet have temp coefficient, eg for one random ecoflow solar panel:
source https://websiteoss.ecoflow.com/cms/upload/2022/10/15/-139121...STC ("standard testing conditions" for solar panels) is 25C so if it's freezing 0C you have 25 multiplied by 0.33 Volt = 8.25 Volt more than STC in open circuit situation.
Unfortunately inverter manufacturers seldom document how many Volt will destroy the MPPT and up to how many Volt the MPPT will safely turn off by itself before breaking.
Not to mention a fail-safe MPPT would/should just crowbar the input if there's any potential for overvoltage.
Solar panels are current sources that waste their power into a long string of silicon PIN diodes that eventually reach their forward voltage and begin to eat up all that juicy current. You can just take the current and keep the voltage as low as you want, just make sure to take all the current or it's voltage will rise to let the diodes take the current you aren't using.
> A solar panel's VoC should be its maximum possible output in ideal conditions (open circuit)
I think this is where the confusion arises - what do you mean by ideal conditions? Ideal conditions for solar generation are not necessarily at the same time as the highest voltage operating conditions. VoC tends to be specified at Standard Test Conditions which has light-levels representative of a sunny day (1000 W/m2) and a cell temperature (not ambient) of 25 degrees C, which is already a lot cooler than most panels would typically be at that level of irradiance. So really, the label is already specifying a voltage higher than what you would typically experience during times of max generation.
However, the max voltage could exceed this rating at times when there are cold ambient temperatures with enough light for the module to function, but not enough sun to meaningfully heat the cells. So in this scenario you may have maximum voltage, but you're far from maximum power nor at 'ideal conditions'.
What does “maximum possible voltage” mean for a solar panel? Do you include things like cloud edge effect (which increases incident light beyond direct sunlight?) What about installs with a nearby window reflecting light onto the panel? Do you include ultra-cold environments (which will reduce the resistance and therefore often increase voltage, although admittedly not, I think, Voc)?
VoC is the maximum potential voltage a cell is physically capable of producing. It does not consider real-world conditions. Rather, real-world conditions cause the solar panel's output voltage to be somewhere between 0 and its VoC.
Voc is just the open circuit voltage measured at the terminals (plugs). “Nameplate” Voc is at standard test conditions (STC) of 1000 W/m^2, 25 deg C cell temperature, and a standard are mass/spectrum. The combo of 1000 W/m^2 and 25 C cell temp is not common in the real world in most climates, but still happens. Even relatively hot climates can have times in winter that exceed nameplate Voc if inverters turn off (making the panels go to open circuit).
Obviously you include everything, otherwise it wouldn't be a maximum. You can define a minimum temperature for this, of course, but the customer should know about it.
There's no theoretical maximum voltages for solar panels like there kind of is for batteries. They're just giant array of photodiodes and they just generate whatever voltage potentials proportionate to amount of lights received.
You could produce a "max voltage flying low earth orbit over Gobi with no shadows from Starlinks" value, but that's just the value for circumstantial most absurd situation you happened to have come up with, not a guaranteed theoretical maximum.
The current is what varies proportionally with the amount of light received.
The open-circuit voltage depends mostly on the structure of the solar cells and on the temperature. It has only a very weak (logarithmic) dependence on the amount of light received.
The voltage that you measure at the output depends on the open-circuit voltage, on the amount of light received and on the amount of current that you draw from the panel.
The maximum open circuit voltage for a solar cell is easy to estimate, because it happens at the minimum temperature for which it is designed and the maximum solar illumination. It can be exceeded only using a light concentrator that projects on the panel light collected from a much greater area.
So it is doubly important that all equipment downstream has overvoltage protection?
In fact considering there is no theoretical maximum, it would be downright negligent not to have overvoltage protection
Yeah, billowing magic smoke just sounds wrong. No disagreement there.
There is a theoretical maximum: the open circuit voltage of a single photovoltaic junction cannot exceed the bandgap of the semiconductor used, no matter how much light you apply. The manufacturer knows the semiconductor used and the number of junctions in series.
They produce current until the diodes start conducting given the forward voltage, as they'll take any current you don't extract off of your hands.
Of course if you want to extract maximum power you have to balance the higher worth of the current you take against the loss of current to the diode forward conduction.