classic string sizer tool

[Bryan]

I have a question regarding using the classic string sizer tool.  I can see that one is supposed to enter the "stc" rating for panel power input box.  Since one usually wouldn't expect STC power from ordinary solar panels in most installations (more likely NOTC or even less), what is the reason for this?  Will a classic possibly burn out if two much panel power happens to be available at it's input  for a given solar condition?  Or, does these units have the capability to limit the output power with internal protection?  I know oversizing like this may waste power at times, but my location sees lots of overcast conditions where I would like to have the "extra" overhead available.

[Cniemand]

STC most of the time will never happen, however, you can get special weather effects that will magnify the suns intensity, cloud edge effect for example, where you see you 2000 watt array suddenly producing 2200 watts. I've actually seen mine do over the stated quite a few times over the past 3 years. One time it was 2400 watts! Crazy.

Mainly you have to be aware of it because in cold temps the voltages do shoot up quite a bit. The Classic has a great design to be able to Hyper VOC so you can safely have a larger array that rarely sees those conditions but as it states, you would not want to rely on oversizing it that way because it would be wasting useful energy having the system shutdown until the voltages drop to be safe to pass through.

One of the reasons I chose the Classic was because it came in a 200v version. I could connect 4 panels in series for 150v in. With our possibility of -40C/F outside that would bring it up to 180-190v incoming. Leaving it to be a fully functional system without frying anything internal.

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