July 17 Solar flare event

[Quattrohead]

I just happened to be in HA changing some settings when I noticed my panels were producing more than they are rated for, I thought I had buggered up a setting.
But no, checking on SA I am seeing the same large peaks. Some could be cloud edging but there was indeed a solar flare event during this time frame.
My Panasonic panels loved it !!!!

 

[sunshine_eggo]

Can you pull voltage and current for the same period?

 

[BillG]

interesting. I had a renogy charge controller shut down around that time due to over voltage condition. I have 3 30 volt panels in series which should never have exceeded the Renogy's 100 volt input cuttoff but they did... I wondered if there was some burst of energy from the sun that could cause that!

 

[Quattrohead]

Can you pull voltage and current for the same period?

No sorry, data is no longer available from HA...dunno why.

 

[sunshine_eggo]

interesting. I had a renogy charge controller shut down around that time due to over voltage condition. I have 3 30 volt panels in series which should never have exceeded the Renogy's 100 volt input cuttoff but they did... I wondered if there was some burst of energy from the sun that could cause that!

PV array temperature correction table (NEC 2017)

There are calculators like this one made by @upnorthandpersonal which help you calculate PV array voltage and power for low temperatures based on the specific specifications of your panels. These are great tools and will give more precise...

diysolarforum.com

Per above, you only have a 10% margin. That means if your panels are ever below freezing, you're likely to exceed 100V.

EDIT: It's worth noting that the OP's curves are for POWER not voltage. A doubling of the irradiance would nearly double the current and increase the voltage maybe 10%. In other words, what you're seeing in the above is due primarily to a boost in current with a small boost to voltage.

No sorry, data is no longer available from HA...dunno why.

Thanks for trying.

 

[n2aws]

interesting. I had a renogy charge controller shut down around that time due to over voltage condition. I have 3 30 volt panels in series which should never have exceeded the Renogy's 100 volt input cuttoff but they did... I wondered if there was some burst of energy from the sun that could cause that!

If they are 3 30 volt panels in series, and the renogy is 100v, you're dangerously close to overvolting due to temperature compensation.

As an example, for me (also in florida) .. I have to factor in a 14% buffer for voltage. it gets down to 22F in my areas lowest lows.. so with my 600v charge controller, I have to allow an 84v buffer for peaks. which means I can't put more than 516v in the series.

This info can be found in Table 690.7(A) "Voltage Correction Factors for Crystalline and Multicrystalline Silicon Modules" of the NEC.


Assuming you're actually using 30v (exactly) panels, this table means that in your location, the lowest expected ambient temperature cannot get below 32F. (32F is the lowest temperature that gives exactly a 10% buffer)

To be clear, I'm not saying you ran into temperature correction overvoltage in July.. but, you DO run the risk of damaging your SCC in the winter months.