Total VOC

[clayswen]

I have been reading this forum for a few months and have gained some valuable knowledge. I joined so I could ask some questions. I understand the VOC of a panel array and I also understand the maximum voltage on the inverter, but the one thing I haven't come across is the difference in systems and VOC. My question is when you have a grid tied solar array, when are your solar panels in VOC? With an offgrid system I can wrap my head around it more because the system would be sitting idle at periods of time with no load. Someone enlighten me.

 

[timselectric]

I have been reading this forum for a few months and have gained some valuable knowledge. I joined so I could ask some questions. I understand the VOC of a panel array and I also understand the maximum voltage on the inverter, but the one thing I haven't come across is the difference in systems and VOC. My question is when you have a grid tied solar array, when are your solar panels in VOC? With an offgrid system I can wrap my head around it more because the system would be sitting idle at periods of time with no load. Someone enlighten me.

In the morning and evening when not enough light to produce amperage.
And each time the MPPT does a sweep.

 

[timselectric]

And the most dangerous time is when the grid goes down.
During the fraction of time it takes to respond to the loss of grid.

 

[clayswen]

Okay that makes sense. I am getting my system together piece by piece and I am just making sure I do everything correct. I purchased a Sol-ark 12k the other day, but have yet to purchase my solar array. I chose a hybrid so I could power my panel in the event of the grid going down during daylight, but also wanted to add a battery later.

The panels that were recommended to me were Canadian 390w (36.4 VOC) with an array of 26 panels with 13 in each series. The more I looked at it I could only safely do 11 in each series. Max operating watts for the inverter is 9000, so I would only be at 8580 watts total which is a little lower than I would like.

Am I on the right path with this thinking?

Sorry forgot to add the sol-ark has a 500v max on each mppt input.

 

[timselectric]

Okay that makes sense. I am getting my system together piece by piece and I am just making sure I do everything correct. I purchased a Sol-ark 12k the other day, but have yet to purchase my solar array. I chose a hybrid so I could power my panel in the event of the grid going down during daylight, but also wanted to add a battery later.

The panels that were recommended to me were Canadian 390w (36.4 VOC) with an array of 26 panels with 13 in each series. The more I looked at it I could only safely do 11 in each series. Max operating watts for the inverter is 9000, so I would only be at 8580 watts total which is a little lower than I would like.

Am I on the right path with this thinking?

Sorry forgot to add the sol-ark has a 500v max on each mppt input.

The most important number is VOC.
Never exceed this, or damage can occur.
Don't forget to calculate for the lowest record temperature in your area. Voltage increases at lower temperatures.
Going over on amperage (or wattage) is ok. It helps get more production in the morning, evening, and on cloudy days. But Going over too much becomes wasteful.
Just remember that Voltage is pushed, but amperage must be drawn.