Panel production accuracy?

[Mannfamilywoodworks]

Hello fellow solar enthusiasts, I’ve got a head scratcher on this fine sunny New York day.

I’m noticing that I’m using my generator to top
My battery off daily and I’d like to fix that.
I charge the battery to %99 SOC at night with the generator and by the morning it’ll be at around %70 SOC …throughout the day it’ll drop about %30 or sometimes it’ll stay at where it was…

I have 6 -235watt panels in good conditions I’m expecting…1410watts?
Is my math correct?
I don’t think I’ve ever seen those numbers on the inverter though…

They’re hooked up 3s-2p

Growatt 6k AIO Inverter states
I’m getting 245watts in direct sunlight right now and it’s got me very confused.
It’s slightly cloudy now that I’m staring directly at the sun lol

Any ideas as to why I’d be experiencing such poor power production from these panels?

 

[Mannfamilywoodworks]

Now it’s reading almost 500watts
9amps
88v

Would this mean that 2 panels are producing out of 6?
I feel as if I’m missing something here

 

[Any name you wish]

In your first photo, you see the line above the box that talks about STC? That is how your panel will produce in perfect lab conditions. You need to find the spec sheet on those panels and find their PTC rating. This is going to be the closer to real world output.

 

[Mattb4]

With your Northern location, the Winter season and solar panels that are mounted flat, you will not get the best output. Now the question becomes are you getting as much as you should allowing for all of that? About the only way you could find out is to test individual strings and panels for output and see if you get discrepancies. A short while back I had my array lose 1/4 of production due to a loose MC4 fuse holder. So things can happen.

 

[Mannfamilywoodworks]

In your first photo, you see the line above the box that talks about STC? That is how your panel will produce in perfect lab conditions. You need to find the spec sheet on those panels and find their PTC rating. This is going to be the closer to real world output.

Ahhh I see. Makes sense. We’ll we’re on the right track.

 

[Mannfamilywoodworks]

With your Northern location, the Winter season and solar panels that are mounted flat, you will not get the best output. Now the question becomes are you getting as much as you should allowing for all of that? About the only way you could find out is to test individual strings and panels for output and see if you get discrepancies. A short while back I had my array lose 1/4 of production due to a loose MC4 fuse holder. So things can happen.

I was wondering if angling them would help? Do you think it would?

 

[schmism]

I was wondering if angling them would help? Do you think it would?

you can use this website to get an understanding of how much sun you get changes throughout the year for your location.

Solar Irradiance Calculator

www.solarelectricityhandbook.com

for instance, my location is currently getting about 60% of the sun you get in the summer. (in ideal conditions) so understanding that my pannel output is 60% of the sticker right now, is fine with me.

 

[Mattb4]

I was wondering if angling them would help? Do you think it would?

Yes it will help. You can look up your location at https://footprinthero.com/solar-panel-angle-by-zip-code

 

[Zwy]

Hello fellow solar enthusiasts, I’ve got a head scratcher on this fine sunny New York day.

I’m noticing that I’m using my generator to top
My battery off daily and I’d like to fix that.
I charge the battery to %99 SOC at night with the generator and by the morning it’ll be at around %70 SOC …throughout the day it’ll drop about %30 or sometimes it’ll stay at where it was…

I have 6 -235watt panels in good conditions I’m expecting…1410watts?
Is my math correct?
I don’t think I’ve ever seen those numbers on the inverter though…

They’re hooked up 3s-2p

Growatt 6k AIO Inverter states
I’m getting 245watts in direct sunlight right now and it’s got me very confused.
It’s slightly cloudy now that I’m staring directly at the sun lol

Any ideas as to why I’d be experiencing such poor power production from these panels?

Flat mounted on a shipping container will influence yield. Input your location/data into this calculator and it will calculate tilt angle and production based upon sun position thru the year. https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP

I prefer seasonal adjustable mounting due to reduced yield around winter solstice. Use the off grid tab and compute what is needed to keep batteries charged. I use 60 to 65 degree slope for winter and 30 degree slope for my location around solstices as my mount is adjustable. At 45 degrees fixed, I would not be able to keep my battery charged the 30% of days in December for example.

For the GW inverter, float voltage is usually set about 0.5V below bulk.