System help/info

[jscusmcvet]

we invested in a system from Signature Solar last year. It took about 7 months for me to complete the install and switch over. (I work full time plus). We are in NC. We have a 2300 sq. ft home.
Our system is:
2x EG4 6500 Inverters
6x EG4 5000KW batteries in a tower
30x 400 watt panels, south facing, 25 degree mount, arranged in 2 strings, one 14 panels, one 16 panels.

• Our goal is to off grid completely if at all possible.
• We are successful in that goal as long as we have sun.
• Without sun we last about 1.5 days.
• We heat with wood
• Our clothes dryer is in the barn, on grid, separate from the house.
• We cook with wood.
• We have done a lot of adjusting with all LED's, etc...

Is this what we can expect from a system this size? If I need to expand the system, where to start?

Sorry for the newb questions. I feel experienced since I did the install on my own, I just don't know how to complete the evaluation to decide what to do.

Thanks for sharing your expertise.
John

 

[WindWizard]

Without a generator, then it will be difficult no matter what you do. When the sun plays possum for days on end and the snow comes down for a few days, then it kills all your solar no matter what you have. I have batteries for 3 days and 42 panels and the months of Nov-Jan still find me needing more juice. It comes down to when is enough enough. There will always be that period where the sun just does not cooperate.

I heat with wood and have a wood cookstove for backup but if I was to detach from the grid then I would be running a generator which is more expensive than the grid.

 

[jscusmcvet]

Without a generator, then it will be difficult no matter what you do. When the sun plays possum for days on end and the snow comes down for a few days, then it kills all your solar no matter what you have. I have batteries for 3 days and 42 panels and the months of Nov-Jan still find me needing more juice. It comes down to when is enough enough. There will always be that period where the sun just does not cooperate.

I heat with wood and have a wood cookstove for backup but if I was to detach from the grid then I would be running a generator which is more expensive than the grid.

Thank you for your reply. I suppose we are in the throes of "How much do we want true off grid?"

 

[42OhmsPA]

Are you able to adjust the tilt angle?
I recently finished a ground mount and angled it for winter, it blows the shallow angle roof arrays out of the water even though they have 500w more of panels.

Have you measured your inverter idle current? You're likely burning a decent chunk of your capacity there. This time of year stinks for solar with the low sun angle, short days, clouds, fog, snow, etc

 

[740GLE]

You can never have enough storage.

Prove me wrong.

 

[green mountain boys]

If you are like everyone else, you are having the most trouble on the shortest days of the year, right? When the sun is at the lowest angle?
Your array is mounted at 25 degrees from horizontal?
Is your array facing south at 180 degrees?
Try plugging what you have into this calculator and record the results. Then change just the angle of the panels to 55 degrees from horizontal and compare the results. I think you will be surprised.

https://pvwatts.nrel.gov/

Try changing other variables and see what will work best for you.

 

[jscusmcvet]

If you are like everyone else, you are having the most trouble on the shortest days of the year, right? When the sun is at the lowest angle?
Your array is mounted at 25 degrees from horizontal?
Is your array facing south at 180 degrees?
Try plugging what you have into this calculator and record the results. Then change just the angle of the panels to 55 degrees from horizontal and compare the results. I think you will be surprised.

https://pvwatts.nrel.gov/

Try changing other variables and see what will work best for you.

I tried the calculator and it seems we are about idea at 25 degrees. At 55 degrees, we lose 20%. Thank you for the calculator though. Fascinating to piddle with.

 

[jscusmcvet]

Are you able to adjust the tilt angle?
I recently finished a ground mount and angled it for winter, it blows the shallow angle roof arrays out of the water even though they have 500w more of panels.

Have you measured your inverter idle current? You're likely burning a decent chunk of your capacity there. This time of year stinks for solar with the low sun angle, short days, clouds, fog, snow, etc

Can you explain "idle current" and how we measure it? Thanks

 

[42OhmsPA]

Can you explain "idle current" and how we measure it? Thanks

Idle current is the power an inverter/AIO uses to simply be powered on with zero loads in "idle".
You would measure it with a clamp meter / ammeter or a shunt.

 

[740GLE]

If you power off all AC in the overnight you’d save a bit of Whr, a fridge can handle 8-12hrs of loss of power without AC assuming you’re not raiding it for a mid night snack.

 

[green mountain boys]

I tried the calculator and it seems we are about idea at 25 degrees. At 55 degrees, we lose 20%. Thank you for the calculator though. Fascinating to piddle with.

If your not generating enough power in the short winter days, you can tilt the panels to a steeper winter angle like 55 degrees. This will reduce the annual production total but increase the winter production when you are shortest on power. The calculator shows the results in the monthly production total. It depends on your needs. If someone is off grid then they might want to sacrifice some total annual power production for increased winter production.

 

[jscusmcvet]

Thanks all. We are in the process of reviewing our uneeded usage... vampires.... I really appreciate your help. I would say we operate about 90% of the time off grid. It is just the multiple cloudy days. Thanks again - John