Solar System Install and Performance

[turbo392]

I can't find wording that would confirm or deny this, but that would be my assumption as well.

I think the theory behind it is in a grid tied setup if the energy isn't used within the home it is put back to the grid and still utilized by another consumer.

They want a smart meter in your home to disable your a/c during a heat wave to keep the cooling going in the government offices.

 

[JayT]

My next property I plan on doing a full off grid system. When the power goes out, and it will, I won't even notice. I probably don't want government grants because they're just going to tell me what I can and cannot do.

 

[team dirt]

My next property I plan on doing a full off grid system. When the power goes out, and it will, I won't even notice. I probably don't want government grants because they're just going to tell me what I can and cannot do.

My cabin is totally off grid and I have built 3 massive off grid systems for friends. Make sure you have a good generator and a good sized diesel tank. From November to April you will run about 3 hours per day of generator time. Summer you can usually get away with no geny time if you are smart with how you use power unless it clouds over for a few days. Batteries will last 10 years at best and are anywhere from 4000 to 12000 depending on what you go with and how much capacity. If you have an option for grid tie I would stay hooked up.

 

[JayT]

My cabin is totally off grid and I have built 3 massive off grid systems for friends. Make sure you have a good generator and a good sized diesel tank. From November to April you will run about 3 hours per day of generator time. Summer you can usually get away with no geny time if you are smart with how you use power unless it clouds over for a few days. Batteries will last 10 years at best and are anywhere from 4000 to 12000 depending on what you go with and how much capacity. If you have an option for grid tie I would stay hooked up.

What size generator would you recommend for it? I plan on pole mounting the panels low enough so I can blow them off with a leaf blower in the winter, and adjust their angle that should help. I really don't want to grid-tie anything. We are trying to build a property that does not rely on the grid for anything, as much as possible anyways

 

[Dawizman]

What size generator would you recommend for it? I plan on pole mounting the panels low enough so I can blow them off with a leaf blower in the winter, and adjust their angle that should help. I really don't want to grid-tie anything. We are trying to build a property that does not rely on the grid for anything, as much as possible anyways

Best bet is to get a pole mount with adjustable elevation angle. Adjusting your panels to the correct angle in winter will not only optimize solar collection, but will minimize or eliminate snow buildup as well.

I have remote tower sites that are solar powered that never need attention. The array is mounted nearly vertical though which is not optimal for summer. In my case, the array is sized to run the load during winter months, so even at a 20% efficiency reduction in the summer, the batteries hardly drop below a full state of charge.

 

[team dirt]

What size generator would you recommend for it? I plan on pole mounting the panels low enough so I can blow them off with a leaf blower in the winter, and adjust their angle that should help. I really don't want to grid-tie anything. We are trying to build a property that does not rely on the grid for anything, as much as possible anyways

We usually run 10,000 kubota diesels. This way when the geny is on and charging at 100% you still have enough capacity to run anything in your house without the inverter kicking out the charger every time a load comes on like a water pump or the fridge pump kicking on. If you can run a propane fridge or natural gas if it’s available to you. That keeps a lot of load off he system. My water pump is one of my biggest draws so I installed 2 large capacity pressure tanks so when the pump does come on it runs a long time to stop the inrush draw. I get appx 30gallons of draw before the pump starts again. Also install a auto generator start module so you don’t need to always be paying attention. If you watch your consumption it’s very easy to be off grid but it is very costly compared to grid power if it’s easily available. We have been switching back to the lead acid batteries from the AGM now as they seem to last longer and you can equalize them and bring them back where the AGM there is nothing you can do. Lead acid is way cheaper per amp hour but the maintenance must be done on them. Also make sure your grounding is really good. If you have any kind of power issue it can fry a lot of your system.

 

[ABMax24]

Well another year gone (almost), and still nothing abnormal to report with our install. Everything is still functioning as it should, and our production this year was higher than the last 2 years.

We installed a central AC unit in June (a week before the big heat wave) and that has turned our 10% annual surplus into 5% deficit, but it was well worth it.

As power prices continually creep up I'm definitely not regretting my decision to have this system installed.

 

[ABMax24]

My system is still operating well, June has been the best month ever for production with the clear weather we've had. I still haven't quite broke even for the year yet though, which in the past has normally occurred in early June. I already know I'll make less this year than I'll use, just not sure exactly how much, last year I was 5% short but I think 10% short this year is a reasonable guess. Adding central AC last year and now with the wife at home full time our consumption has increased.

I'm still not regretting the decision to install these, the only issue I've had so far is a couple pigeons tried to nest under the panels last spring, but between the summer heat and a crow eating their eggs they left. If it were an issue again I'd have mesh installed around the panels to keep the birds out. My parents have also decided to install a 4.5kw Ground Mount system that should be complete in the next couple weeks, I might be able to snap some pictures of this as well.

 

[ctd]

What size generator would you recommend for it? I plan on pole mounting the panels low enough so I can blow them off with a leaf blower in the winter, and adjust their angle that should help. I really don't want to grid-tie anything. We are trying to build a property that does not rely on the grid for anything, as much as possible anyways

I used to think this way as well, until I started working with solar on our recreational property. Summer is easy, if you are located where the sun shines in the winter then possibly solar.....I'm not.

The big factor would be the cost to bring power onto your property vs solar. My thought process after my RV & recreational property training would be to bring power onto the property. Focus on energy efficient, easy to heat & cool. Then major back that would run the property.....most likely propane so as not to worry about extended no run periods, fuel quality etc.

 

[ctd]

We usually run 10,000 kubota diesels. This way when the geny is on and charging at 100% you still have enough capacity to run anything in your house without the inverter kicking out the charger every time a load comes on like a water pump or the fridge pump kicking on. If you can run a propane fridge or natural gas if it’s available to you. That keeps a lot of load off he system. My water pump is one of my biggest draws so I installed 2 large capacity pressure tanks so when the pump does come on it runs a long time to stop the inrush draw. I get appx 30gallons of draw before the pump starts again. Also install a auto generator start module so you don’t need to always be paying attention. If you watch your consumption it’s very easy to be off grid but it is very costly compared to grid power if it’s easily available. We have been switching back to the lead acid batteries from the AGM now as they seem to last longer and you can equalize them and bring them back where the AGM there is nothing you can do. Lead acid is way cheaper per amp hour but the maintenance must be done on them. Also make sure your grounding is really good. If you have any kind of power issue it can fry a lot of your system.

We upgraded our RV this year, on a recreational property & solar powered. I went with lithium as the cost has come down dramatically

I was always AGM previously, did not want the LA maintenace program. My AGM's failed this year, Concord Lifeline that were 8 years old.

My rationial was cycle time, many more than AGM or LA. Unfortunately I have to wait another 8 years to verify the cool part is the built in bluetooth BMS tracks this as well as charge/discharge. I'm learning things about batteries that I did not know because I'm individually monitoring.

Then there is the near 100% discharge ability with no consequence. The ability to recharge quickly, this would be important running the generator. I'm also getting older so the weight thing is starting to matter, my 200ah lithium battery is lighter than the 225ah Concord. I have 200ah usable vs the 110ah usable from the AGM.

The down side to lithium is you charge below 0*C, that may or may not be an issue. However you place them anywhere such as in the house.

 

[ctd]

Best bet is to get a pole mount with adjustable elevation angle. Adjusting your panels to the correct angle in winter will not only optimize solar collection, but will minimize or eliminate snow buildup as well.

I have remote tower sites that are solar powered that never need attention. The array is mounted nearly vertical though which is not optimal for summer. In my case, the array is sized to run the load during winter months, so even at a 20% efficiency reduction in the summer, the batteries hardly drop below a full state of charge.

You make a point that has always bothered me, drives me crazy when I see panels mounted on a roof. I'm in a high snow load area, why would you install the array on a roof? Near vertical such as the wall, wouldn't that be wiser?

Days are long in the summer with plenty of sunshine, so the panel is not optimal.......who cares. Certainly not the batteries. Design the solar system for best winter performance & it will perform just fine in the summer.

 

[ABMax24]

You make a point that has always bothered me, drives me crazy when I see panels mounted on a roof. I'm in a high snow load area, why would you install the array on a roof? Near vertical such as the wall, wouldn't that be wiser?

Days are long in the summer with plenty of sunshine, so the panel is not optimal.......who cares. Certainly not the batteries. Design the solar system for best winter performance & it will perform just fine in the summer.

Most systems are grid tied, the largest financial benefit in that case usually comes from maximizing annual production even if that comes at the cost of lower winter production. My panels are roof mounted because I don't want then taking up my limited yard space, and wall mount suffers a large loss of production.

Ideally a 2-axis tracker would be used and would give the best output in all scenarios, including allow the array to tilt vertical to dump the snow off in the winter. Except that they cost 2-3x more than the panels and inverters combined.

My parents are going with a different theory though, their ground mount should be accessible enough to clear the snow from the panels in the winter.

 

[X-it]

Make dam sure you access your attic during a heavy rain storm or a spring thaw to check for roof leaks. If you have leaks it will be a challenge to mitigate, but leaving it will turn out far worse. Shingles do not make anywhere near the time they quote you. 20 years would be a good average for most. Not sure how efficent the solar panels after that length of time.

 

[rsaint]

Most systems are grid tied, the largest financial benefit in that case usually comes from maximizing annual production even if that comes at the cost of lower winter production. My panels are roof mounted because I don't want then taking up my limited yard space, and wall mount suffers a large loss of production.

Ideally a 2-axis tracker would be used and would give the best output in all scenarios, including allow the array to tilt vertical to dump the snow off in the winter. Except that they cost 2-3x more than the panels and inverters combined.

My parents are going with a different theory though, their ground mount should be accessible enough to clear the snow from the panels in the winter.

I am also looking at ground mount 10kw system but bifacial set up as a fence running north south but having design issues the way our electrical is set up with backup generator

 

[lilduke]

With the grid tied system, if the power company power went out, but it is a sunny day, do you still have power? Or how does that work.

 

[Dawizman]

With the grid tied system, if the power company power went out, but it is a sunny day, do you still have power? Or how does that work.

Code requires that a grid tied system shuts down in the event of a grid outage.

 

[lilduke]

Code requires that a grid tied system shuts down in the event of a grid outage.

Shitty.

 

[ABMax24]

Yes and no. My system shuts off when the grid power does.

There are systems though that incorporate a battery and can run in off grid mode while the power is out. A Tesla Powerwall could enable this, I believe Solaredge and Fronius both offer backup options for power outages as well. Of course there needs to be a transfer switch of sorts to disconnect the house from the grid.

Personally I'd wait a bit before installing one with outage backup though, the technology is just becoming more common place and options will only increase in the coming years.

 

[lilduke]

Wonder what batteries last longer.( In years of service i mean.)

Tesla wall (lithium) or old school deep cycle batteries. Lithium are kinda expensive?

 

[ABMax24]

Lithium hands down, especially some of the new battery chemistries coming out. Cycle life is much higher too.

That being said lead acid has it's place, especially for backup if the batteries only get cycled a handful of times per year. Most deep cycles also die an early death due to poor treatment. 90% of people don't even know to check the electrolyte level and top up with distilled water as needed, and that's pretty simple. Never mind Bulk, Absorption, or float voltages, or temperature/voltage coefficients. 10 year life on an off grid set of lead acid batteries is possible.

Lithium is simple, the BMS takes care of all that, and the cells themselves don't require maintanance.