Seeking to buy/build residential off-grid system

[ajoyce0830]

Hi friends,
We use 8000 Kw annually in our home, and I’m trying to design a cost-effective off-grid system If I understand correctly, we probably need a 6-7kw array. I was going to try to use 2: Nature’s Generator Elite with 2: 6-circuit power transfer switches at the Breaker panel, 60: 100w 12v panels, and a lot of deep cycle lead acid batteries. Alternatively, now that I’m reading about 24v systems with 2: lithium batteries in series, I’m rethinking. Would someone be able to advise me on if I can imitate Will’s mobile systems for a regular residence, or if there is a way to spend 7,000 or less and power our entire home off grid, and what I need to do that? I may be oversimplifying things; though even if I could get away with spending less than $10,000 on this, I’d have spent around $7,000 after the 26% tax credit. I’m open to plug-and-play and diy recommendations. Energy independence, no electric bill, and 5-7 year ROI are the goals.

 

[DASH]

Big difference with the way electricity is delivered and available in a off grid system compared to a on grid system, or getting electric from the power company.

 

[ajoyce0830]

Understandable. I forgot to include charge controller in my list, and I’m also fine with doing a different inverter than the nature’s generator and doing all the work. This way I’d be able to better maintain and fix components overtime. Is this a feasible endeavor and how so?

 

[MisterSandals]

60: 100w 12v panels, and a lot of deep cycle lead acid batteries

Are you torturing yourself on purpose proposing to use 60 tiny panels?
I would look on craigslist or ebay for some big 300w panels. You will be tired of installing and wiring 20 panels.
Santan solar seems to be a name that keeps coming up for big cheap panels too.

Regarding lead acid and an ROI, that will be a continual moving target. Looking ahead, when selecting an SCC, you should consider one that can handle LiFePO4 batteries as well in case you go that way.

Sounds like a fun but daunting project. You should use the search tool on this forum, there are LOTS of great examples to learn from.

 

[Ampster]

We use 8000 Kw annually in our home, and I’m trying to design a cost-effective off-grid system If I understand correctly, we probably need a 6-7kw array.

The correct unit of measure for energy that you consume is kilo Watt hours (kWh). I don't mean to nitpick but that little "h" can mean the difference between thinking you got a great deal to getting ripped off in terms of buying the kind of equipment that you will need to cover your energy needs.
A 6-7kW array sounds about right but it may be useful to check that with a tool such as PVWatts. You may want to oversize your array to account for efficiency losses and/or future needs or weather variations. Or you can design for upgradability.

I was going to try to use 2: Nature’s Generator Elite with 2: 6-circuit power transfer switches at the Breaker panel, 60: 100w 12v panels, and a lot of deep cycle lead acid batteries. Alternatively, now that I’m reading about 24v systems with 2: lithium batteries in series, I’m rethinking. Would someone be able to advise me on if I can imitate Will’s mobile systems for a regular residence, or if there is a way to spend 7,000 or less and power our entire home off grid, and what I need to do that?

Going entirely off grid is more expensive than your budget has allocated, but leveraging a Grid Tie system is possible and you can use the cost savings of that toward purchasing the components to be able to self consume your power as a longer term plan. I can provide examples but first it would be helpful to know if your utility provides net metering?

I may be oversimplifying things; though even if I could get away with spending less than $10,000 on this, I’d have spent around $7,000 after the 26% tax credit. I’m open to plug-and-play and diy recommendations. Energy independence, no electric bill, and 5-7 year ROI are the goals.

If you need a 6 kW system you should be able to DIY a decent grid tie (GT) system for about $2 a Watt or $12,000. Panels should cost $1 a Watt and racking, wiring and inverter(s) should be another $1 a Watt. Look at some of the packages at Wholesale Solar, Renvu and AltE to get your own ball park.
The ROI or number of years payback will depend on the rate you are paying your energy provider and any incentives in the form of Net Energy Metering agreements. You may have to research that or if you are in California several of us are familiar with those plans.

 

[ajoyce0830]

Are you torturing yourself on purpose proposing to use 60 tiny panels?
I would look on craigslist or ebay for some big 300w panels. You will be tired of installing and wiring 20 panels.
Santan solar seems to be a name that keeps coming up for big cheap panels too.

Regarding lead acid and an ROI, that will be a continual moving target. Looking ahead, when selecting an SCC, you should consider one that can handle LiFePO4 batteries as well in case you go that way.

Sounds like a fun but daunting project. You should use the search tool on this forum, there are LOTS of great examples to learn from.

Lol i was very much not looking forward to 60, I think I’ve been trying to force a square peg in a round hole to use the nature’s generator. Up to this point of my learning, 2 LiFePO4 batteries in series for a 24v system seems like a great base to build from, and 20 300w panels is much more desirable. I started making one compromise compounding others forcing myself in the 12v direction, though I’m refreshed to discover 24v and 48v routes.

I’m plotting to build a roof/pergola/canopy over our deck and tilting it south at 45 degrees which should also give us a lot more surface area over the deck for panels and easier to reach for snow removal than our 2-story roof and after that setting up a rain barrel system propped up for pressure and possible connections to our laundry and toilet then irrigation. With all these interconnected features, I just really wanna start with a scalable solar setup that wont flop and need redone

 

[ajoyce0830]

Lol i was very much not looking forward to 60, I think I’ve been trying to force a square peg in a round hole to use the nature’s generator. Up to this point of my learning, 2 LiFePO4 batteries in series for a 24v system seems like a great base to build from, and 20 300w panels is much more desirable. I started making one compromise compounding others forcing myself in the 12v direction, though I’m refreshed to discover 24v and 48v routes.

I’m plotting to build a roof/pergola/canopy over our deck and tilting it south at 45 degrees which should also give us a lot more surface area over the deck for panels and easier to reach for snow removal than our 2-story roof and after that setting up a rain barrel system propped up for pressure and possible connections to our laundry and toilet then irrigation. With all these interconnected features, I just really wanna start with a scalable solar setup that wont flop and need redone

The 45 degrees is conveniently pretty close to our 41 degree latitude and an easy measurement to miter cut the wood framing

 

[Ampster]

..............
I’m plotting to build a roof/pergola/canopy over our deck and tilting it south at 45 degrees which should also give us a lot more surface area over the deck for panels and easier to reach for snow removal than our 2-story roof and after that setting up a rain barrel system propped up for pressure and possible connections to our laundry and toilet then irrigation. With all these interconnected features, I just really wanna start with a scalable solar setup that wont flop and need redone

Great idea. I did a west facing one last year. In my jurisdiction you don't need a building permit for the canopy but I built it strong enough for the calculations of the solar panel loads so my permit would go smoother. Speaking of loads. I don't get snow so the loads are uplift but in your neck of the woods it would be snow loads. The thing I also loved about the patio cover is that hooking up the panels from below was a whole lot easier. I also decided to add optimizers/microinverters because of shade and that was much easier too because of the access from below and not having to move the panels.
Another issue that you might encounter if you are pulling a permit is that some jurisdictions have adopted the latest NEC guidelines about Rapid Shut Down. That usually only applies to roofs because it is for the protection of firefighters who might need to go on your roof to fight a fire, but it should not apply to canopies which is another advantage of your plan. Those requirements can add $50-100 cost to each panel for the RSD equipment. That gives you a wider choice of GT string inverters which always helps the budget.

 

[ajoyce0830]

Great idea. I did a west facing one last year. In my jurisdiction you don't need a building permit for the canopy but I built it strong enough for the calculations of the solar panel loads so my permit would go smoother. Speaking of loads. I don't get snow so the loads are uplift but in your neck of the woods it would be snow loads. The thing I also loved about the patio cover is that hooking up the panels from below was a whole lot easier. I also decided to add optimizers/microinverters because of shade and that was much easier too because of the access from below and not having to move the panels.
Another issue that you might encounter if you are pulling a permit is that some jurisdictions have adopted the latest NEC guidelines about Rapid Shut Down. That usually only applies to roofs because it is for the protection of firefighters who might need to go on your roof to fight a fire, but it should not apply to canopies which is another advantage of your plan. Those requirements can add $50-100 cost to each panel for the RSD equipment. That gives you a wider choice of GT string inverters which always helps the budget.

Right on! Would you be so kind to explain the use of optimizers/microinverters? I’m not familiar with these.

 

[Ampster]

Right on! Would you be so kind to explain the use of optimizers/microinverters? I’m not familiar with these.

Optimizers are typically used on Solaredge systems. They provide the advantages that one gets from microinverters if there is shade.That advantage is that if one panel gets shaded, it can reduce the output of the entire string. The difference between microinverters and optimizers is that with an optimizer, there is still the need for a string inverter. In the case of a microinverter it is the inverter as well. Micro inverters start becoming expensive for large systems because the economies of scale using one $1500 string inverter for 20 panels is a lot less expensive than spending $100 each for 20 micro inverters. Microinverters are an easy way to add incremental capacity. For example I had a 5.7 kW system professionally installed because I am too old to want to work all day on my single story roof that has a fairly steep pitch. After about a year I decided I wanted some more capacity and that is when I built the patio cover and bought some used panels. I put 4 panels on my patio cover with micro inverters which was a whole lot less expensive than calling up my installer and asking them to install four panels. I ran a 240 volt AC line on a separate circuit to a junction box under my patio cover and connected the microinverter cable to that and I was done.

 

[ajoyce0830]

I’d love to build a 5.7kw system like yours and mount the panels on the to-be roof of my 20 foot by 12 foot deck. I imagine there will be much more squarefootage with the 45 degree canopy tilt, though I’ll have the remember the trigonometry formula. Would you recommend your system and provide the details?

 

[Ampster]

The simple 45 degree isosceles triangle that I remember from geometry is the hypotenue is 1.41
times the leg. I have had a few occasions to revisit that which is the only reason I can remember something like that from 60 years ago.

I will give you an overview so you can see where I was going with my earlier thoughts about a long term plan for self consumption.
Some background. I drive two EVs and some people have called me a member of the Green Mafia, whatever that is. I have lived in California all my life and recently bought a home in the wine country of Sonoma County. Shortly after moving to this home two years ago I had a 5.7 kW Grid Tie system installed. Electric rates are crazy high in California and the utilities do not want to lose revenue so 5.7 was the largest system they would allow me to build. I have no shade but Rapid Shut Down safety requirements do apply so a Solaredge system with Korean Qpanels was installed. The Q panels are a good quality commodity panel.

Once I got settled in to that home I began planning the next phases. It came together quicker when we realized that the back of the house and patio were hot because of the afternoon sun so the patio cover was built. I got a deal on some used panels enough to provide some shade and I hooked up four of them up to micro inverters. The others just provided shade until I could start on the next phase.

That phase involved installing a bimodal hybrid inverter that would allow further expansion and not require further permission from my utility. The beauty of a bimodal hybrid inverter is that it can operate entirely off the grid but use grid power to supplement loads when necessary. It doesn't need batteries but it has some expansion capabilities that I can go into in more detail as this conversation progresses. That is where batteries come in and self consumption can become more of a reality.

 

[ajoyce0830]

What do you think of the MPP LV5048 with https://bigbattery.com/product/48v-li-ion-powerwall/ref/8/?
I also thought about using chevy volt batteries and trading my gas gar for a chevy volt

 

[ajoyce0830]

What do you think of the MPP LV5048 with https://bigbattery.com/product/48v-li-ion-powerwall/ref/8/?
I also thought about using chevy volt batteries and trading my gas gar for a chevy volt

Or nissan leaf etc

 

[Ampster]

What do you think of the MPP LV5048 with https://bigbattery.com/product/48v-li-ion-powerwall/ref/8/?
I also thought about using chevy volt batteries and trading my gas gar for a chevy volt

It depends on your long term strategy. I don't know much about the MP LV5048. I purchased an Outback Skybox and love it. The features that were important to me were:
UL certified.
AC coupling to leverage my existing Grid Tie system
TOU and grid zero modes
Manufacturer support.
All in One- transfer switch, MPPT, programmable charger,

I purchased part of a Volt battery for a system in another home. They are rugged but hard to configure into larger packs. At that time multiple BMSs were expensive so the thought of lots of parallel 48 volt packs was going to be expensive. I sold it and went in the direction of used Nissan Leaf packs. That was 2016
I leased a Chevy volt and it was a good car for that time. It like any hybrid is extremely complex because has components of an EV, and internal combustion engine and all the things necessary to integrate to two. I now have two EVs with 120,000 miles on them collectively and they are very simple. No oil changes, brake pads last a long time, no waiting in lines for gas, quiet, lots of torque, very little maintenance, constant over the air enhancements and the list goes on.

Or nissan leaf etc

I have used that Leaf pack for 4 years now and it is showing its age. I just committed to by 28 kWh of LFP from China for less that the cost of incrementally increasing my Leaf pack. I will be selling the 54 Leaf modules in the next 60-90 days.

 

[solarfather]

Great idea. I did a west facing one last year. In my jurisdiction you don't need a building permit for the canopy but I built it strong enough for the calculations of the solar panel loads so my permit would go smoother. Speaking of loads. I don't get snow so the loads are uplift but in your neck of the woods it would be snow loads. The thing I also loved about the patio cover is that hooking up the panels from below was a whole lot easier. I also decided to add optimizers/microinverters because of shade and that was much easier too because of the access from below and not having to move the panels.
Another issue that you might encounter if you are pulling a permit is that some jurisdictions have adopted the latest NEC guidelines about Rapid Shut Down. That usually only applies to roofs because it is for the protection of firefighters who might need to go on your roof to fight a fire, but it should not apply to canopies which is another advantage of your plan. Those requirements can add $50-100 cost to each panel for the RSD equipment. That gives you a wider choice of GT string inverters which always helps the budget.

Sorry to jump in here, but a side question, how does one find out if a permit is required for a canopy install (or what kind of installs require permitting)? I tried a quick search, but not really sure what I'm looking for and where for my area. Is this usually only for grid-tie or does off grid also sometimes require permitting?

 

[ajoyce0830]

Sorry to jump in here, but a side question, how does one find out if a permit is required for a canopy install (or what kind of installs require permitting)? I tried a quick search, but not really sure what I'm looking for and where for my area. Is this usually only for grid-tie or does off grid also sometimes require permitting?

I just googled my township then solar permit which took me to the city website. Then i pressed control+f to use the find/search function to skip to each part of their page that had the word “solar”

 

[Ampster]

Sorry to jump in here, but a side question, how does one find out if a permit is required for a canopy install (or what kind of installs require permitting)? I tried a quick search, but not really sure what I'm looking fo 1r and where for my area. Is this usually only for grid-tie or does off grid also sometimes require permitting?

The two jurisdictions that I have had experience with require a permit for any electric circuits. My canopy did not require a permit but the solar I installed on it had to be approved as part of the permit for inverter.