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Home Solar

Romer

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Hey @Romer do you have new daily stats for us yet???? I'm waiting over here on the edge of my seat to see how your system performed yesterday!
Yeah, about that. I think I have taken enough of the thread with my system. I did want a full 24 hours with Batteries so that is done.
I must have confused you with someone else in this thread who DIYd. Curious how much power you are making if any today with the snow.
Not much :) Marco rover67 did his own build
 

gungriffin

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@Romer it is pretty cool to see how well this system is working for you! How many Sq ft is your house? Wasn't it possible to run your AC off of your solar setup?

On a different note, I am starting to suspect that the most fun way to do this is to just go off grid with a larger battery bank, or go with a few 6000-8000w inverters compatible with a 48v battery that probably won't do grid feed (allow the meter to spin in the opposite direction). I have found that it is easily possible to buy ready built 48v batteries for $1500-$1750 per 5.12kwh unit. Also, those batteries can discharge at 100 amps per module at 48v and are rated for 7000 discharges to 80% DOD. Couple that with a decent number of panels and it would be easy to be all set. This is what I plan to do at my new house IF we plan to be there more than a few years. The only major advantage to getting credits from Xcel is just to offset a gas bill. As I understand it, there is not much or any cash value to the credits.

Batteries:
https://www.signaturesolar.us/products/48v-100ah-lcd-battery-by-eg4 (they usually sell the less expensive cells without the LCD screen for $1500)
or
Something DIY with used cells like @J1000 with some Leaf Cells

with

or
 

Romer

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@Romer it is pretty cool to see how well this system is working for you! How many Sq ft is your house? Wasn't it possible to run your AC off of your solar setup?
My house is about 5500 sg ft finished. Its winter so haven't run the AC, but based on plots from Xcel on usage and projected summer performance, it shouldn't be an issue
 

nakman

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Hey @Romer do you have new daily stats for us yet???? I'm waiting over here on the edge of my seat to see how your system performed yesterday!
Homer-yells-nerd.gif
 

Shuksan

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Denver
@Romer it is pretty cool to see how well this system is working for you! How many Sq ft is your house? Wasn't it possible to run your AC off of your solar setup?

On a different note, I am starting to suspect that the most fun way to do this is to just go off grid with a larger battery bank, or go with a few 6000-8000w inverters compatible with a 48v battery that probably won't do grid feed (allow the meter to spin in the opposite direction). I have found that it is easily possible to buy ready built 48v batteries for $1500-$1750 per 5.12kwh unit. Also, those batteries can discharge at 100 amps per module at 48v and are rated for 7000 discharges to 80% DOD. Couple that with a decent number of panels and it would be easy to be all set. This is what I plan to do at my new house IF we plan to be there more than a few years. The only major advantage to getting credits from Xcel is just to offset a gas bill. As I understand it, there is not much or any cash value to the credits.

Batteries:
https://www.signaturesolar.us/products/48v-100ah-lcd-battery-by-eg4 (they usually sell the less expensive cells without the LCD screen for $1500)
or
Something DIY with used cells like @J1000 with some Leaf Cells

with

or
This is what I would like to do, but need to do a bit more research on it. One issue is allot of our appliances are gas, which I would like to switch to electric if we did a big solar investment.
 

RayRay27

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I just have solar, no batteries, and I can run my AC full blast in the summer time (70ºF all day) plus running all of our normal electrical items, washer, dryer, dishwasher, tv's, ect, ect, ect, ect and I didn't have to pay an electric bill from June through October. I was averaging over 1100 kWh June through August.

1643211304585.png

I was skeptical about installing solar because I heard some really crazy horror stories and it was hard to justify the cost vs. re-coup factor but after seeing what the system produces over a full year I can say that I have easily saved over 1200 bucks. This may not be enough for some to justify but its nice not having to pay an electric bill the entire summer.
 

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gungriffin

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This is what I would like to do, but need to do a bit more research on it. One issue is allot of our appliances are gas, which I would like to switch to electric if we did a big solar investment.

If I was confident that I would be in my present house for at least 10 years, this is what I would do. Right now my water heater and furnace are gas. I am pretty sure that the 8 year old gas water heater is starting to go bad. This makes sense as the previous owner of the house always chose the cheapest option available. I am thinking about switching to one of those fancy heat pump water heaters. In the summer it will act like an AC unit for the basement and in the winter it can be set to being a normal 4500w water heater. When the 20 year old gas furnace goes bad I will probably switch it out for a heat pump for solar as well. I can just keep an extra space heater or two around for the days when it gets super cold. I just wish it was easier to find a decent UL listed inverter that allowed for grid tie and also 48v batteries that was reasonably priced.

I just have solar, no batteries, and I can run my AC full blast in the summer time (70ºF all day) plus running all of our normal electrical items, washer, dryer, dishwasher, tv's, ect, ect, ect, ect and I didn't have to pay an electric bill from June through October. I was averaging over 1100 kWh June through August.

View attachment 101426
I was skeptical about installing solar because I heard some really crazy horror stories and it was hard to justify the cost vs. re-coup factor but after seeing what the system produces over a full year I can say that I have easily saved over 1200 bucks. This may not be enough for some to justify but its nice not having to pay an electric bill the entire summer.
How many watts is your panel array?

I think that many people still believe the payback is 20 years like it was in the 1990s. It has definitely gotten much lower since then. Most people around Colorado can get the solar paid off in 5-10 years depending on options and tax credits. That is pretty awesome when the lifespan on many of these panels is pushing 30 years now. I also don't think that energy will be getting less expensive in the next 2-4 years which would only make the payoff period lower. When I was looking at moving to Puerto Rico, the payback on a self install full battery system was as low as 3 years! This was an excellent option as the power goes out all the time there. PR's electrical grid is muy mal.
 

RayRay27

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If I was confident that I would be in my present house for at least 10 years, this is what I would do. Right now my water heater and furnace are gas. I am pretty sure that the 8 year old gas water heater is starting to go bad. This makes sense as the previous owner of the house always chose the cheapest option available. I am thinking about switching to one of those fancy heat pump water heaters. In the summer it will act like an AC unit for the basement and in the winter it can be set to being a normal 4500w water heater. When the 20 year old gas furnace goes bad I will probably switch it out for a heat pump for solar as well. I can just keep an extra space heater or two around for the days when it gets super cold. I just wish it was easier to find a decent UL listed inverter that allowed for grid tie and also 48v batteries that was reasonably priced.


How many watts is your panel array?

I think that many people still believe the payback is 20 years like it was in the 1990s. It has definitely gotten much lower since then. Most people around Colorado can get the solar paid off in 5-10 years depending on options and tax credits. That is pretty awesome when the lifespan on many of these panels is pushing 30 years now. I also don't think that energy will be getting less expensive in the next 2-4 years which would only make the payoff period lower. When I was looking at moving to Puerto Rico, the payback on a self install full battery system was as low as 3 years! This was an excellent option as the power goes out all the time there. PR's electrical grid is muy mal.
1643215011220.png
 

rover67

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I did do my own install from the main distribution panel to the hardware install on the roof. Installed the meter socket, all the conduit, pulled all the wires, split the house into a new main distribution panel with load center in the house as a sub panel, redid the wiring to the garage and put a sub panel there also, did the inverter and solar panel installs with all the associated racking and conduit, wiring etc. Labor was free and hardware costs were cheap.

Also did a heat pump hot water heater which is located in the basement where it gets it's air intake from the room with the wood stove. Switched the wood stove that we had from the 70's (fisher mama bear) to a new Blaze King with a cat. That literally cut our wood consumption in half. We have electric base board heat on Mysa thermostats as well as two direct vent propane Jotul stoves on Nest thermostats. I use the baseboard heat when we aren't here mainly and along with the propane stoves to preheat when were on our way home from a weekend away for example. The propane stoves also just keep heat up if the wood stove is off. I also spent a lot of time doing air sealing and insulating where I could... this was a challenge since we have a log home but I did get below 3 ACH after the work. Also added an ERV.

Anyways, the 5kw solar setup covers our electrical but we burn 2 cords of wood a year and consume about 300 gallons of propane. The water heater located next to the wood stove kicks ass as it takes excess heat in the winter from that stove and in the summer keeps the house cooler. For us it's a win win... but I will say that is does cool the air a lot so you have to plan for that. Our wood stove burns almost 24/7 in the winter.
 

gungriffin

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I did do my own install from the main distribution panel to the hardware install on the roof. Installed the meter socket, all the conduit, pulled all the wires, split the house into a new main distribution panel with load center in the house as a sub panel, redid the wiring to the garage and put a sub panel there also, did the inverter and solar panel installs with all the associated racking and conduit, wiring etc. Labor was free and hardware costs were cheap.

Also did a heat pump hot water heater which is located in the basement where it gets it's air intake from the room with the wood stove. Switched the wood stove that we had from the 70's (fisher mama bear) to a new Blaze King with a cat. That literally cut our wood consumption in half. We have electric base board heat on Mysa thermostats as well as two direct vent propane Jotul stoves on Nest thermostats. I use the baseboard heat when we aren't here mainly and along with the propane stoves to preheat when were on our way home from a weekend away for example. The propane stoves also just keep heat up if the wood stove is off. I also spent a lot of time doing air sealing and insulating where I could... this was a challenge since we have a log home but I did get below 3 ACH after the work. Also added an ERV.

Anyways, the 5kw solar setup covers our electrical but we burn 2 cords of wood a year and consume about 300 gallons of propane. The water heater located next to the wood stove kicks ass as it takes excess heat in the winter from that stove and in the summer keeps the house cooler. For us it's a win win... but I will say that is does cool the air a lot so you have to plan for that. Our wood stove burns almost 24/7 in the winter.

I had no idea that wood stoves now have catalytic converters. Too cool.

Do you have a grid tie or a battery backup to supplement your solar setup? What model of heat pump water heater did you get?
 

rover67

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Boulder, Co
I did a grid tie setup, we also have a 25kw whole house generator tied to the propane tank that is on an auto switch. It's a little weird because when the power goes out the solar shuts down and the generator kicks on... but it works. We don't loose power that often and when we do we can still do laundry, run the well pump, oven, I can weld (when it snows seems like a plow is always broken) it is truly life as usual. When we moved in the place had the generator so it was an easy decision. If I were starting over again I might do batteries but honestly the generator is super simple and works. I change the oil in it once a year or so that's about it.

The water heater is a Rheem Performance Platinum. It seems to work well. When we have lots of people staying with us (like holidays) I will switch it to high demand mode where it uses resistive elements to keep up like a normal water heater. The water heater for us was a huge draw, so the switch to the heat pump style saves us a ton of kWh every month.

I also installed one of these under our master bathroom, it heats the incoming cold water to the bathroom with waste water from the shower. We don't really run out of hot water.

 

nakman

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Hey help me understand this... the last three days it's been pretty sunny, and I made 26, 28, and 22kwh per day. But when I look at my graphs I appear to be topping out on production right at 1.00 kWh.

IMG_5692.PNG

IMG_5691.PNG

IMG_5690.PNG


It's like I'm hitting a limiter. Is this the most my system will produce? So the only way to produce more than 1.00 is to add panels? Or could there actually be a governor on the system setting the limit? My system is rated at 5,440 watts. but I don't get how that correlates to what I am measuring.
 

rover67

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Usually that happens when the array is oversized for the inverter. what inverter do you have? how many panels and of what wattage? It's not a bad way to design a system and I think harkens to a time when inverters weren't as efficient when they were running at lower than rated power.
 

DaveInDenver

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The graphs look odd to me, too. They seem misleading since there's no instantaneous kW-hr measurement. You have power, which is watts, generated over time. So if 1kW flows constantly for one hour you have generated 1kW-hr.

To get 24 kW-hr per day you need 1 kW generated for 24 hours. But this is impossible of course. So 24 kW-hr per day is generally something like 6 kW for 8 hours midday. So given that reality it makes sense that your 5440 watts would have 26, 28 and 22 kW-hr total generated per day (about 8 hours) in the winter.

Graphs like that would I think be a cumulative or average kW-hr amount of energy made. So it should be either increasing or decreasing as the sun arcs overhead. It can't be exactly flat for several hours.

Maybe it's showing how much energy you're putting into the grid and that is capped at 1kW? Or starting around 9AM your household uses most of the power, e.g. the ~4kW difference is being consumed? It seems too ideally flat for consumption but maybe it's just a fluke that furnace cycling and that sort of thing average out.
 

RayRay27

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Hey help me understand this... the last three days it's been pretty sunny, and I made 26, 28, and 22kwh per day. But when I look at my graphs I appear to be topping out on production right at 1.00 kWh.

View attachment 101570
View attachment 101571
View attachment 101572

It's like I'm hitting a limiter. Is this the most my system will produce? So the only way to produce more than 1.00 is to add panels? Or could there actually be a governor on the system setting the limit? My system is rated at 5,440 watts. but I don't get how that correlates to what I am measuring.
Best thing to do is check your net meter and compare it to the readings on the app. If you are generating power you should be flowing backwards or negative. I do this from time to time to make sure everything is on the up and up.

Do you have a monthly graph or just daily? Curious as to what the monthly or annual graphs look like or how the measurements are determined.
 

Romer

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the graph doesn't make sense to what you say you are producing a day. The flat top is indicative of "clipping" meaning something is at is limit which most likely would be an undersized inverter as stated above

Are you sure that isn't a panel or just a string? If so then that could be that panel or string reaching its normal saturation point which may be OK

you would expect at a system level to have a more bell shaped curve like I posted above.
 

nakman

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Marco: I've got a micro inverter at each panel. 17 panels 320 watts each. even at 50% I should still see double what I am seeing on this graph, right?

Dave: appreciate the comments, and I agree it doesn't seem to add up here. I have asked Project Solar this same question, haven't seen a response I suspect it's getting bounced around internally there.

Ray: How would I check my net meter? the thing on the side of the house? All it does is have little squares that go left to right when I'm consuming power, and right to left when I'm generating it... are you comparing the numbers on the readout?

yeah I can graph a month, or a year. Here's January:

IMG_5693.PNG

So I made 435kWh in 31 days, that's 14 per day. Big difference between the sunny days and cloudy days, no surprise there. But 14x365=5,110, and I have a 5,440 watt system. So this totally adds up to me... once the sun is out for longer that daily average will climb, take a dip again next fall, etc. But maybe I'm getting my units mixed up, still don't know why it would top out like that.

Ken: that graph is the whole array, I don't think I can get indivual graphs on the panels. What I can see though is what each panel does each day? Here is yesterday for example:

IMG_5694.jpg


So the sum of all of those panels is 28.4?
 
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gungriffin

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Aren't each of the bars representing ~15 minute intervals? If so, that comes to about the about correct kWh per per 15 minute interval for your system in the winter right? Then multiply times 4 for each hour equivalent. There are on average about 4.4 sun producing hours per day at the winter solstice and about 5.7 during the summer solstice. The snow/clouds has skewed you lower for the month of January. Your 5.4kw system should be able to produce 5.4kw per sun producing hour assuming 100% efficiency. Your system is probably about 97% efficiency right? So 4.6 (sun hours) x5.44 (kW) x0.97 (efficiency)=~24.27kWh per day on a sunny day right now during winter.

 

RayRay27

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Marco: I've got a micro inverter at each panel. 17 panels 320 watts each. even at 50% I should still see double what I am seeing on this graph, right?

Dave: appreciate the comments, and I agree it doesn't seem to add up here. I have asked Project Solar this same question, haven't seen a response I suspect it's getting bounced around internally there.

Ray: How would I check my net meter? the thing on the side of the house? All it does is have little squares that go left to right when I'm consuming power, and right to left when I'm generating it... are you comparing the numbers on the readout?

yeah I can graph a month, or a year. Here's January:

So I made 435kWh in 31 days, that's 14 per day. Big difference between the sunny days and cloudy days, no surprise there. But 14x365=5,110, and I have a 5,440 watt system. So this totally adds up to me... once the sun is out for longer that daily average will climb, take a dip again next fall, etc. But maybe I'm getting my units mixed up, still don't know why it would top out like that.

Ken: that graph is the whole array, I don't think I can get indivual graphs on the panels. What I can see though is what each panel does each day? Here is yesterday for example:

View attachment 101598

So the sum of all of those panels is 28.4
Iam assuming that your meter has a digital number read out on it plus three little blocks underneath the numbers that move from left to right or visa versa depending on whether your producing energy or not.
pseg_net_meter_long_island-square.jpg


What you can do is go out early in the morning and read the number on the meter then check it again in the afternoon when the sun goes down. Obviously you want to do this on sunny day so you can see if your meter is running backwards or counting down. You can compare this number to what your app is telling you what you're producing.
Personally I think your app may just be acting up. It looks like in your monthly and annual charts are reading correctly.
 

J1000

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Yeah the graph is weird but it looks ok to me. I went cross-eyed counting the lines but it adds up to the KWh produced by your system from what I can tell. It looks like the graph program just makes a new bar once 1 kWh has been produced.
 
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