# what a difference a month makes



## Woodsplitter67 (Mar 9, 2021)

February was a terrible month for solar production.  I had 10 days with basically no production. The snow sat on my panels for days and there were days it was so overcast that production was like 10kw. March rolls in and I have like 6 days at 70kw or close to in production.. My credit I was running was small and my production was terrible so I'm pretty sure I'm going to have my first electric bill in a long time..


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## Brian26 (Mar 9, 2021)

Same here in CT.  I'm already over my February production after the first 8 days of March.


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## jetsam (Mar 9, 2021)

I'm 50kwh away from beating Feb, 9 days into March.  It was a wintery February!


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## stoveliker (Mar 9, 2021)

Same here; I only have a 7.2 kW system (2 sets of LG panels, ridgeline of the roof runs N/S, but it meets my needs  and more, including minisplit heat when it's 35 F or higher, making about 500-1000 kWh more each year so far than I need, long live net-metering w/o reconciliation...), but yesterday I beat February too.

Last year's February was 349 kWh. This year less than half that at 153. March has 162  already.


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## Solarguy3500 (Mar 9, 2021)

I actually had a decent February with 640 kWh, but only because I religiously cleaned the snow off the panels after every storm, and there were quite a few storms in February.

I was on track for a stellar March until my inverter failure on Saturday morning.  Already had 250 kWh in only 5 days. It has been killing me to look out the window these last few perfect solar days knowing I'm producing nothing.  I hope SolarEdge sends that new inverter out pretty quick.


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## stoveliker (Mar 9, 2021)

Ugh. My panels are too high, and the hill sloping away from the home too steep to get a sweep up there to get the snow off.

But man, many of you make a lot of kWhs... I made 6300 last year, and that was 1500 more than I used...

Regardless, it's nice to be flush in free kWhs, I hope that inverter come soon!  (But better that it failed now than in July...)


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## Solarguy3500 (Mar 9, 2021)

stoveliker said:


> Ugh. My panels are too high, and the hill sloping away from the home too steep to get a sweep up there to get the snow off.
> 
> But man, many of you make a lot of kWhs... I made 6300 last year, and that was 1500 more than I used...
> 
> Regardless, it's nice to be flush in free kWhs, I hope that inverter come soon!  (But better that it failed now than in July...)



Yeah, it's a chore cleaning the snow off, but at least I can do it relatively safely without actually going on the roof (metal). I got one of those soft foam Snowbrum things from the auto parts store made for cleaning snow off cars without scratching the paint. 

The handle wasn't long enough to reach the panels higher up on the roof, so I went to the hardware store and found an extension pole that I think is meant for changing light bulbs in high cathedral ceilings. It has 2 sections for a total of 16' of extension and the end just so happens to have the same thread as the head from the Snowbrum. I can reach all the panels from a ladder at the eave of the roof, and just need to move the ladder once per side of the roof to get all the panels.


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## stoveliker (Mar 9, 2021)

22 ft straight up to the gutter here...


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## ABMax24 (Mar 9, 2021)

I'm envious of all your winter production. Granted I can't clear snow in the winter from mine either, I'm about 25ft to my eaves, but here's my production this year:

But summer makes up for it, in June my panels power up at 6:00am, and don't quit until 10:00pm.


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## jetsam (Mar 9, 2021)

stoveliker said:


> Ugh. My panels are too high, and the hill sloping away from the home too steep to get a sweep up there to get the snow off.
> 
> But man, many of you make a lot of kWhs... I made 6300 last year, and that was 1500 more than I used...
> 
> Regardless, it's nice to be flush in free kWhs, I hope that inverter come soon!  (But better that it failed now than in July...)



Did your installer work hard to bargain you down to a smaller array too?

They wanted to do a 5kw system. I told them I was adding two electric cars and electric heat and electric air conditioning and
an electric stove and dryer and an electric water heater and 500kw of hot tubs and swimming pools and neon signage (well, part of that, anyway). They talked me down to 7kw and said that the paperwork for the tax credit absolutely couldn't be fiddled any more than that.

So they did Maximum Dishonesty with the variance request thingy, and I still got a system that is smaller than what I use before the hypothetical HVAC and electric car...

I think that system needs to be burned down and rethought!  It really feels like they're using the solar tax credit to shoehorn people into burning oil. (You're of course free to walk away from the tax credit, but I doubt there's many takers for that option.)


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## Brian26 (Mar 10, 2021)

jetsam said:


> Did your installer work hard to bargain you down to a smaller array too?
> 
> They wanted to do a 5kw system. I told them I was adding two electric cars and electric heat and electric air conditioning and
> an electric stove and dryer and an electric water heater and 500kw of hot tubs and swimming pools and neon signage (well, part of that, anyway). They talked me down to 7kw and said that the paperwork for the tax credit absolutely couldn't be fiddled any more than that.
> ...



When I had my 5.4 kw system installed 4 years ago in CT I couldn't size it more than my previous years electricity usage. That is a really common requirement with most utilities.


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## Woodsplitter67 (Mar 10, 2021)

Solarguy3500 said:


> I actually had a decent February with 640 kWh, but only because I religiously cleaned the snow off the panels after every storm, and there were quite a few storms in February.
> 
> I was on track for a stellar March until my inverter failure on Saturday morning.  Already had 250 kWh in only 5 days. It has been killing me to look out the window these last few perfect solar days knowing I'm producing nothing.  I hope SolarEdge sends that new inverter out pretty quick.



Are you happy with solar edge.. Have you had any issues with them..or the gear.


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## Woodsplitter67 (Mar 10, 2021)

my 9 day average.. 3/2  to 3/10 is 61.77 kw per day....  the 1st it rained  and was only 15kw..  Got my electric bill today.. and well that sucked.. over 200 bucks.. 
Got some more sunny days ahead of us..


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## Solarguy3500 (Mar 10, 2021)

Woodsplitter67 said:


> Are you happy with solar edge.. Have you had any issues with them..or the gear.



Well, until my inverter failed on Saturday, I personally had not had any problems with Solaredge. I had a system installed at my previous house in 2017 with a Solaredge 7600A inverter and I had no problems with it in the 2 years until we sold the house in 2019. I like the SE monitoring platform, it's easy to use and understand.

From the standpoint of someone who works in the solar business, I can say that in the past few years, I have seen the failure rate on SE inverters tick up. When I first started working in the solar business in 2012, many installers were using Enphase microinverters, some exclusively. A few years later, installers were noticing a high failure rate with the M series micros and everyone switched to Solaredge. During that time and the years that followed up to the present, Solaredge experienced a period of rapid growth, and that's when I started noticing the failure rate of SE inverters start to increase. Now, the pendulum is swinging back the other way and many installers (my employer included) are starting to use the new Enphase IQ series micros which seem to be pretty robust so far.


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## Woodsplitter67 (Mar 11, 2021)

Solarguy3500 said:


> Well, until my inverter failed on Saturday, I personally had not had any problems with Solaredge. I had a system installed at my previous house in 2017 with a Solaredge 7600A inverter and I had no problems with it in the 2 years until we sold the house in 2019. I like the SE monitoring platform, it's easy to use and understand.
> 
> From the standpoint of someone who works in the solar business, I can say that in the past few years, I have seen the failure rate on SE inverters tick up. When I first started working in the solar business in 2012, many installers were using Enphase microinverters, some exclusively. A few years later, installers were noticing a high failure rate with the M series micros and everyone switched to Solaredge. During that time and the years that followed up to the present, Solaredge experienced a period of rapid growth, and that's when I started noticing the failure rate of SE inverters start to increase. Now, the pendulum is swinging back the other way and many installers (my employer included) are starting to use the new Enphase IQ series micros which seem to be pretty robust so far.


ok.. thanks for the information.. really appreciate it


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## DBoon (Mar 12, 2021)

Mid-November to mid-February downwind of the Great Lakes in Central NY can be a pretty  brutal time for solar production. On average, I probably get about 400 kWh/month off a 15 kW array during that period. There are days when it is really cloudy or rainy and I only get 2 or 3 kWh of production. The last week of February and early March with snow on the ground I am getting some 100 kWh days with the sun reflecting off the snow onto the panels. If I optimized by tilt angle a little more I could probably do a little better this time of year, but on the 10 kW of panels with adjustable tilt, I like to keep the panels at 50 degrees from vertical to avoid snow accumulations. I usually change the tilt angle in mid-March. 

I went from 5 to 15 kWh about 1-1/2 years ago. I had used about 5-6 MWh per year for heating (pretty much 100% of my previous production). I told the installer that I was still renovating the house, would be adding about 5-6 MWh of base house load (all-electric kitchen, electric hot water heater, etc.) and one electric car, likely a 2nd electric car a couple years down the road and that was enough to justify the bigger array with full net-metering.  I added to the array at that time because NY net-metering was going to be going away at the end of that year (it was since extended by a year). So I guess my installer did a good job of filing the paperwork and justifying the system size. 

This year, I'll be giving about 12 MWh back (still in renovation mode on the house). When occupied, I'll probably return about 3 MWh until I get the 2nd electric car. If I use my wood stove a lot instead of the geothermal radiant heat, I might be returning a couple MWh more.


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## Brian26 (Mar 12, 2021)

DBoon said:


> Mid-November to mid-February downwind of the Great Lakes in Central NY can be a pretty  brutal time for solar production. On average, I probably get about 400 kWh/month off a 15 kW array during that period. There are days when it is really cloudy or rainy and I only get 2 or 3 kWh of production. The last week of February and early March with snow on the ground I am getting some 100 kWh days with the sun reflecting off the snow onto the panels. If I optimized by tilt angle a little more I could probably do a little better this time of year, but on the 10 kW of panels with adjustable tilt, I like to keep the panels at 50 degrees from vertical to avoid snow accumulations. I usually change the tilt angle in mid-March.
> 
> I went from 5 to 15 kWh about 1-1/2 years ago. I had used about 5-6 MWh per year for heating (pretty much 100% of my previous production). I told the installer that I was still renovating the house, would be adding about 5-6 MWh of base house load (all-electric kitchen, electric hot water heater, etc.) and one electric car, likely a 2nd electric car a couple years down the road and that was enough to justify the bigger array with full net-metering.  I added to the array at that time because NY net-metering was going to be going away at the end of that year (it was since extended by a year). So I guess my installer did a good job of filing the paperwork and justifying the system size.
> 
> This year, I'll be giving about 12 MWh back (still in renovation mode on the house). When occupied, I'll probably return about 3 MWh until I get the 2nd electric car. If I use my wood stove a lot instead of the geothermal radiant heat, I might be returning a couple MWh more.



How much does your utility pay for excess production? Here in CT they pay really low wholesale prices for excess at like .05 kwh. 

Also, your lucky your installer was able to add the extra panels. Here in CT and most of New England your only allowed to size your system off the last year of usage.


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## Solarguy3500 (Mar 12, 2021)

Back in business! My new inverter got installed this morning so I'm up and running again.

Too bad I had to miss out on a week of the best solar weather so far this year.

On the plus side, my solar hot water system was working really well this week and greatly reduced the electric usage from the water heater, which is my largest consumer of electricity by far.


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## DBoon (Mar 13, 2021)

Brian26 said:


> How much does your utility pay for excess production? Here in CT they pay really low wholesale prices for excess at like .05 kwh.


The first year (~2014) when I had a 5 kW system I was paid about 6 cents/kWh. Its been close to 2 cents/kWh every year since then. I'm not going to make money on the excess production, that's for sure. I did want to lock in the 20 year net-metering dealer the larger array, which is why I put it in when I did. NY net-metering is grandfathered for existing installs in 2020 or later (since moved to end of 2021, I think). But after 20 years, net-metering will be replaced in grandfathered systems with a value of solar approach. 



Brian26 said:


> Also, your lucky your installer was able to add the extra panels. Here in CT and most of New England your only allowed to size your system off the last year of usage.


I was frankly shocked it went through with the NY state incentives. I'll be using close to my full production in 2022 and later, and until then I'm basically giving free power back to the grid, so it's not a great deal for me until I start using it. But in my application I explained that it was a house under renovation and the solar was basically used just for heating (which consumed all of the 6 MWh yearly production, and then some in the last year before upgrade), that I would be adding 600-700 kWh of domestic (non-heating) load per month (7.2 to 8.4 MWh per year), and 5 or so MWh per year for an electric car (20,000 miles per year at 4 miles/kWh). So that added up to 18 MWh a year or so - estimated panel production for my 15 kW proposal - and it was approved.


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## NoGoodAtScreenNames (Mar 15, 2021)

Today was my best production day ever. My long experience with solar goes all the way back to July. I was expecting March to be like September based on distance from the solstice but so far March is kicking butt - not just having more sunny days but a sunny day is getting me more than in any of my prior months. I’m thinking the light shading I get is better with no leaves on the trees but I really didn’t expect a good March day to beat a good August day. Maybe the lower temps are the difference?


I have a slightly oversized array for my inverter. Installer said to expect some clipping on really good days. This is the first week I’m noticing that happen. That’s a good problem to have I guess.


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## stoveliker (Mar 15, 2021)

NoGoodAtScreenNames said:


> Today was my best production day ever. My long experience with solar goes all the way back to July. I was expecting March to be like September based on distance from the solstice but so far March is kicking butt - not just having more sunny days but a sunny day is getting me more than in any of my prior months. I’m thinking the light shading I get is better with no leaves on the trees but I really didn’t expect a good March day to beat a good August day. Maybe the lower temps are the difference?
> 
> 
> I have a slightly oversized array for my inverter. Installer said to expect some clipping on really good days. This is the first week I’m noticing that happen. That’s a good problem to have I guess.
> ...



Nice!

That clipping is new to me. Is that because you don't have a mini inverter per panel but one that services all panels?

March has been good to me, but because my panels face East and West, summer is better as the angle is higher for me then. Trees do help some, but not (for me) with the peak max power; they just clip some production early morning and late in the afternoon.


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## NoGoodAtScreenNames (Mar 15, 2021)

stoveliker said:


> Nice!
> 
> That clipping is new to me. Is that because you don't have a mini inverter per panel but one that services all panels?
> 
> March has been good to me, but because my panels face East and West, summer is better as the angle is higher for me then. Trees do help some, but not (for me) with the peak max power; they just clip some production early morning and late in the afternoon.



Yes. I have an 11kw max rated output with a single 10kw capacity Solar Edge inverter. I think the clipping / under sizing the inverter is fairly common since you rarely hit the peak potential output. I’ll let other more knowledgeable folks chime in on whether that’s good or bad. It was common in all the quotes I received so I never questioned it at the time. When picking the inverter he said the only drawback was that it wouldn’t allow adding new panels down the road. That wasn’t a concern since it’s already an above average array size and the roof is already spoken for.

I’m a south east exposure. I really would like to shift some production to the afternoon with a more direct south or south west exposure, but the quote for rotating the house was too high...


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## Woodsplitter67 (Mar 15, 2021)

Production was off the hook today for march.. Today's production was 78kw with almost 12kw peak production at noon.. so far this month I'm already over 900kw.. man does this make me happy.. production was terrible the past 2 months and 2020 was 1.5kw less than 2019 production.. so I like it so far


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## stoveliker (Mar 15, 2021)

I made 27 kWh today, of a 7.2 kW system. Indeed quite large for March. I think my maximum from some summer (2 summers only) is 35.xx kWh. March so far is indeed great because there have been only 1 or 2 days that are somewhat cloudy here.


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## Solarguy3500 (Mar 15, 2021)

NoGoodAtScreenNames said:


> Yes. I have an 11kw max rated output with a single 10kw capacity Solar Edge inverter. I think the clipping / under sizing the inverter is fairly common since you rarely hit the peak potential output. I’ll let other more knowledgeable folks chime in on whether that’s good or bad. It was common in all the quotes I received so I never questioned it at the time. When picking the inverter he said the only drawback was that it wouldn’t allow adding new panels down the road. That wasn’t a concern since it’s already an above average array size and the roof is already spoken for.
> 
> I’m a south east exposure. I really would like to shift some production to the afternoon with a more direct south or south west exposure, but the quote for rotating the house was too high...



Yes, it is very common to oversize the DC to AC (rating of panels to inverter size) and there are a few reasons for that.

First, as you correctly mentioned, the amount of time that the panels will actually run at their maximum output is very small compared to the rest of the year when they they run at a lower wattage, such as cloudy days, rain, snow, etc. The DC rating of a panel is referring to something called STC or Standard Test Condition, which is a very specific set of parameters that are not often met in real world conditions. Irradiance of 1000 watts per meter square, 25°C cell temp, 1.5 air mass, etc. 

So, it's generally worth it to lose a little bit of peak production to clipping because you gain production from more inputs on the less than perfect solar days. For example, if I design 2 solar arrays for 2 different customers both using a 10 kW inverter, but one has a 10 kW DC rating so it doesn't clip, and the other has a 12 kW DC rating, the 12 kW system is going to produce more over a year than the 10 kW DC system, even though the 10 kW inverter will never output more than 10 kW AC.

@NoGoodAtScreenNames I noticed that you are in MA, and one of the main reasons why installers here don't usually use anything bigger than a 10 kW inverter is because of the net metering policy and cap system which has an exemption for systems that are 10 kW or less AC rating. By not going over 10 kW AC, you don't have to apply to the state for net metering cap space (which is full in some utilities territories) and you get the full retail value (almost) for any net metering credits you generate. One other thing I wanted to mention regarding what your installer told you about your 11 kW array being the max that can go on the SE 10 kW inverter. That's not actually correct. Depending on how long ago you got your system, the older A series SE10000 inverters had a max DC input rating of 13.5 kW DC, while the newer HD Wave SE10000 inverters have a max DC input of 15.5 kW, so you might be able to add a few panels in the future if you really needed to.


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## begreen (Mar 15, 2021)

Just 16.4kw generated today with our 5kw array pair. Shading is still an issue until April so our curve looks like a diseased camel's hump. But we're getting there. Our 2 channel inverter clips at 4500w.


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## woodhtr (Mar 17, 2021)

You guys sound like you're doing pretty good with your solar. I can imagine that in MA you probably get a lot better production in the summer with the higher sun angles.

I'm at 38 degrees latitude in CA. Unfortunately I have a lot of tree shading. I have an 8 kW array on a 6 kW inverter. This makes between 25 and 40 kWh of electricity daily, sometimes as low as 6 on cloudy days. Never have to deal with snow, but during fire season the panels can get covered in ash.


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## begreen (Mar 17, 2021)

woodhtr said:


> You guys sound like you're doing pretty good with your solar. I can imagine that in MA you probably get a lot better production in the summer with the higher sun angles.
> 
> I'm at 38 degrees latitude in CA. Unfortunately I have a lot of tree shading. I have an 8 kW array on a 6 kW inverter. This makes between 25 and 40 kWh of electricity daily, sometimes as low as 6 on cloudy days. Never have to deal with snow, but during fire season the panels can get covered in ash.


Yes, 48ºN here.  High latitude and tree shading are messing with production right now. But it changes quickly this month. By summer we have daylight until 9 and twilight until 10pm, so we do gain a lot more starting next month. Still, even though it is still light out, the sun is too off-axis to make a difference after 6pm.

This is a typical July curve. Peak is 4.2kw on this day. The system clips at 4.5 though it's rated at 4200w.


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## stoveliker (Mar 17, 2021)

In a bit of a valley here, with 7.2 kW system facing half East, half West.
In summer my max (last two summers only) has been 37 kWh per day.


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## Woodsplitter67 (Mar 30, 2021)

I went over 80kw in production for the first time this year.. did this yesterday.. Im on my way to producing 1700 kw this month or more


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## stoveliker (Mar 30, 2021)

Woodsplitter67 said:


> I went over 80kw in production for the first time this year.. did this yesterday.. Im on my way to producing 1700 kw this month or more
> 
> 
> 
> ...



Holy moly - March is a good month here indeed too, but my best month ever (since Oct. '18) was May last year (beating out the summer months) at 889 kWh.  Half yours. My best day sometime in a summer was 37 kWh.
I'm beating the previous two March's too, likely at 630 kWh or so(with the previous record for March at 584) kWh.

February was dismal, worst month ever, with 153 kWh... What is the size of your system? Mine is 7.2 kW


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## Woodsplitter67 (Mar 30, 2021)

stoveliker said:


> Holy moly - March is a good month here indeed too, but my best month ever (since Oct. '18) was May last year (beating out the summer months) at 889 kWh.  Half yours. My best day sometime in a summer was 37 kWh.
> I'm beating the previous two March's too, likely at 630 kWh or so(with the previous record for March at 584) kWh.
> 
> February was dismal, worst month ever, with 153 kWh... What is the size of your system? Mine is 7.2 kW



my best month is june/July with over 2400 kw in production per month. my system produced about 18/19kw per year.
this winter was not so great... this month is off the hook so I'm making up some ground.. I use alot.. my hot tub is like 600 gallon.. my HW is electric and I run a greenhouse..I have 3 refrigerators and a stand up freezer and a 15 year old daughter that can drain my 80 gallon hot water heater if you don't tell her to hurry up...


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## stoveliker (Mar 30, 2021)

Woodsplitter67 said:


> my best month is june/July with over 2400 kw in production per month. my system produced about 18/19kw per year.
> this winter was not so great... this month is off the hook so I'm making up some ground.. I use alot.. my hot tub is like 600 gallon.. my HW is electric and I run a greenhouse..I have 3 refrigerators and a stand up freezer and a 15 year old daughter that can drain my 80 gallon hot water heater if you don't tell her to hurry up...



Lol. I fear for 5 years from now when my daughter is 15 ( and son 13)..


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## Woodsplitter67 (Mar 30, 2021)

stoveliker said:


> Lol. I fear for 5 years from now when my daughter is 15 ( and son 13)..



My son is 13.. no worries on him and over use.. most days he's in and.out In 10 to 15 minutes.. 
solar was one of the best decisions iv made..


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## begreen (Mar 30, 2021)

We're right about even now with production vs consumption at 25kw day. There is still some afternoon shading for an hour or so that should get better soon as the sun gets higher in the sky.


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