First Month Owner Experience Charging with Solar Panels

[scottintucson]

My utility limits estimated production to 115% of past billings. The rules have changed over the years for new installations, but they have tended to honor commitments made at installation. This thread has surprised me by the differences in how solar is treated by the individual utilities. It seems my utility (Tucson Electric Power) is relatively friendly.

Don't forget pool pumps...

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[HuntingPudel]

Huh, I guess I need to look into a VPP program here. It could help pay for at least part of a battery system.

 

[Reign of Ravens]

This year, we had 7 events that my Powerwalls contributed to and as of now I’ll be getting a check for about $422 from Tesla for my contribution to the grid. I rarely pull power from the grid except maybe after several cloudy days in the winter when the Powerwalls don’t have enough solar to charge back up fully. I usually run a negative balance with PG&E and now will get paid by Tesla for my contribution. What I’m trying to say is, I think you will like being on the Virtual Power Plant program.

I've been watching it more closely and it seems like every evening and every morning at least a small amount of the battery goes back to the grid. I don't mind - that's where the real money is. Otherwise the strategy is interesting, we're definitely drawing more from the grid and for much of the morning the solar panels seem to prioritize the grid over the batteries. Even by the afternoon, maybe 4 kW will be going to the batteries, and the rest goes to the grid or the house. But as the afternoon drags on, potentially all of the solar production goes to the batteries if they're not sufficiently charged, and the grid will power the house. In the evenings, the amount drawn from the batteries for the house also seems to be capped, and above a certain rate it'll draw from the grid.

Despite that, it seems like we're about net even with giving back to the grid the same amount that we take. It also means that the batteries are below 90% for longer amounts of time and are at a higher state of charge in the morning, which is theoretically beneficial for battery life longevity (not that Tesla has ever advised on the ideal state of charge for long periods of time for Powerwalls) and for maintaining more charge for a massive outage. It seems to be prioritizing the batteries for the grid, but not exclusively.

We used to have 100% energy independence before the majority of time, but it seems like most days we're in the 70-80's% for energy independence. We'll see - if we come out ahead then I don't mind. Our base bill even with 100% energy independence was around $25, so even if it just ends up being totally free, I'd be thrilled.

Sizing Solar for house will depend on MANY factors:
- location, orientation, tilt, sun exposure will determine kWhr produced / kW Solar

Just one fun anecdote... our solar panel company did the analysis and chose to install our first array on two facets of our house, calculated as giving the highest yields. When we expanded our system we added the generation 4 panels, but there were fewer of them compared with the first array. I figured that fewer panels and suboptimal roof placement would mean a lot less power, but more stable throughout the year... well, that second array outproduces the first array. Gen4 isn't hugely more efficient compared with gen3 panels, so I don't think that's it entirely. It makes me wonder if the company had the optimal placement incorrect.

 

[Just Lurking]

I got my 12 kw solar with battery completed just after Thanksgiving but with winter in the North I need to wait until warm weather returns before it produces anything decent.

Would be curious to know what kind of generation you are averaging during the dreary winter months? I'm also in the PNW and am considering going solar within the next year or two.

 

[dtbaker61]

Would be curious to know what kind of generation you are averaging during the dreary winter months? I'm also in the PNW and am considering going solar within the next year or two.

winter production for *most* installs in areas that have 'winter' can be as low as 1/2 what summer production is because of the angle of sun and hours of daylight. totally depends on local weather patterns and UV intensity. The beauty of grid-tied solar is you get paid for summer surplus, take from the grid when needed in the winter, and do not HAVE to buy batteries.

 

[Just Lurking]

winter production for *most* installs in areas that have 'winter' can be as low as 1/2 what summer production is because of the angle of sun and hours of daylight. totally depends on local weather patterns and UV intensity. The beauty of grid-tied solar is you get paid for summer surplus, take from the grid when needed in the winter, and do not HAVE to buy batteries.

Grid tied solar is great, and that's what we'll do, but I'm also interested in battery storage and V2H as we're in an area vulnerable to power outages. I'm hopeful the Mach-E receives a software update to add support for V2H like the Lightning.

It's extremely cloudy and rainy in the winter in my neck of the woods, so I'm thinking solar production is going to be less than half. Curious as to how much less, though, and whether it would be sufficient to maintain critical loads in the winter.

In the meantime, I've been reading a lot of your threads about how to cut holes for access to the battery connectors in order to run an inverter. I'm not super handy, but you and the others who have done it have made it seem easy enough that I MIGHT give it a shot. I'd really rather pay someone else to do it, though!

 

[dtbaker61]

Grid tied solar is great, and that's what we'll do, but I'm also interested in battery storage and V2H ...

It's extremely cloudy and rainy in the winter in my neck of the woods, ... whether it would be sufficient to maintain critical loads in the winter.

You first need to determine what your average daily 'important loads' are, and how much Energy you'd use per 24 hrs. I'd suggest you get a self-install-able monitoring system, something like the Emporia VUE' system, and get a good idea what circuits you consider important.

Then, you can contact local Solar Installers to size your home up for annual offset, and they should be able to show you what the system proposed will generate month by month, or you can verify with a free estimator like https://pvwatts.nrel.gov/ in case you want to adjust the size of the system to be sure you've got critical loads covered mid-winter.

In the meantime, I've been reading a lot of your threads about how to cut holes for access to the battery connectors in order to run an inverter. I'm not super handy, but you and the others who have done it have made it seem easy enough that I MIGHT give it a shot. I'd really rather pay someone else to do it, though!

10 minutes with a 1-7/8" hole saw is all you (or a trusted friend) really need.... I would highly suggest access to the 12v +/-, and HV emergency disconnect.

 

[nmope]

Thank you for this thread! For those with systems already working what date did you use for claiming the tax credit? Date of install? Date paid? Date permission to operate?
Any difficulty getting credits?
My system has been installed earlier this month and is generating but i have not gotten Permission To Operate yet (7.6KW+1PW). So far I have been using same a similar charging routine as @scottintucson but I am definitely not able to fully to completely cover my MME requirements with just solar and I have to supplement with grid charging (averaging about 1100 miles/month with what seems to be about 2.6kW/mile)

 

[dtbaker61]

Thank you for this thread! For those with systems already working what date did you use for claiming the tax credit? Date of install? Date paid? Date permission to operate?
Any difficulty getting credits?

Federal tax credit is supposed to be claimed the tax year the system becomes operational. That being said, the Federal form only cares about the the Gross amount paid, and that the system actually was installed as the credit (30%) is the same for TY2022 and TY2023. No supporting docs are required as to when system was Operational versus Installed; so, for people installed at the end of the year, but perhaps waiting for final inspections, it is not uncommon to claim in the year Installed rather than wait.... not 100% correct, but not uncommon.

My system has been installed earlier this month and is generating but i have not gotten Permission To Operate yet (7.6KW+1PW). So far I have been using same a similar charging routine as @scottintucson but I am definitely not able to fully to completely cover my MME requirements with just solar and I have to supplement with grid charging (averaging about 1100 miles/month with what seems to be about 2.6kW/mile)

1100 miles /mo consumes more this time of year.... If your actual trip is showing average of 2.6 miles/kwhr, it will likely rise to 3.0 miles/kWhr or more in the summer temps.... combined with longer days and better sun angle producing almost twice as much from Solar, you may find you are covering 100% come spring.

 

[Just Lurking]

You first need to determine what your average daily 'important loads' are, and how much Energy you'd use per 24 hrs. I'd suggest you get a self-install-able monitoring system, something like the Emporia VUE' system, and get a good idea what circuits you consider important.

Then, you can contact local Solar Installers to size your home up for annual offset, and they should be able to show you what the system proposed will generate month by month, or you can verify with a free estimator like https://pvwatts.nrel.gov/ in case you want to adjust the size of the system to be sure you've got critical loads covered mid-winter.


10 minutes with a 1-7/8" hole saw is all you (or a trusted friend) really need.... I would highly suggest access to the 12v +/-, and HV emergency disconnect.

Thanks! Part of my challenge is my home runs on propane right now, but we are going to electrify everything (heat pump, electric water heater, induction stove) over the next couple of years. We also probably need to upgrade our load center (circuit breaker panel) as it only ha 20 slots and is full. We could free up some slots by switching to double pole breakers, but probably not enough to electrify everything.

So I don't have a good sense on energy needs beyond some very rough back-of-the-envelope estimates right now.

 

[markboris]

Would be curious to know what kind of generation you are averaging during the dreary winter months? I'm also in the PNW and am considering going solar within the next year or two.

I'm in NorCal at the foothills of the Sierra Nevada mountains. We get about 6 months with days of mostly full sun and the other 6 months about half the time with full sun. Then there are the days, like we have had the last few weeks, of dark clouds and rain/snow. My production can vary quite a bit as all homes with solar can.

Typical summer day (full sun) close to summer solstice:

Typical winter day (full sun) close to winter solstice:

Typical winter day cloudy, rain/snow:

 

[Just Lurking]

I'm in NorCal at the foothills of the Sierra Nevada mountains. We get about 6 months with days of mostly full sun and the other 6 months about half the time with full sun. Then there are the days, like we have had the last few weeks, of dark clouds and rain/snow. My production can vary quite a bit as all homes with solar can.

Thanks for those examples! Pretty amazing how much solar power decreases on a rainy / cloudy / snowy day. That's great information to know that it can be less than 10% of the power generated on a sunny day.

 

[dtbaker61]

Thanks! Part of my challenge is my home runs on propane right now, but we are going to electrify everything (heat pump, electric water heater, induction stove) over the next couple of years. We also probably need to upgrade our load center (circuit breaker panel) as it only ha 20 slots and is full. We could free up some slots by switching to double pole breakers, but probably not enough to electrify everything.

So I don't have a good sense on energy needs beyond some very rough back-of-the-envelope estimates right now.

switching from propane to heat pumps (air-to-water exchangers and air-to-air minisplits) is pretty common in my area. I find that a formula estimated 3 kWhr/ft2/yr per heating season and 1 kWhr/ft2/cooling season works on just about right for a 'regular' stick-built house with normal amounts of insulation, decent windows and doors, and average passive north/south heat gain/loss.

Your total load will be = 'baseload electrical appliances' + EV charging + heat/cooling load

so, if your weather is way different than Santa Fe, NM.... adjust the numbers a little....

 

[Kaddabriol]

Thanks for sharing your insightful experience with us! It's fascinating to hear about your journey as a new owner of the 2022 Mach E. Your focus on leveraging solar power for charging is not only environmentally friendly but also financially savvy. It's commendable how you've tailored your charging routine to coincide with peak solar production hours, ensuring maximum efficiency and cost-effectiveness.
If you're looking for more insights or products to enhance your solar charging setup, you might find useful information on solar panels cork. Good luck!

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