BMW i4 Reservation Tracker: Add Yours Here!

Has anyone considered or installed Solar Roof to charge their EV?

9174 Views 130 Replies 28 Participants Last post by Elle BMW, 3 d ago

Flyingman

Discussion Starter · Apr 6, 2022

I have been researching a lot about Solar PV (rooftop) and actually reviewed some 15 or so offers from many suppliers. I have locked in on one company and expect to install a 15kw system over next few months. Idea is to be Net Zero and I just revised the sizing to include an EV. I used the i4 as my EV and assumed about 10-12k miles/yr at about 36kwh/100 miles. I think that gave me about 330kwh/month to recharge the car at home, which is where I expect 90% of the time it will be charged.

I've got two nearby neighbors that have Teslas (one actually has 3!) and they also have Solar Roofs, so I assume they are doing very similar to what I am planning.

Has anyone else actually done this exercise and if so how did you estimate and calculate the amount of Solar PV you would need?

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Elle BMW

· #81 · 1 mo ago

Installers are coming April 24th. Can't wait.

Reactions: 2

stryker

· #82 · 1 mo ago

Elle BMW said:
Installers are coming April 24th. Can't wait.

How much is the cost all in?

Elle BMW

· #83 · 1 mo ago

stryker said:
How much is the cost all in?

I think about 32K for an 8.2kw system. No idea if that is a good price or not, lol.

stryker

· #84 · 1 mo ago

Elle BMW said:
I think about 32K for an 8.2kw system. No idea if that is a good price or not, lol.

thanks but I thought you were talking about this

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Markus E

· #85 · 1 mo ago

Flyingman said:
I have been researching a lot about Solar PV (rooftop) and actually reviewed some 15 or so offers from many suppliers. I have locked in on one company and expect to install a 15kw system over next few months. Idea is to be Net Zero and I just revised the sizing to include an EV. I used the i4 as my EV and assumed about 10-12k miles/yr at about 36kwh/100 miles. I think that gave me about 330kwh/month to recharge the car at home, which is where I expect 90% of the time it will be charged.

I've got two nearby neighbors that have Teslas (one actually has 3!) and they also have Solar Roofs, so I assume they are doing very similar to what I am planning.

Has anyone else actually done this exercise and if so how did you estimate and calculate the amount of Solar PV you would need?

I did exactly what you suggested. In 2016 we received our BMW i3 and got solar panels. You need to know the annual consumption of you house and estimate the car consumption based on your annual mileage and the rated consumption rate of your car. This resulted in 24x 300W solar panels. In 2018 we got a second EV and added 12x panels. Now we are almost net zero with two EV‘s.

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JToddK

· #86 · 1 mo ago

Elle BMW said:
I think about 32K for an 8.2kw system. No idea if that is a good price or not, lol.

Kind of depends on the installation difficulty, equipment selected and the local labor rate. Typical 2023 estimates I see are $2.75-$3.25 per watt. You're close to $4/watt; could be some of the things I listed. The rising cost of purchased power and the declining W/$ cost of panels is moving me closer to doing a 6kW array. (That's all I can fit within the location and aesthetic constraints.) Tax credits (currently 30%) decline in a couple of years, so maybe, for me, it's time to do it.

Reactions: 1

Flyingman

Discussion Starter · #87 · 1 mo ago

I can update you on my actual situation today. I installed 15kw with 34 X 440w Panels. I went live in Nov 2022 and now in April 2023 I have about a 600kwh surplus to the grid (i.e. they owe me!). I've done 95% of charges at home but drive less than the calculated 1,000-1,200 miles/month. I've lowered my home AC Temp a few degrees (to please momma!) and I keep my pool heater on all winter (previously unheard of!). My cost all in was $28,000 after tax incentive so about $1.86/watt DC. I recall they quoted my $1.70 but there were a few additional costs related to the interconnection with utility, I had to change the cable run from Transformer. Bottomline I am saving about $400/month on my Electric Bill and Gas bill for my one EV. I've ordered a second EC (i4e35 for Momma!). And our Utility rates have increased twice since then, so actual saving is more now.

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rollermonkey

· #88 · 1 mo ago

Wow. That is a lot of production for one winter. Then again, your post-credit cost is more than my pre-credit cost. That’s more than double my installation’s benchplate rating. (14.96 vs 7.29) I see why they said it was cheaper to install more up front than add more later.
what sunny clime is this in?

Flyingman

Discussion Starter · #89 · 1 mo ago

rollermonkey said:
Wow. That is a lot of production for one winter. Then again, your post-credit cost is more than my pre-credit cost. That’s more than double my installation’s benchplate rating. (14.96 vs 7.29) I see why they said it was cheaper to install more up front than add more later.
what sunny clime is this in?

Sunny South Florida. When it isnt raining!

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Flyingman

Discussion Starter · #90 · 1 mo ago

Flyingman said:
Sunny South Florida. When it isnt raining!

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Flyingman

Discussion Starter · #91 · 1 mo ago

Elle BMW said:
I think about 32K for an 8.2kw system. No idea if that is a good price or not, lol.

That must be pre-tax and is a bit high. I paid $1.7/w DC, recall you install DC but produce really in AC, about 80% of the DC rating.

So 8.2kw DC will give about 6.56kw AC (Capacity), and then you may get about 20% of your installed capacity year long, so 6.56kw ac X 24 hours/day X 0.2 (20%) X 365 day/year = 11,500 kwh/year. If you look at your average monthly bill and multiply by 12 months, get your annual average. Goal is to be close to Net Zero, maybe a little over 5% or so. Most utility companies will not approve more than 5-10% over your annual consumption.

And of course these number will vary from region to region (depending on sun angle, weather, etc...) and your own roof angle, orientation, shading from trees, neighbors, etc...

There are some good websites that will give you a basic estimate, fairly accurate, but many are linked to websites that will want to share your contact with the door knockers and phone ringers, so beware! They will pester you relentlessly.

Reactions: 1

rollermonkey

· #92 · 1 mo ago

Figured out what the app was reporting for the panels. The day’s running total production for each panel at that moment.
Oops.
Clearly a violation of the 10% Rule.

Reactions: 1

x43x

· #93 · 1 mo ago

Our solar panels where finally turned on yesterday. It's been overcast and raining, but we still managed to produce over 20kWh in a day and half. Can't wait for a proper sunny day mid week. Originally we were going to produce 110% of our yearly consumption, but we now have two EVs, so it may be lower if we have to charge a bunch.

Reactions: 2

rollermonkey

· #94 · 1 mo ago

x43x said:
Our solar panels where finally turned on yesterday. It's been overcast and raining, but we still managed to produce over 20kWh in a day and half. Can't wait for a proper sunny day mid week. Originally we were going to produce 110% of our yearly consumption, but we now have two EVs, so it may be lower if we have to charge a bunch.

I started using the 2-year EA promo while I wait for sunnier days.

Flyingman

Discussion Starter · #95 · 1 mo ago

rollermonkey said:
Figured out what the app was reporting for the panels. The day’s running total production for each panel at that moment.
Oops.
Clearly a violation of the 10% Rule.

The 10% (actually it is 115%) rule is the annual average production, not anything instantaneous or hourly, daily, etc.... There was an article about some Florida guy that installed a massive solar panel system for a home and FP&L refused to connect him because he was producing way more. He sued them. Never heard what the outcome of that was. I'll find and post article here.

Flyingman

Discussion Starter · #96 · 1 mo ago

pv-magazine-usa.com

Florida man takes FPL to court, alleging the utility acts like a net metering regulator

Achim Ginsberg-Klemmt has filed an appeal against the denial of a petition to improve the net-metering regulations in Florida. He alleges the company's 115% generation policy, requirement of insurance on larger residential projects and "As-Available-Energy” rates disincentivizes large...

pv-magazine-usa.com

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Elle BMW

· #97 · 1 mo ago

My installers are here right now, this is exciting. can't wait to see the software and see what I'm producing!

Reactions: 2

x43x

· #98 · 1 mo ago

Elle BMW said:
My installers are here right now, this is exciting. can't wait to see the software and see what I'm producing!

I was really excited when our installers came too. They didn't get turned on for three more months though! Hopefully yours goes faster. Are you getting an Enphase system?

Elle BMW

· #99 · 1 mo ago

x43x said:
I was really excited when our installers came too. They didn't get turned on for three more months though! Hopefully yours goes faster. Are you getting an Enphase system?

OMG it better get turned on like tomorrow!!

x43x

· #100 · 1 mo ago

Not sure what it's like where you live, but in WA, I had to wait for L&I to come out and inspect the installation, then our utility provider came out for final testing before the switch was pushed. Not helping the situation was the installers not taking proper photos the first time and dropping the ball for over a month before coming back out to finish the job. It was a couple weeks between L&I and Puget Sound Energy. You also might need to get a Net Meter installed by your provider if going that route. The day after the button was pushed, I got an email from Enphase and got the app setup. It's pretty nice since I can see output from each panel and it has info on all the inverters and gateway, not to mention several different ways to see your production.

Reactions: 1

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