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Got a design. Any thoughts before I accept?
- Thread starter Grayson73
- Start date
Matt-FL
Member
Couple of notes:
First, if you are in an HOA, make sure there is no verbiage about panels being visible from the street. That may alter your design. Florida has a state law that forbids HOAs from this, but they still fight it. I don't know about Maryland.
If you can afford it, I'd suggest a third powerwall. Don't believe the '7+ days of backup', as that is in no way true. I have four and a 2000sf house, and mine runs down at night in the summer down to 30%. Winter is generally a little better, but less sun to fill, still below 50%. 7+ days perhaps takes into account a sun refill during the day. Also, if you end up with PW2 or PW+, you're limited to 10kW for running your water heater, AC, etc. Having a third increases that to 15kW. Even with 4, there are times I hit 16kW when the AC is running, water heater kicks on, dryer comes on, etc. If you have an EV, you can drain two powerwalls in 2.5 hours.
It does look like you could fit a few more panels on certain roof lines, I'd suggest maxing out now versus later.
Oh, and make sure they are installing (2) 7.8kW inverters.
Looks great! Will be a nice system!
First, if you are in an HOA, make sure there is no verbiage about panels being visible from the street. That may alter your design. Florida has a state law that forbids HOAs from this, but they still fight it. I don't know about Maryland.
If you can afford it, I'd suggest a third powerwall. Don't believe the '7+ days of backup', as that is in no way true. I have four and a 2000sf house, and mine runs down at night in the summer down to 30%. Winter is generally a little better, but less sun to fill, still below 50%. 7+ days perhaps takes into account a sun refill during the day. Also, if you end up with PW2 or PW+, you're limited to 10kW for running your water heater, AC, etc. Having a third increases that to 15kW. Even with 4, there are times I hit 16kW when the AC is running, water heater kicks on, dryer comes on, etc. If you have an EV, you can drain two powerwalls in 2.5 hours.
It does look like you could fit a few more panels on certain roof lines, I'd suggest maxing out now versus later.
Oh, and make sure they are installing (2) 7.8kW inverters.
Looks great! Will be a nice system!
Matt-FL
Member
Lucky you! I have one, and they told me I was fine to put up solar panels as long as you couldn't see them from the street. The front of my house faces north, so I wasn't planning on putting any there anyways.
I did reply back informing them of the Florida state law statute, explaining that they couldn't stop anyone from doing that, and to please not spend our neighborhood money on trying to block any neighbors from doing it since it would be a waste of funds. No response back, but hopefully they at least read it.
I did reply back informing them of the Florida state law statute, explaining that they couldn't stop anyone from doing that, and to please not spend our neighborhood money on trying to block any neighbors from doing it since it would be a waste of funds. No response back, but hopefully they at least read it.
charlesj
Active Member
Yep, some HOAs are crazy what they think they can get away with. Read one horror story just a day or so ago, in MO, I think.
I agree with the more panels, I always recommend adding more vs the vendor/installer recommendation.
They are trying to hit a price point that will make you jump, but the additional cost of a few panels today is far less than in a year (if you can even get Tesla to add them).
We went with 3x Powerwalls, and they mostly cover our daily/overnight usage, except in the heat of summer. If I could have justified the $ for 4, I would have done it, and I still have thoughts to add 1 or 2 later...
Looks like these are about 400watt panels, and if you can go with 2x 7.8KW inverters (or powerwall+), I would recommend getting to about 17KW of panels, or ~9 more panels than you currently have speced (42 total). If you can't get that many, still add more than the 33, even 1 or 2 more would help. You may run into issues with the utility, as Tesla is saying that will already hit 129% of your electric usage (yearly basis).
We had artificially low usage due to not driving much (early covid), and had to go with 50 370watt panels, but we went 2x 10KW inverters, and 18.5KW of panels, and then a bit over a year later, added another 12 440watt panels, to make about 23KW DC, on the 20KW of inverter.
Every utility in the country is trying to move away from straight net metering, and to an offset based compensation. I pay $0.11-0.16/kwh and my utility pays me $0.086/kwh, new customers with solar and my utility are less than $0.07/kwh now.
-Harry
They are trying to hit a price point that will make you jump, but the additional cost of a few panels today is far less than in a year (if you can even get Tesla to add them).
We went with 3x Powerwalls, and they mostly cover our daily/overnight usage, except in the heat of summer. If I could have justified the $ for 4, I would have done it, and I still have thoughts to add 1 or 2 later...
Looks like these are about 400watt panels, and if you can go with 2x 7.8KW inverters (or powerwall+), I would recommend getting to about 17KW of panels, or ~9 more panels than you currently have speced (42 total). If you can't get that many, still add more than the 33, even 1 or 2 more would help. You may run into issues with the utility, as Tesla is saying that will already hit 129% of your electric usage (yearly basis).
We had artificially low usage due to not driving much (early covid), and had to go with 50 370watt panels, but we went 2x 10KW inverters, and 18.5KW of panels, and then a bit over a year later, added another 12 440watt panels, to make about 23KW DC, on the 20KW of inverter.
Every utility in the country is trying to move away from straight net metering, and to an offset based compensation. I pay $0.11-0.16/kwh and my utility pays me $0.086/kwh, new customers with solar and my utility are less than $0.07/kwh now.
-Harry
I would love to get more panels, but it seems like this is the max I could select on the Tesla website. They are projecting 129% usage because I just got my EV 2 months ago. I only used 9000 kWH last year but I project 13,000 kWh this year due to the EV, and we plan to get a second one in a few years. How do you get them to factor those in? Or maybe they already maxed it out based on my roof.
12MWh annual estimate seems a bit low a system that size, is there shading or snow involved? If you plug your system configuration into PVWatts, what estimate do you get? If I put your MD location in, I get 12MWh if it were all north facing panels, and 18MWh if it were south facing. Yours should be somewhere in between.
Sadly, yes, there is a lot of shading. A lot of tall trees from various neighbors.
We did not go through Tesla (they refused to work with our roof type, which happens to be the most common or second most common roof in Tucson, a built up roof), so I don't know the process to ask for more panels.
If your design came via Email, I would reply and ask if you can add more panels.
-Harry
I was just told "There is no room to add any panels to your roof once all fire setbacks and installation spacing requirements are accounted for.
Moreover, per the email I sent the other day, once customers accept the pricing details, no customer-requested changes can be made to the system design."
We had similar issues on our old house, we could not go past certain fire set backs, even though we had the whole other side of the roof that was not getting panels and would have the same access. We maxed out what we could, which covers about 90% of the usage.
-Harry
Matt-FL
Member
Well, at least you looked into it! If that is the max, then you know you are getting the most you can on your roof!
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