ajdelange
Well-Known Member
- First Name
- A. J.
- Joined
- Aug 1, 2019
- Threads
- 9
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- 2,883
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- Location
- Virginia/Quebec
- Vehicles
- Tesla XLR+2019, Lexus, Landcruiser, R1T
- Occupation
- EE Retired
That's what a lot of them do but there is a lot more to it than that. The direction your roof facets face, shadowing trees, the weather in your vicinity etc. But before getting into that you need to determine your requirements.I think they half-assed their assessment because they just used a satellite photo of my roof to determine how many they could fit.
You have a truck with high consumption - close to 400 Wh/mi. The average American drives about 35 mi/day. That will take 0.4*35 = 14.5 kWh out of your battery and in addition to that you will have to cover approximately 1.5% of 130 kWh = 2 kWh phantom drain per day for a total of 16.5 kWh. The average American household (no BEV) consumes 30 kWh/da. An RIT uses more than half of this.I'm looking for solutions that will also let me charge my truck
As an example of how this translated to solar panels I have 45 of them on the garage where I park the BEV and they produce 13 kW in full sun so that I need 16.5/13 = 1.3 hours of full sun (hFSE) just to maintain the R1T. In the summer I get 5 or 6 hFSE/da. In the dead of winter 2 or less. So while there is plenty of margin for other loads (lights, A/C, the Tesla...) in the summer, in the winter, there isn't.
I have some rather high power requirements
Beyond the truck you have, of course, the other loads to think about. I heat and cool the main house with heat pumps which suck a lot of electricity to the point that my average load is right around 3 times the national average at 100 kWh/day over the year. Quite by coincidence I havre 97 panels which produce 80% of that (on average - it's a net metered system independent of the panels on the BEV garage).One installer said they wanted to install 97 panels!
It's probably clear that 97 panels is not practical for most but another factor to consider is that there is probably no way to fit that many panels on south facing facets of your roof even if you are willing to foot the bill. Panels on east and west facing facets will not collect as much sun as ones on south facing surfaces but they do collect sun and are worth considering if you have high electric loads or if you want to cover more of your bill. Tesla even recommends doing this in its PowerWall installation app notes. The local installer whose website you visit will NOT consider this. They will propose a system that may cover half to 2/3 you total need if your loads are typical. If you want more you will have to hire an engineer to design a system for you (or do it yourself) and then tell the installer what you want done.
All this is to let you know that you will probably be disappointed with respect to how much of your electric bill solar can cover. But keep in mind that half of it isn't to be sneezed at!
One more note: Solar is in big demand now. You may have trouble getting the attention of any installer in your area and asking one to deviated from his cookie-cutter approach isn't likely to get him to cooperate.
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