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I figure my Bolt is using about 50 kWh a week to go 190 miles, or about 2,600 kWh a year. That's about 20% of my actual measured production (1.22 MWh a year actual production, from twenty-two 335 watt panels). I have a really nice east southeast exposure, at 22 degrees roof slope. The whole system cost me about $27k after tax credits and rebates. Estimated payback is about eight years.

You definitely use a lot more energy than me. Let your installer do the math. They are the experts, not us.
 

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Discussion Starter #82
The math is very simple to do. I know the pitch of the roof, the exact azimuth of the roof, and the hardware information. I would definitely install the system myself if it wasn't two stories up and all loopholes you need to jump through to get it installed. Getting permits, getting permission for PG&E to switch on, and having licensed people do work is what we have to do with all the regulations in our state.

PVWatts is an amazing website that takes local data, the array size, array orientation, slop of array, and other information to estimate how many kWh you system will produce in your area. Not only that, but it allows you to simulate hour by hour for the production. You can than take that data into a spreadsheet and put your different facing arrays together. It is a great tool and what many installers use. Many installers won't do what is 100% in your best efforts. They will do what is easiest for them. If they could, I believe they would put all my panels on my East roof since it is the simplest installation. Many of the people I talked to weren't even familiar with the EV-A plan and the TOU rates with the plan. I do the math because I have a Masters in Physics and it is very simple. I always question people, even if they are regarded as "experts". There were "experts" trying to sell me a Bolt and told me I needed oil changes.
 

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Another data point: I've got 5kW on a pitched roof that faces South in So. CA. (HB). No shadows...pretty much an ideal install. My yearly production is 8.4MWHr. I'm on regular old tiered residential, and my avoided cost is all in Tier 2. We stuck with residential because we're retired and want to be able to consume electricity during the day, and charge at will. (We were on TOU when we worked for a living.) Payback for the system will be in nine years. It sounds like a long time, but when you consider the effective ROI of ~10%, I'd rather have my investment on the roof at 10% than a bank CD at 1.5%!
 

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Discussion Starter #84
Installation date for my solar is in two weeks. The added EV charger to the SolarEdge inverter is not available yet, they will be adding it in after the fact. They will do this at no cost for me, so hopefully I will be charging my Bolt directly from my solar panels my May!


My roof hindered my plans for putting the panels where I want them. I only can fit 4 panels on the West roof, 10 on the South, and the remaining 16 will be on the East. I will be clipping more than I calculated because of this, but the amount of energy I will lose is not even close to the money I would have to spend modifying my panel. Plus as degradation happens, the clipping will be a non-issue in the next 10 years.
I was looking for a CPO Model S, but the prices have sky rocketed on them. You could always find them for under $40,000, but now the cheapest is $50,000. The CPO Tesla's are way overpriced right now compared to the price of a new Model S. By the way, here is my energy usage last month!
Peak 157 kWh @$0.32
Part-Peak 161 kWh @$0.20
Off-Peak 1,079 kWh @$0.12
Total electric charge for this month is $219. I was spending about $200 in gas a month driving my Ford Fusion Hybrid. The EV-A plan is awesome for people who put a lot of mileage on their EV's!


 

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Don't sweat clipping.... it's not a bad thing... it's not like too many panels will hurt a grid tie inverter (if you stay within the string voltage limits). Having clipping means that your system will generate more power earlier in the day for longer and generate more power on cloudy days. Think of it as putting D cells in your boom box instead of C cells...

 

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Discussion Starter #86
I have seen these graphs before, but I don't know what type of solar system they represent. Is that an older string inverter, micro-inverter, or power optimizer system? With the different technologies I don't think that the power curves of the three available types of systems would all have this type of output. I could be wrong though...
 

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Don't want to get too bogged down in PV stuff in a car forum.... String inverters are dirt simple with all panels in series like batteries. If you shade ONE panel, you kill the whole string. Most string inverters have two or three inputs, so shade one panel you lose 1/3 or 1/2 of your production. Microinverter systems and SolarEdge systems with optimizers can "route around" a shaded panel and you'll only lose the power that one panel would have made. Aside from that I can't think of a reason for a different performance curve for the different types of systems. Without getting too bogged down it's customary to over size the array by 25% over inverter capacity. Really helps on cloudy days. YMMV.... and I ain't no expert.... :)

4 panels on your west roof is a shame... only 1kw and 160v... many string inverters won't start producing at all until 125V on the input. Hope you are getting a micro inverter or solar edge system. 30 panels is a nice respectable system though! wooo!
 

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Discussion Starter #88
I don't think any solar companies deal with string inverters anymore. I am getting the SolarEdge system. I am also getting 375 Watt panels. My system is 148% of the inverter. The new SolarEdge inverters all go up to 155%. To get a 10 kW inverter I would have to spend a few thousand modifying my panel, so whatever energy I lose will come nowhere near what I would have to spend.
 

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Discussion Starter #89
Update on my solar adventure. The installation date last week was the exact date I bought my Bolt last year, found that kind of funny. They were able to squeeze one extra panel on the South side so it is 15 East, 11 South, and 4 West. I can't put up any additional panels unless I go the North side. I am glad I choose the 375 Watt panels.


I can't monitor or feed to the grid until PG&E comes out. Estimated time is 1 to 2 weeks. I am clipping much more than what I expected, but I am not complaining about it. I was putting out 7.6 kW for about 5 hours today, which means I would have lost out on a lot of kWh if I was hooked up to the grid. I can't wait until I can start monitoring my use and also when the EV charger becomes available for the inverter.
 

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Don't trust the installers

Many installers won't do what is 100% in your best efforts. They will do what is easiest for them. If they could, I believe they would put all my panels on my East roof since it is the simplest installation. Many of the people I talked to weren't even familiar with the EV-A plan and the TOU rates with the plan. .......There were "experts" trying to sell me a Bolt and told me I needed oil changes.
I would like to endorse these comments. My advice is, if you don't have a masters in physics, that you obtain an independent evaluation of your site, with recommendations for panel installation etc. Then talk to the contractors, who I would say never have a masters in physics, obtain their estimates; then you are armed to judge who is honest, while still remaining in the dark about who is incompetent.
 

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Watch the snow

Don't want to get too bogged down in PV stuff in a car forum.... String inverters are dirt simple with all panels in series like batteries. If you shade ONE panel, you kill the whole string. Most string inverters have two or three inputs, so shade one panel you lose 1/3 or 1/2 of your production. Microinverter systems and SolarEdge systems with optimizers can "route around" a shaded panel and you'll only lose the power that one panel would have made.
Right. I have microinverters, and its a boon in the snow. As the snow clears off the panels you can see each panel coming back online separately. Indeed, I don't need to look on my roof anymore to see how much snow has retreated. Its right there in the software. Geez, another reason to stay on the sofa...
 

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Sorta off topic, but wanted to let someone know. We crossed the 100 megawatt hour of solar production yesterday, since our original install March 2010. Theoretically enough to drive our Bolt about 400,000 miles.
 

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Discussion Starter #94
So far for my true-up bill for 4 months, I have used 356 kWh more than I gave PG&E. Because of TOU, I have $180 in credits!!! Solar for me is the best investment I have made.

Since March last year, which is about 17 months, I have produced 28.63 MWh.
 

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PVOutput.org is the best site for pv real life data. Look around your location for systems to see what they produce. There is years of historical data so you can do pretty accurate estimates. Buying my Bolts to feed off the surplus my 14.5kwh system produces made a lot of sense for me.

here is my system - https://pvoutput.org/list.jsp?userid=74220
 

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So far for my true-up bill for 4 months, I have used 356 kWh more than I gave PG&E. Because of TOU, I have $180 in credits!!! Solar for me is the best investment I have made.

Since March last year, which is about 17 months, I have produced 28.63 MWh.
Well, if you are in an area where PG&E is turning off power, now is the time to look at adding PowerWalls and be able to be grid independent, as needed.
 

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I wish WE Energies in Wisconsin would support Solar, they have done just about everything they can to block it. We still have TOU but they just recently killed the Natural Gas prepay program that I really enjoyed, they killed the air conditioning control program and have raised fee's for solar frequently. We have no EVSE incentives from the state or our utility.
 

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In California, cities have been taking utility back from PG&E (the company that tells you chromium is good for you) and running their own power system. With advances in tech, micro-grids and vehicle to grid are the future. Private utilities have too much baggage and vested interest.

Arizona has been very hostile to Solar.

Nevada had votes to kill the state monopoly for Nevada Energy and the casinos are eagerly waiting for that day so they can get cheap power from solar+battery.
Fortunately, though, NVE has been lowering rates (rates today is lower than 2012) to maintain the peace/sustain their profit gravy train. :)
 
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