TSLA Pilot
Active Member
I called Solar City and I thought for a moment that I was talking to Tesla
I spoke with a nice enthusiastic young gentleman who was perfectly happy to talk leasing a full house system for California. When we got to me being in Florida, wanting access the the battery back up, wanting information on the size and capability of the systems,,,, we ran out of run way. SC does not sell anything. They are still in pilot with the battery system and, from what I gathered, do not have enough batteries to sell systems even if they wanted. The person I spoke with had no idea if their battery was integrated at a higher than common 24V-48VDC level. I did learn that they are packaging someone else's inverter with their systems but he did not know who's inverter. Anyone out there with a SC installation that knows which inverter they are using?
Excellent thought process LolaCarChamp.
FYI: SolarCity isn't even operational in Florida--they're only in 14 states and I'd guess that FP&L's grip on the FL State legislature is quite firm. So nothing for Florida . . . sounds somewhat like NJ perhaps?
Regardless, in Texas we have a SCTY PV system (7.6 kW DC) on our roof; it's been there for almost 12 months, and we LOVE it. However, we HATE the fact that we're only getting 75% of our "push back" into the grid, once we reach 500 kWh of production and that happens every month, even with our MS.
In my quest for a solution, we found Ideal Power's site:
Ideal Power | Home
I'm so impressed I purchased about 1,400 shares a few days ago.
However, my concerns are:
1. IPWR is a very young company.
2. Are their massive efficiency gains supported by test results?
3. How much does their unique inverter cost?
My long-term goal is to capture the DC power from the PV system and shunt it to a Tesla "home" battery as well. Then any excess (beyond the MS's and home's usage/needs) was to go back to the grid. Then, when the MS returns home every night it would charge off of the DC battery first, then the grid, if additional power was still needed.
Overall, there should be a massive increase in efficiency as we're losing (ostensibly) about 15% going from the grid's 240V AC to the MS's DC battery. Even worse: I'm losing a similar (or larger?) amount of power going from the DC PV system, through our two Power One inverters, to convert the sun's power to AC/grid power, just to turn around and change it BACK to DC for the Tesla's battery!
This is borderline crazy, but it's an AC/DC world that has a lot of low-hanging fruit for efficiency gains.
I can easily see SCTY and/or Tesla buying an inverter company so that they can nip this problem in the bud; let's hope they beat us to it as I'd much prefer a turn-key solution.
Please keep us posted on how your project progresses.
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Thank you for that. I was curious how PV systems handled too much capacity (home needs X, battery is full and panels producing X + Y). I guess making heat is one way to do it.
On our SCTY PV system, any grid power loss results in an immediate and automatic PV system shut down, ostensibly for Elec Co. lineman protection. As far as I know, there is no power nor heat being generated when the system if off line.
Frankly, I don't think any power is being generated if the system is being isolated, although I do wonder why that's the case. The initial install had the panels exposed to the sun and no "shocking" occurred . . . I'd guess that there's voltage generated with solar exposure, but with no connection there's no amps flowing.
In the long-term, I expect that the ability to isolate from the grid during a local power failure AND still have some home circuits powered up (while the sun is shining, at least), will be a major selling point for SolarCity and other PV installers. I can't wait for that day to arrive as the current situation is remarkably unsophisticated.
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Oh, forgot to give you more details on the inverters SCTY installed. At least as of 12-months ago, they used:
www.power-one.com
We had to use two inverters with a 4 circuits total due to 4 different mounting angles on my roof.
Otherwise, I believe they try make a PV system work with a single inverter (for cost savings?) when the PV array will allow--one large set of panels, all on the same roof angle and without shading.