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Tesla Solar Panels

Discussion in 'Tesla Energy' started by Piney999, Jun 9, 2018.

  1. Rockster

    Rockster Active Member

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    Tesla quoted me about the same, $3.15 to $3.30, depending upon the specific system size and panels selected. I shopped around and found a local company that installed my 10k system for $2.50/watt, total, before tax credit. I wanted to give Tesla the $$$, but I couldn't justify paying an additional $6k to $8k for an equivalent system.
     
  2. MorrisonHiker

    MorrisonHiker S 100D 2020.40.8

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    I'd like to point out that a couple of messages above mentioned "Tesla uses 325W panels" or "Tesla uses 315W" panels". It depends! When we first got started, we were told we could get 305W panels and the manufacturer could vary from half a dozen different manufacturers. If we wanted the best they offered, we could get the 325W Panasonic panels made at GF2 with a longer warranty. We later saw others mention the 315W Panasonic panels. We asked about those and they said we could get those and while they look better, they aren't as efficient as the 325W panels. Since the 325W panels were only about $10 more per panel than the 315W panels, we decided to stick with those.

    So...be sure to ask if different panels are available and they'll be able to give you a cost for whatever W panel you are interested in.
     
  3. NuShrike

    NuShrike Member

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    As long as the small-text on this performance guarantee is understood well:
    SolarCity Warranty & Performance Guarantee Explained | Solar News

    I personally like a warranty where they fully cover removing, shipping, replacement of a panel on an fault vs credit back (to zero) which is offset by any over-performance by the total system.
     
  4. DrComputer

    DrComputer Active Member

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    It seems the industry loves to quote with price-per-watt numbers yet that doesn't really do much to let the consumer compare apples-to-apples. I recently expanded my 8-year-old solar system (6.6KW) with an additional 3.3KW parallel system. My current system was installed by REC Solar (now called SunRun) and they refused to upgrade or install a parallel system (so did Tesla/Solar City). So I got quotes from several small local solar companies. I specified everything for the system (Panasonic 330W panels, SMA inverter, Tigo optimizers, panel and string layout). You really need to look at what specific things each installer is quoting. Just comparing price-per-watt is like car shopping and just looking at models with the same horsepower. I would never install a solar system without optimizers (like Tigo or SolarEdge) and only get high-quality panels (like the Panasonics with a 20 year parts AND labor warranty).
     
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  5. jrmnet

    jrmnet Member

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    This was at the Telsa dealership office in SF. They had sent out and email invite. More info here, but I don't think it is always up to date:
    https://www.tesla.com/events
     
  6. jgd108

    jgd108 Member

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    I was quoted last week the Panasonic 325W but at a ridiculous cost of $4.27 / W !!
    They keep saying we will match any quotes you send.
    So far I'm getting $2.90 for same system (panels and solar edge inverter)
    Will see if they really match it.
    Tesla warranty seems good?
     
  7. nwdiver

    nwdiver Well-Known Member

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    #27 nwdiver, Jun 12, 2018
    Last edited: Jun 12, 2018
    Why? For most systems they don't make much of a difference... certainly not enough to justify spending ~$0.05/w...

    This is the production last month by panel for one of our SMA systems. I did an experiment and installed an optimizer on one of the panels... the others just have a TS4-S... guess which one is optimized (hint: it's not the best performing one)

    Panels.jpg


    Optimizers work by allowing each panel in a string to operate at its optimal voltage and current point. The tolerance for panels are tight enough that this makes little to no difference as can be seen in these two independent but identical system. You can see how the current and voltage curves overlap. Optimizing each of these 96 panels would have cost ~$5k and yielded very little additional production if any...

    MPP.jpg
     
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  8. VT_EE

    VT_EE Active Member

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    If you have any shading, you want optimizers. They also help you figure out how each individual panel is performing. I’ve been very happy with my Sunpower/SolarEdge setup.
     
  9. nwdiver

    nwdiver Well-Known Member

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    #29 nwdiver, Jun 12, 2018
    Last edited: Jun 12, 2018
    'Next Gen' inverters have a separate tracker for each string. A MPPT for each string handles shade just as well as an optimizer on each panel at a fraction the cost. String level optimization is worth it for shading issues but there's no additional benefit to module level optimization. I agree that the ability to monitor performance on the module level is cool but it's also unnecessary.

    This array does experience some shade... handles it just fine... optimizers wouldn't help. String level optimization is all that's needed...

    Screen Shot 2018-06-12 at 7.39.01 PM.png
     
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  10. VT_EE

    VT_EE Active Member

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    It’s still a string though, and shade on a couple panels will torch the efficiency of the effected string even if the other is not affected. I have numerous pipes and a chimney on my roof that shade various panels throughout the day. Unless there has been some magic solar panel redesign in the last couple of years (since I last researched this), shade on any panel in a string will increase the resistance of the entire string and reduce the power output of all its panels. Optimizers break a string of panels wired in series into a bunch of individual panels wired in parallel, all operating independently. Now only the shaded panel is effected instead of the entire string.
     
  11. nwdiver

    nwdiver Well-Known Member

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    #31 nwdiver, Jun 12, 2018
    Last edited: Jun 12, 2018
    The 'magic' you're referring to is a bypass diode. They basically split every panel into 3rds vertically. If the path of least resistance isn't through the cells the bypass diode becomes a short and shunts current around the shaded area. This CAN be an issue if you have 2 or more parallel strings on 1 tracker since now the unshaded string is forced to operate at a lower voltage which is why I emphasized 'string level optimization' you can see the bypass diodes at work in the screenshot I posted. The unshaded panels are completely unaffected by the 2 shaded panels... only the panel in the bottom string 2nd from the left is equipped with an optimizer and it has the same power output as its unoptimized siblings. If each string is on an independent MPPT shade has zero effect on unshaded panels.

    ALL solar panels have bypass diodes. Without them a leaf could cause a fire... the shaded area is basically 'deleted' from the string. The same thing occurs with an optimizer...

    [​IMG]

    [​IMG]

    The first array I built I actually had to install my own bypass diodes. It was kinda cool to watch them work. It really is like 'magic'.... you put a multimeter across the cell line and start shading that section with your hand. You'll see voltage start to drop... then go 'negative' as the cells become a load... then voltage will fall to ~0 as the diode starts to conduct. MAGIC!
     
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