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  • NWFPat
    replied
    Right, so there is no advantage to a higher output, more expensive panel? The ONLY thing that counts is the lowest cost per kW AC at a point as close to the max output for Tier 1 (in this case), as possible? I am also thinking Gulf Power may allow one to round down if a particular configuration of panels goes over the tier limit ...

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  • Ampster
    replied
    Originally posted by NWFPat View Post
    Gulf Power docs say, “For inverter-based systems, the Gross Power Rating shall be calculated by multiplying the total installed DC nameplate generating capacity by .85 in order to account for losses during the conversion from DC to AC)."

    Doesn't this mean the rated power output of the panels?
    I made that assumption based on post # 4 but after rereading the entire thread you subsequently quoted there document which stated it very clearly to be based on panel capacity. I will delete my post since it is irrelevant.
    Last edited by Ampster; 04-06-2021, 08:18 PM.

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  • NWFPat
    replied
    Gulf Power docs say, “For inverter-based systems, the Gross Power Rating shall be calculated by multiplying the total installed DC nameplate generating capacity by .85 in order to account for losses during the conversion from DC to AC)."

    Doesn't this mean the rated power output of the panels?

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  • NWFPat
    replied
    Gah - sorry - too quick!

    Forgot the DC to AC thing

    So, 31 panels ... (31x380x0.85) = 10013

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  • NWFPat
    replied
    Well, interesting morning - one of the companies proposing is saying the Hanwha Q Cell 340W panels are leaving production - and the G9 in 380 is what they are now proposing, so my attempt to neutralize the bids won't work ... anyone heard this about the 340?

    With 380s would be 26 panels (to stay under the Tier 1 Gulf Power limit), and the IQ 7A would be used vice IQ 7+.

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  • bcroe
    replied
    Originally posted by NWFPat View Post
    Continuing to read, looking for some goodness to upgrading panels for power output (fewer so lower labor), lower degradation (power at end of warranty), better temperature characteristics (Florida) ... not sure I have found anything that leads me down the path of paying more ... am I missing anything?
    Published numbers may vary some, the reality is probably much closer to, they
    are all the same. Here the plan has been to use the most generic, highly
    produced/lowest price per watt panel, which has been the 60 cell (10 X 6)
    250+ W. The 72 cell may come close, I find them far harder to hoist into
    place, both size and weight increase.

    15% losses, with good design attention and good inverter, mine are only
    about half that. good luck, Bruce Roe

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  • Ampster
    replied
    Originally posted by NWFPat View Post
    Continuing to read, looking for some goodness to upgrading panels for power output (fewer so lower labor), lower degradation (power at end of warranty), better temperature characteristics (Florida) ... not sure I have found anything that leads me down the path of paying more ... am I missing anything?
    I have used everything from SunPower panels, to Hanwha panels to the least expensive Canadian Solar panels. The only reason I picked Sunpower panels is I was space constrained. In the long term I cannot offer any further analytical evidence. The cost per installed Watt has decreased over that same time frame so it is a moving target.

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  • NWFPat
    replied
    Continuing to read, looking for some goodness to upgrading panels for power output (fewer so lower labor), lower degradation (power at end of warranty), better temperature characteristics (Florida) ... not sure I have found anything that leads me down the path of paying more ... am I missing anything?

    Leave a comment:


  • Ampster
    replied
    Originally posted by khanh dam View Post
    build a pergola in your back yard, ......
    Originally posted by nwfpat View Post
    i don't have space for a ground mount .
    Q.e.d.
    Last edited by Ampster; 04-02-2021, 02:19 PM. Reason: QED

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  • khanh dam
    replied
    build a pergola in your back yard, if that gets rid of the ridiculous insurance upcharge! $250x 20 years is $5000, which is more money than what the panels cost per watt. $5000/11,000w = $0.45/w and they are only worth $0.37/w

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  • NWFPat
    replied
    Absolutely, but I don't have space for a ground mount . If I had I would build it out myself and get electrician to do the final connects - would solve a lot of problems!

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  • bcroe
    replied
    Originally posted by SunEagle View Post

    That is sad about your insurance increase. I guess everyone needs to figure
    some type of cost increase for insurance in their ROI just to be safe.
    I am adding that as # 50 to my list of advantage to a ground mount. Bruce Roe

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  • NWFPat
    replied
    Just ran the numbers, again - puts payback right at 11 years ... next angle is to go to Tier 2, with more panels up to the 40 (31-40) that USAA uses for the rate increase, then determine whether the $3M umbrella policy I already have with USAA is sufficient for Gulf Power for the Tier 2, then add in cost of the additional panels/inverters to determine if it makes sense to make power at 2.02 cents per kw - maybe $40/month max with 340W panels, or $78/month with 385W panels ... math gets harder ...

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  • SunEagle
    replied
    Originally posted by NWFPat View Post
    Looking through Gulf Power docs - this in there - explains why the proposals are rounded to this number vs working with exact inverter efficiencies to determine tiers?

    "For inverter-based systems, the Gross Power Rating shall be calculated by multiplying the total installed DC nameplate generating capacity by .85 in order to account for losses during the conversion from DC to AC)."

    Also had a very unsatisfactory discussion with USAA about insurance cost increases - they sort by the number of panels only (ie 1-10, 11-20, 21-30, 31-40) vice power output or cost - so, a $20.000 system will increase insurance basis on the house by $73,000 - about $250 a year increase in premiums.
    That is sad about your insurance increase. I guess everyone needs to figure some type of cost increase for insurance in their ROI just to be safe.

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  • NWFPat
    replied
    Looking through Gulf Power docs - this in there - explains why the proposals are rounded to this number vs working with exact inverter efficiencies to determine tiers?

    "For inverter-based systems, the Gross Power Rating shall be calculated by multiplying the total installed DC nameplate generating capacity by .85 in order to account for losses during the conversion from DC to AC)."

    Also had a very unsatisfactory discussion with USAA about insurance cost increases - they sort by the number of panels only (ie 1-10, 11-20, 21-30, 31-40) vice power output or cost - so, a $20.000 system will increase insurance basis on the house by $73,000 - about $250 a year increase in premiums.

    Leave a comment:

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