Forum Discussion

Ivylog's avatar
Ivylog
Explorer III
Nov 25, 2018

I've changed my mind about solar..900W solar install.

Over the years I’ve chosen to buy diesel instead of solar as the payback was in decades, not years; BUT times change...cost of solar less than $1/Watt. We dry camp often during the summer and by going all LED (lights and TVs) with a residential refrigerator, I've gotten my generator run time down to 1.5 hours/day...$3 of diesel so cheaper than solar as we are only half timers.

We snowbird for 3-4 months in SE Fla each winter and I’ve signed up for FPL’s (Fla Plunder & Loot) time of use program. I’ll use the MH's batteries each morning when the price/KW goes up (batteries will be fully charged on the night time rate). Hopefully, during the day, the solar I'm installing will be enough to recharge the batteries from making breakfast and run our power usage. I can always turn the power back on to top them off, before the 6PM higher rate starts or if we need AC briefly in the afternoon:

My goal is to cut my $80/month electric in half, saving me $160/winter which will pay for enough diesel to go 400 miles or 100 hours of generator time when we boondock and have to run the AC.

Just trying to help out those that say solar is the only way to go as driving a Prius or saving $160/winter with solar is not much of a offset when you have a BIG energy hog MH.
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  • Ivylog's avatar
    Ivylog
    Explorer III
    Nov 25, 2018
    I recently bought 10 102W First Solar series4 thin film panels ($550) but only have room for 7 along drivers side of my roof. They are 80V and 1.5A so I’m planning on a 60A Outback Flex Max mppt controller. Making my own tilting mounts fastened to the top of the raised rail on my 08 Navigator. Should have a little over $1000 when finished.

    At $1/Watt for the panels and controller I might have a 3 year payback as half timers and going to time of use power.

    I needed 2’ X 4’ size panels (100W) to fit along the drivers side of the MH. I realize these are not your normal mono cell panels, they are thin film. Here are the specks:
    First Solar series 4 thin film solar panels:
    NOMINAL VALUES FS-4110-3
    Nominal Power6
    (-0/+5W) PMPP (W).......... 110.0
    Voltage at PMAX VMPP (V).... 67.8
    Current at PMAX IMPP (A).... 1.62
    Open Circuit Voltage VOC (V) 86.4
    Short Circuit Current ISC (A)1.82
    Module Efficiency % ........16.7





  • Ivylog's avatar
    Ivylog
    Explorer III
    Nov 25, 2018
    There was some concern (not by me) that I needed to hold the 26 lb panels down when traveling. My roof is unusual with the raised side rails and the front and back caps are higher than the roof. I have added a 2"X 8" triangle in front of the first panel to keep air out although that far forward it's probably in a low pressure area...no lift and protected from the 70 mph winds.

    There is also a 1" opening at the top and bottom of the panels so doubt there is enough pressure under the panels to lift them up. I'll put some small pieces of paper under the bottom of the supports and if they do not blow out from under...no problem and no cord needed.

    I already knew the aerodynamic of a brick but here is a good wind tunnel test of a bus. Little or no wind at the roof on the front half of the bus. The turbulence at the back concerns me some although my roof is unusual with raised areas at the front and back so not sure if there will be any turbulence at the sunken roof level at the back.
    https://m.youtube.com/watch?v=_NPNiyR5cWo


    For those worried about the panels lifting up, I decided to run a cord from the 2x8 triangle to Eye bolts under the panels and a cord to the roof for every 2 panels to hold them down. Also added 2 more fixed panels for a total of 900W.



  • Busskipper's avatar
    Busskipper
    Explorer
    Nov 25, 2018
    Ivylog wrote:
    Over the years I’ve chosen to buy diesel instead of solar as the payback was in decades, not years; BUT times change.

    We snowbird for 3-4 months in SE Fla each winter and I’ve signed up for FPL’s (Fla Plunder & Loot) time of use program. I’ll use the MH's batteries each morning when the price/KW goes up (batteries will be fully charged on the night time rate). Hopefully, during the day, the solar I'm installing will be enough to recharge the batteries from making breakfast. I can always turn the power back on to top them off, before the 6PM higher rate starts or if we need AC briefly in the afternoon:

    My goal is to cut my $80/month electric in half, saving me $160/winter which will pay for enough diesel to go 400 miles or 100 hours of generator time when we boondock and have to run the AC.

    Just trying to help out those that say solar is the only way to go as driving a Prius or saving $160/winter with solar is not much of a offset when you have a BIG energy hog MH.


    Dick,
    Will be interesting to see how you do on the PayBack Calculations :)

    8 - 10 nights with A/C and the Generator and you lose the year - think the Prius is the better PayBack - :)

    But it's the thought that counts - Now if you could get the Prius as the Electric Generator for the Coach - That might just be a real Saver.

    Just messing with you, Hoping you had a great ThanksGiving and enjoy the Winter in Warm Sunny Florida.

    Set Up Looks/Sounds great!

    Bill
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Nov 25, 2018
    “Hopefully, during the day, the solar I'm installing will be enough to recharge the batteries from making breakfast and run our power usage.”

    With 900 solar watts in Florida recharging won’t be an issue.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Nov 25, 2018
    “There was some concern (not by me) that I needed to hold the 26 lb panels down when traveling”

    Ivy, ask those who are worried about panels blowing off how many they have seen along the road. Me? Zero.
  • Ivylog's avatar
    Ivylog
    Explorer III
    Nov 25, 2018
    Bill, doubt a non DIY solar installation has a payback as they are 4X times more expensive plus the cost of the extra batteries needed to make it work...$$$$. If I had not found panels at 55 cents/watt and going to time of use power; I probably would not have bothered with this project. I have also found 12V AGMs for less than $1/AH.

    How much longer are you building? Stay warm as my WX guy says it’s going to be cold in the East.
  • Busskipper's avatar
    Busskipper
    Explorer
    Nov 25, 2018
    Ivylog wrote:
    Bill, doubt a non DIY solar installation has a payback as they are 4X times more expensive plus the cost of the extra batteries needed to make it work...$$$$. If I had not found panels at 55 cents/watt and going to time of use power; I probably would not have bothered with this project. I have also found 12V AGMs for less than $1/AH.

    How much longer are you building? Stay warm as my WX guy says it’s going to be cold in the East.


    Built out here in Maryland - two for sale - One son trying to get me to Build one in Amelia Island for Winter and the other Has property in Red Cliff, Colorado for Summers.

    DW just wants to be Close to Granddaughters so - the next moves will be interesting to say the least.

    For me, I could be happy with a 24x50 pole barn with a small apartment Attached - not sure that's in the Future as the DW just has a fixation with the Sticks and Bricks. :)

    I did the 500 watts and Outback 15 years ago - doubt I have even saved 20 percent of the installation cost. :) But I helped save the Planet.

    Simple for me - just get some elevation - and some of the Colorado Rockies - hard to Beat, just pull up the blankets and Enjoy Life.

    Will continue to follow you Solar Adventure (Still think they will lift - :) )

    Bill
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Nov 25, 2018
    If you have an inexpensive dash camera that you could temporarily mount on your roof, you could easily set up a series of cloth strips to indicate roof turbulence. I used to do this with a few airplanes that I owned. In your case I would basically just take a strip of cloth, about 12" long, and tape it to the roof in various locations. Tape only the end near the front of the coach. With the dash cam running, you drive the coach and you can see the air turbulence by the way the cloth strips move. Not very scientific but if you see a few strips dancing all around, you know that you have some serious winds. If they all just lie flat, or trail straight back, things are fine. If the strips lift and seem to act like they are trying to take off, that is an indication that you have an uplift situation and you may have to make sure that your panels are fastened securely to keep them in place. Have fun. :B
  • Ivylog's avatar
    Ivylog
    Explorer III
    Nov 25, 2018
    2oldman wrote:
    My solar usage is not as much about money as yours.

    I looked at a lot of your previous solar posts trying to understand your statement without much luck. As a business owner the costs/benefits and payback of something is important to me and it sounds like it is not for you??? I find the “feel good” portion of solar to be hypocritical from anyone with a RV, especially a big energy hog MH like mine. Will 900W of solar make me feel good??? When it’s hot out, only my 10K generator will do that.

    The point of starting this post is that cost of solar has gotten cheap enough (IF you DIY) that it can actually make economic sense. Hopefully, those on the fence will decide to add some solar to their RV and get away from FHU camping.

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