My solar setup thread

Discussion in 'Power - Site Power/Batteries/Generators/Solar' started by Strut, Aug 12, 2014.

  1. Strut

    Strut Member

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    Jun 24, 2014
    I thought I'd share my plans and thoughts as I wrap-up my solar install. I've posted a few times on my planned setup before, but I figured I might as well make a thread to share in my progress. I figure I may have a few questions or ask for advice on the way.

    This is a picture of the 20A MPPT charge controller I went with. This is the only affordable controller I found that had a remote meter. The meter will be installed right inside the door so I can check the system status while the roof is down. The charge controller and sealed battery will be installed inside in a cabinet directly above the axle. The battery pictured is a small 35AH AGM battery I use in my greenhouse, it is not going in the PUP. The cable is 10G with splitters for my two 100W Mono panels. The inverter is just a cheap 200w model that I plan on keeping around just in-case a need arises, I doubt I install it permanently.

    [​IMG]

    Here is a pic of the panels and the no-drill mounts I found

    [​IMG]

    I'm going to have to put one hole in the roof to route the panel wires to the controller. Note the wire cover meant to seal this up. I'm still working out where and how I will route these wires both inside and out to get the clean install I'm looking for.

    More to come.

    Cheers,
     
  2. SirLancelot

    SirLancelot Member

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    Sep 28, 2010
    What kind of mounts are those? I'd be a little bit worried about a panel flying off at 65mph on the freeway. What kind of setup do you need 200W for? I have a 100W Renogy panel that is more than ample for my interior lights, water pump, charging various electronics, etc. Just curious as I know everyone has a different setup.
     
  3. Ponyknite

    Ponyknite New Member

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    Jul 6, 2014
    This I might consider for my pup upgrade when I'm done with the reconstruction.
     
  4. Strut

    Strut Member

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    Jun 24, 2014
    I went with Renogy panels myself. I opted to spend the money for extra capacity for several reasons:

    The panels would be installed flat on my roof, and often in shade. Even in full shade these panels and the MPPT controller will charge a 12v battery surprisingly well.

    The cost of my 200w, MPPT, piece meal system was less than commercial systems with less than half the capacity. I don't expect to ever need the full 200w, but I'll be happy to have the power if I ever do. Again, my objective is to have enough power even in sub-optimal conditions.

    I'll have to get back to you on the manufacturer of the mounts, I can't get into my notes tonight for some reason. I did a bunch of research on them, their surface area, and more importantly the adhesive, and they will hold up just fine to highway speeds. I was a bit worried myself at first.

    Another reason I opted for the roof mount design is that with the PUP deployed I won't have to worry about the panels wandering off, as you can't even see them from the ground. When I camp I'm rarely around the campsite during the day, which makes it hard to chase the sun with mobile panels.


    I hope this answers your questions. I'll get back to you on the mounts.
     
  5. Strut

    Strut Member

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    Jun 24, 2014
    I'm debating a reconfiguration of the PUPs 12v system to route all 12v loads through the solar charge controller so I can use it's features to monitor my usage. The controller is rated for 20A on the load side so I'm fine there. I guess I would need to isolate the controller and battery from the converter's 12v supply for the rare case that I'm plugged in somewhere. Has anyone here done anything similar? Did you use a diode, mechanical, or other form of isolation?

    Here is the info on the panel mounts
    http://www.amazon.com/gp/product/B008LMIHNQ/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

    Adhesive
    http://www.amazon.com/gp/product/B00C501KD4/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
     
  6. RangerZ

    RangerZ Member

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    Oct 11, 2012
    Thank you for sharing the panel mount and adhesive links!
     
  7. Strut

    Strut Member

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    Jun 24, 2014
    I just realized the I haven't mentioned my battery situation. The PUP came with a standard group 24 flooded battery that is a bit too small for my needs. I also need to lighten up the tongue a bit, so my plan is to install a sealed AGM battery in the cabinet above or just aft the axel. This also give me the benefit of using the temperature compensation feature of the charge controller as it will be installed in the same space as the battery.

    I have a couple of ~125AH AGM batteries that came out of a giant UPS system used in Data Centers. The problem is that they are close to 8 years old and loosing capacity. I wouldn't be surprised if the new group 24 I have is the better of them. If I could install both I could probably get another year or two out of them, but at somewhere north of 100lbs each that isn't going to be possible. So now I'm looking at a new sealed/AGM battery, and they are $$$.
     
  8. speckhunter80

    speckhunter80 Well-Known Member

    Under ideal full sun conditions you should get 11.1-11.2amps per hour from your set up
     
  9. dcel

    dcel New Member

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    May 20, 2013
    Great install ! I love the "al-a-carte" and the way you attached the panels to the roof.

    Do you have a link to your panels? and a link to your charge controller?
     
  10. MandoCamper

    MandoCamper Member

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    Jul 14, 2013
  11. speckhunter80

    speckhunter80 Well-Known Member

    How many amps will your solar panels produce? Will it be less then 10 amps?
     
  12. SirLancelot

    SirLancelot Member

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    Sep 28, 2010
    Thanks for the link to those mounts. At some point we're going to go to the dark side (sell the popup and buy a TT) and mounts like that will be awesome. Perhaps I went with more of a simplistic route, but I mount the panel the my roof on the factory roof rack (tied down with paracord and fancy Boy Scout knots), run the power cord down from the roof and Velcro strap it to one of the roof supports, hang the charge controller from under the front bunk near the battery and connect it to the battery from there. One 100W Renogy panel full charges our Group 27 battery by 10 or 11AM even on cloudy days. I couldn't be more pleased with it. I imagine a second 100W panel may be handy when we do go the dark side, but for now 100W is MORE than ample. A hard-wired voltmeter I installed inside the door helps me see where we're at any time of the day/night.
     
  13. MandoCamper

    MandoCamper Member

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    Jul 14, 2013
    I have a 90 watt system, which produces less than 10 amps.
     
  14. chipperone1

    chipperone1 Member

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    Aug 27, 2011
    Cool!

    How did you figure that?
     
  15. Strut

    Strut Member

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    Jun 24, 2014
    Ohm's Law

    Amperes = Watts/Volts

    200w / 12v = 16.7 amps

    This is of course under ideal circumstances.

    I haven't hooked everything up to see exactly, but I imagine I'll get around 11 or 12 amps with the panels flat here in KY. I'll test some this afternoon.
     
  16. Strut

    Strut Member

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    3
    Jun 24, 2014
    Well I setup the panels this afternoon and of course it is rainy and overcast. The first thing I realized is the controller meter only displays the incoming power from the panels as volts... not particularly helpful in our Amp Hour world.

    I put on my other engineer hat (I'm a software engineer), and dug out some texts on the subject. I could chart out the Amperes if I had a few resistors, problem is the 1/4 watt resisters I have laying around for my Arduino projects aren't going to cut it. I could also measure the resistance of the circuit and work out the amps, which I may do once the system is installed, but right now that wont tell me a whole hell of a lot. The product data sheet already tells me most of what I'd be able to deduce.

    I can tell you this however, its overcast and raining and I'm measuring 16-18v at the controller and my little 35AH battery that was showing a 55% SOC is now almost full. The controller does measure amps at the battery, and the few times I checked at the start it was showing about 2. It is now trickle charging with 13.3v at 0.5amp or so. This measurement is just what the controller is supplying to the battery for charging. It looks like the battery amps can go negative depending on load which could prove informative.

    Now I just got to get this equipment installed and she how she does. Probably won't happen until next week though.
    [​IMG]
     
  17. chipperone1

    chipperone1 Member

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    Aug 27, 2011
    Thanks, I get the Ohm's Law part but I don't get how both equations figure ideal conditions but have different answers.

    You got 16.7 amps and the other answer was 11.1 - 11.2 amps.

    I am curious and waiting to see the results of your testing.
     
  18. Strut

    Strut Member

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    Jun 24, 2014
    The 200w rating of the panels is under completely optimal conditions, with full sunlight hitting the panel perfectly perpendicular.

    I'm located quite a bit above the tropics so I'm never directly under the sun, plus I'm mounting the panels flat and not keeping them pointed at the sun. This is why I'll never reach the panels full potential, and why I went with two.

    I think SpeckHunter was referring to the full sun available to me? I think his numbers are close to about the best I could expect. If I get half that in real use I'll be happy.
     
  19. speckhunter80

    speckhunter80 Well-Known Member

    Strut, I believe your calculation is incorrect. You need to look at the output of the solar panels which in most cases is 13.5 volts therefore 200 watts divided by 13.5 = 14.8 But I apply an inefficiency factor of 75% So 14.8x.75=11.11
     
  20. Strut

    Strut Member

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    3
    Jun 24, 2014
    You're absolutely correct. I thought that sounded really high. I had done the calculations previously with irradiance data for my location and came up with a number very close to yours.

    To find the actual current you would need to measure the voltage coming from the panels, then measure the resistance in the circuit and divide the results.

    I just pulled up the data sheet for these 100w Renogy panels. Vmp is 18.9v, so 200w/18.9v = 10.58A at 1000W/m2 irradiance.
     

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