Forum Discussion

bob_nestor's avatar
bob_nestor
Explorer III
Apr 12, 2014

Another Solar mod with questions

I've got a Roadtrek 210 that I do a lot of dry camping with so power is sometimes an issue. It came with US 1800 XC batteries (208 A/hr) that recently were replaced with US 250 HCXC2 (280 A/hr). They just barely fit. :-) I also have a portable 120W solar panel that I've used on the last two camping trips. It seems to do a good job of keeping the batteries up and they appear to be fully charged by 10am even on cloudy days.

So now I'm looking at installing something permanent on the roof. I don't want to drill holes so I'm looking at some glue-down semi-flexible panels. Home Depot has some 100w panels and I could fit two in the space. I've also run across some 135W panels being manufactured in China that are about 56x21 in size and I could fit two in the space available. I can't find them being sold by any vendor here in North America, although they have been in the past (discountsolar). I'm hesitant about ordering direct from China - I tried and they processed my credit card, then cancelled the order for "security reasons". Now they want a lot more personal information which I'm not comfortable giving, things like bank statements, driver's license, partial credit card numbers, etc.

Oh, I'm trying to go for max solar here to compensate for losses. I've read there's about a 9% loss for glue-down, up to a 50% loss in winter months, etc. My plan is to use an MPPT controller to try and maximize my harvest utilizing what little space I have available.

Does anyone know of a vendor here in North America currently selling these semi-flexible 135W panels at a somewhat reasonable price? I was looking at about $580 for two with shipping direct from China.
  • Redsky's avatar
    Redsky
    Explorer
    Apr 17, 2014
    Those glue mount spoilers look like a great solution for mounting on a metal roof. With any mount it might as well be permanent and look professional as the solar setup should help and not hurt resale value if that is important.

    The comment on only 12 amps misses the point that it is 12 amps per hour. With 6 hours of daylight that becomes 72 amps of charge for the batteries. With a Class B MH it is hard to see how the usage will ever be more than that. The most we have ever used, winter or summer is 48 amps in a night and the two 6+ amp panels had the batteries back at 100% in less than 4 few hours.

    The place to start with this kind of project is with the installation of a good digital charge meter so you know what is drawing how much and how effective the vehicle's charging system is in recharging the house batteries by itself.
  • bcsslc's avatar
    bcsslc
    Explorer
    Apr 13, 2014
    Try this....Unisolar 128 Watt Flexible Solar Panel PV Laminate - Simple & Easy Installation - Peel & Stick

    Sound to good to be true but its not.. do some looking around and you will be very pleased.
  • wmoses's avatar
    wmoses
    Explorer
    Apr 13, 2014
    bob_nestor wrote:
    Murphy is 5 miles east of Plano, 5 miles west of Wide Awake Wylie, 2 miles south of Southfork Ranch in Parker, a block north of Sache, kiddy-corner from Garland and just across the street from Richardson. Does that help? LOL

    Almost got it. ;)
  • bob_nestor's avatar
    bob_nestor
    Explorer III
    Apr 12, 2014
    pianotuna wrote:
    Hi Bob,

    I'd try to squeeze 200 watts onto the roof. I believe Landyacht has Chinese panels that were cut to size for him. (I may have the nick name wrong).

    http://www.link-solar.com/category/flexible-solar-panel/sunpower-cell-high-efficiency-flexible-panel/


    Thanks. Yeah, I can easily get 200W up there but with the 135W panels (1540x540x3mm) I can just squeeze in 2 and get 70 more sun robbing watts of power.

    I've also found Link-Solar but they don't seem to have a way to buy them on their web page. From what I can tell it looks like they'd like to sell volume lots to resellers. I just need two, but they do have exactly what I'm looking for. I just need to figure out out to order them.
  • bob_nestor's avatar
    bob_nestor
    Explorer III
    Apr 12, 2014
    wmoses wrote:
    Try Go Power.

    If I knew where "Murphy" was (as stated in your profile) I could give you a more local link.


    I've looked at GoPower and all they offer is 2x100. I already have a couple of vendors for those size that will fit. What I'd really like to do is put as much on the roof as I can. The 135W panels I found in China are 56x21 inches. I've measured the space I have and I have about 56x42 inches without hanging down the side where they'd be viewable. Two 135W panels would give me 270W.

    Murphy is 5 miles east of Plano, 5 miles west of Wide Awake Wylie, 2 miles south of Southfork Ranch in Parker, a block north of Sache, kiddy-corner from Garland and just across the street from Richardson. Does that help? LOL
  • pianotuna's avatar
    pianotuna
    Nomad III
    Apr 12, 2014
    Hi Bob,

    I'd try to squeeze 200 watts onto the roof. I believe Landyacht has Chinese panels that were cut to size for him. (I may have the nick name wrong).

    http://www.link-solar.com/category/flexible-solar-panel/sunpower-cell-high-efficiency-flexible-panel/
  • RoyB's avatar
    RoyB
    Explorer II
    Apr 12, 2014
    Your ROADTREK does not have a very large area to mount solar panels.

    Keep in mind that what ever you pull from your batteries you have to put back in. The 100W type SOLAR panels only give you around 5-6AMPS DC CURRENT during high sun to charge your batteries with. A couple of panels is not going to produce much more than 10-12AMPS DC CURRENT so this relates to taking a long time to get your batteries charged back up to their 90% charge state before you can use them again at almost full performance. You will run out of usuable HIGH SUN with only 5-6 hours time during the day.

    Your question is going to be will 12AMPS replace the power I pulled out of the bank bank before it gets dark on you.

    Need to do some reading up on how solar works for you. Your SOLAR CONTROLLER will perform much like your on-board CONVERTER/CHARGER. If you are expecting to re-charge your batteries in a three hour time frame like you can do with shore power/generator running your on-board smart mode converter/charger than many 120WATT Solar Panels will be required to get the right amount of DC CURRENT to satisify your battery bank demands when they are hit with 14.4VDC Boost charge volatges. The rule of thumb is 15-18AMP per 12VDC (typical 110AH type) Batteries in your battery bank. I am not amiliar with your present batteries being used. If your batteries are always up in charge most of the time then the couple of 100WATT solar panels will be great to keep them topped off during the high sun daylight hours.

    Will take some looking into to be successful...

    Roy Ken
  • wmoses's avatar
    wmoses
    Explorer
    Apr 12, 2014
    Try Go Power.

    If I knew where "Murphy" was (as stated in your profile) I could give you a more local link.

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