Solar Pannel for an rv

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  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv
    lolcashcow wrote: »
    Hi Cariboo!

    Then if I use a PWM CC it will only perform at 84 watts? I could use it that way as a temporary solution until I can gather up the needed cash for an MPPT? When you say that it is a "Real" 24V panel ... does it mean I can use an MPPT CC that covers up to 24v?

    The cheapest MPPT for a 24v that was listed earlier was the morningstar sun saver

    http://www.solar-electric.com/mosumpsochco.html

    Thank you SO much BB for that amazing list you made for me :) Highly appreciated !

    In this case "real" means a panel that could be used on a 24 Volt system with a PWM type charge controller as opposed to some "24 Volt" panels which have only a 30 Vmp (or even less).

    As-is you get 4.8 Amps. Not very much for doing anything with.

    On a small MPPT type controller like the Morningstar 15 you'd get about 10 Amps. Good enough for 100 Amp hours of 12 Volt battery.

    Bill always knows where to find things. Me, I'm lucky if I can locate my socks. And that's when they're on my feet. :D
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    If it's hot out and you have a long wire run then performance on a 24V system might be similar with a PWM and an MPPT controller. It will not work well with a 12V panel without an MPPT.



    Because it is generally plastic (or more accurately Tedlar or a similar material) that is not as damage resistant as the glass on the front.

    Hi Bill!

    Thank you for letting me know about the material on the back :). It is also good to know that the panel is tough at the front... makes me feel slightly better after it accidentally dropped. Though that was a big no-no on my part :(.

    I was thinking on setting up this panel with really short wires of a foot or less in length. I read online that less length = best to get the most out of the system. So Less than a foot long wires to connect it to the battery.

    When you mentioned that It will not work well with a 12V panel without an MPPT this means that if I try to hook up this panel then add another panel that is 12v performance will be compromised unless i upgrade to a MPPT CC?

    I was considering on the panels from this kit at harbor freight. The shop is located like 5 blocks from where I am parked

    http://www.harborfreight.com/solar-panel-kit-45-watt-68751.html

    They also have a charge controller

    http://www.harborfreight.com/30-amp-solar-charge-controller-68738.html

    and other goodies too

    http://www.harborfreight.com/solar-panels.html
    In this case "real" means a panel that could be used on a 24 Volt system with a PWM type charge controller as opposed to some "24 Volt" panels which have only a 30 Vmp (or even less).

    As-is you get 4.8 Amps. Not very much for doing anything with.

    On a small MPPT type controller like the Morningstar 15 you'd get about 10 Amps. Good enough for 100 Amp hours of 12 Volt battery.

    Bill always knows where to find things. Me, I'm lucky if I can locate my socks. And that's when they're on my feet. :D

    Hi Cariboo

    Okay so then at 4.8amps it will give around 84 watts and at 10 amps ... it will give close to its full potential :)? I would guess at least? Most of the time you only get about 90% out put or at least I read online?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv
    lolcashcow wrote: »
    Hi Cariboo

    Okay so then at 4.8amps it will give around 84 watts and at 10 amps ... it will give close to its full potential :)? I would guess at least? Most of the time you only get about 90% out put or at least I read online?

    Yep. On the MPPT with 10 Amps out it's roughly full power (10 Amps * 17-ish Vmp = 170 Watts).
    On average a panel produces about 80% of its power rating with a bit more loss for the controller, which is why we calculate average array output over hours of "equivalent good sun" as 77% nameplate rating.

    In this case the wire length doesn't make much difference as the panel's actual Voltage is much higher than the charging Voltage so V-drop doesn't really enter in to it.

    Avoid the Harbour Freight stuff; it's less than stellar.
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    Yep. On the MPPT with 10 Amps out it's roughly full power (10 Amps * 17-ish Vmp = 170 Watts).
    On average a panel produces about 80% of its power rating with a bit more loss for the controller, which is why we calculate average array output over hours of "equivalent good sun" as 77% nameplate rating.

    In this case the wire length doesn't make much difference as the panel's actual Voltage is much higher than the charging Voltage so V-drop doesn't really enter in to it.

    Avoid the Harbour Freight stuff; it's less than stellar.

    Oh, is it? I might be able to get my hands on the set of panels in that picture for a really low cost from someone I know. If I were to hook the 170 watt panel that I received and the set of (15*3) 45 watt from a friend that would make a nice 215 watts!

    Would you advice that it would be a good idea to get the sunstar saver MPPT controller for either the single set up of the 170 watt panel or the other possible set up with the added (3*15) 45 watt panels? In other words... would the MPPT be able to handle all of these panels together?

    "This MPPT charge controller will handle up to 200 watts for 12 volt systems, or 400 watts for 24 volt systems. This controller is ideal for those of you that got those high voltage panels at a great price and then found out it was not a 12-volt panel...

    This is the ideal controller for many small systems where the cost of one of the large MPPT controllers is not justified.

    This controller can be used for 12 or 24 volt battery systems, with panel voltages up to 75 volts (3 12-volt panels in series). This is the controller we recommend where you are using one of the larger grid-tie type panels such as the Kyocera KD or other panels that have Vmp higher than 18 volts or so.

    This controller is the most efficient solar charge controller available for smaller systems.

    5 year warranty"

    http://www.solar-electric.com/mosumpsochco.html
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv

    The 200 Watt rating for the MS 15 MPPT is a sort of 'guideline' based on 15 Amps output current (15 * 12 = 180). In reality with average panel performance you can put more on the input because it won't be producing the nameplate rating anyway. More like 234 Watts. Any 'extra' power is just 'clipped'.

    Notice how the HF stuff doesn't even give you real specs? Not sure what the Voltage is, but if you parallel another panel with the 170 the Vmp has to be very close; you can't put a 17.5 Vmp panel in parallel with a 35.4 Vmp panel; the lower Voltage panel will be pulled above its power rating so far that it will effectively produce no current at all (like it would at Voc).

    Anyway, the right paneling is still dependent on the battery capacity. Without knowing that it's all speculation.
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    The 200 Watt rating for the MS 15 MPPT is a sort of 'guideline' based on 15 Amps output current (15 * 12 = 180). In reality with average panel performance you can put more on the input because it won't be producing the nameplate rating anyway. More like 234 Watts. Any 'extra' power is just 'clipped'.

    Notice how the HF stuff doesn't even give you real specs? Not sure what the Voltage is, but if you parallel another panel with the 170 the Vmp has to be very close; you can't put a 17.5 Vmp panel in parallel with a 35.4 Vmp panel; the lower Voltage panel will be pulled above its power rating so far that it will effectively produce no current at all (like it would at Voc).

    Anyway, the right paneling is still dependent on the battery capacity. Without knowing that it's all speculation.

    Hi Cariboo,

    You did mention that before. Sorry I was just so happy riding the Wattage Train I forgot about that little detail. Then I would have to set up the 45 watt panel set individually... or would it be possible to have the 170w with its on CC and the 45w with its own CC but connect both panels to a single battery? I think that thought is border line frankeinstain set up on my behalf. Though I am curious if it would be possible?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv
    lolcashcow wrote: »
    Hi Cariboo,

    You did mention that before. Sorry I was just so happy riding the Wattage Train I forgot about that little detail. Then I would have to set up the 45 watt panel set individually... or would it be possible to have the 170w with its on CC and the 45w with its own CC but connect both panels to a single battery? I think that thought is border line frankeinstain set up on my behalf. Though I am curious if it would be possible?

    You can have panels on separate controllers connected to the same battery bank. It's done quite often. The success of it is a matter of how compatible the controllers are; i.e. can they both be set for the same charging parameters. The closer they are to each other the better it works.
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    You can have panels on separate controllers connected to the same battery bank. It's done quite often. The success of it is a matter of how compatible the controllers are; i.e. can they both be set for the same charging parameters. The closer they are to each other the better it works.

    Greatness! That is good news :). I inspected the solar panel closely at the back and found some scratching. I took a picture and I uploaded it. Will these cause any performance issues? This caused an interesting turn of events. My friend said that he can give me a panel that is the exact same as this one to go with the one I currently have. Same maker/wattage/everything. So 170w*2 or he can just replace it with a 240w panel from a canadian maker. I believe he said canadian solar and gave me some measurements. After a google search I found this one http://www.civicsolar.com/product/canadian-solar-cs6p-245p-245w-poly-slvwht-solar-panel it could potentially be that panel. Advice?

    The Scratches
    http://i.imgur.com/WiN1srQ.jpg

    Close up
    http://i.imgur.com/Iu0YGIo.jpg

    Another area with indentation? or crack?
    http://i.imgur.com/cEHgrXS.jpg


    Should I be adding electric tape to protect these areas from the elements or other forms of repair to the panel? or will this destroy the panel and make it unusable?
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    That does not look good... You don't want any water/humidity to get to the cells.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv

    Agree with Bill. For experimenting with at the price of free, okay. They make stuff (not electrical tape) to dope panel backs with that could seal it against future intrusion, but what has happened already? You don't know.

    For a permanent install you intend to rely on, pass. Sometimes even when the bargain is free it isn't a bargain.

    The 245 Watt Canadian Solar panel (page won't load for me) will no doubt have a Vmp around 30, so there's that issue of matching panel Voltage to system Voltage again. MPPT controller, or let the Watts slide.
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv

    Hi guys,

    The scratch was likely caused during transfer of the panel on my end.... Can you advice me on what the material is called and the difficulty to apply/seal/repair? I've kept the panel inside the RV with out any further damage. Is it that oxygen alone could destroy the whole panel already?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv

    I can't find the name of the stuff actually used to dope panels, but have found references to people 'fixing' them with exterior-grade silicon sealant.

    The problem is that a bit of moisture can get inside and start the materials corroding. Connections between cells fail = no more power. If it's been kept dry it should not be an issue. But any sort of repair out in the weather is likely to be the first spot to fail.
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    If you do use RTV... The the stuff called Silicon II (2) or "Neutral Cure" type.

    The standard RTV uses acetic acid (vinegar) to cure and can be more corrosive.

    Standard crystalline panels are not too badly affected by oxygen--Just humidity/water.

    Thin Film panels, on the other hand, react very badly if just oxygen (air) gets into the panel.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv

    Hi Guys,

    Thank you very much for the input. I did a google search and found this from homedepot:

    http://www.homedepot.com/p/GE-Silicone-II-2-8-oz-Clear-Window-and-Door-Caulk-GE500-3TG/100179996

    Would this be what I am looking for?

    I also found

    http://www.homedepot.com/p/GE-Supreme-9-oz-White-Window-and-Door-Caulk-M90015-30-12C/202499233

    Is this the regular silicon.. 1? type with vinegar?

    Another question:

    Cariboo said that For a permanent install I should pass because Sometimes even when the bargain is free it isn't a bargain. Is this because there might be a high risk of the panel frying the CC, Battery, and Inverter?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv

    The first product linked says "Silicone II" so that should be the right product.

    The panel won't fry anything if it corrodes, it will just drop dead (low or no output). As a result you may one day find the battery has done likewise.
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    First is Silicone II, second is not:

    http://www.caulkyourhome.com/frequently-asked-questions.php
    How long will caulk release an odor?
    Caulk releases an odor during its cure cycle. Most of this process occurs during the first 24 hours after the product is applied. GE Silicone II* caulk is a neutral cure caulk and does not have the vinegar-type odor that is associated with acetoxy cure caulks like GE Silicone I* and most other silicone caulks.

    List of Silicone II products from GE:

    http://www.caulkyourhome.com/pdfs/GESiliconeProductGuideSheet2013.pdf

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    The first product linked says "Silicone II" so that should be the right product.

    The panel won't fry anything if it corrodes, it will just drop dead (low or no output). As a result you may one day find the battery has done likewise.

    Hi Cariboo,

    Okay, I have kept the panel inside the RV, so I feel that there should still be some hope for it. When doing the repair should I only make one layer with the Silicon II or multiple for better protection? Would you say that once the silicon sealant is applied it will not allow any moisture to enter? I think if the panel can last for 1 year I will be quite happy :)
    BB. wrote: »



    Hi BB,

    Thank you for the link I will read the FAQ, but do you think a single layer, or multiple layers would be best?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv
    lolcashcow wrote: »
    Hi Cariboo,

    Okay, I have kept the panel inside the RV, so I feel that there should still be some hope for it. When doing the repair should I only make one layer with the Silicon II or multiple for better protection? Would you say that once the silicon sealant is applied it will not allow any moisture to enter? I think if the panel can last for 1 year I will be quite happy :)

    Well the original coating thickness is measured in mils so I wouldn't be too overly-enthusiastic and pile it on thick. Once on it should keep the moisture out providing no further damage is incurred. How long it will last is anybody's guess.
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    After you put a layer of silicone on the cuts--(not too thick), let them harden and then find something you can glue (again with silicone) to the back of the panels to give you a little more protection).

    One of the reasons that temporary panel installations are a pain--They are easy to tear the backs and/or shatter the glass (usually tempered glass).

    Others are panels are easy to blow over in high winds, easy to steal, and forget to unplug when driving away, etc.

    The panels, if they fail, will not fry your batteries, they will typically simply lose output voltage and/or current. In theory, if you had panels in series, you could get series current through high resistance points causing overheat/potential fire--But that is probably not a big issue in this case (however, why we recommend fusing parallel strings--Just in case).

    Just to give you an idea of what badly built/designed (i.e., illegal) panels can do:

    http://forum.solar-electric.com/showthread.php?4524-Panel-Fire-Question

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    BB. wrote: »
    After you put a layer of silicone on the cuts--(not too thick), let them harden and then find something you can glue (again with silicone) to the back of the panels to give you a little more protection).

    One of the reasons that temporary panel installations are a pain--They are easy to tear the backs and/or shatter the glass (usually tempered glass).

    Others are panels are easy to blow over in high winds, easy to steal, and forget to unplug when driving away, etc.

    The panels, if they fail, will not fry your batteries, they will typically simply lose output voltage and/or current. In theory, if you had panels in series, you could get series current through high resistance points causing overheat/potential fire--But that is probably not a big issue in this case (however, why we recommend fusing parallel strings--Just in case).

    Just to give you an idea of what badly built/designed (i.e., illegal) panels can do:

    http://forum.solar-electric.com/showthread.php?4524-Panel-Fire-Question

    -Bill

    Hi BB,

    What do you suggest could be used as additional protection? I would guess something that is also water proof to start is a good idea? About how big should this additional protection be? Would I be looking into something that can cover the whole back of the panel or just the are that was damaged?
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    Could be anything light weight. Just something to prevent sharp corners from cutting in to the backing.

    Corrigated plastic, strips of wood, etc... Something sort of water resistant to avoid handling damage.

    If you permanently mount, you would not need any additional backing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    BB. wrote: »
    Could be anything light weight. Just something to prevent sharp corners from cutting in to the backing.

    Corrigated plastic, strips of wood, etc... Something sort of water resistant to avoid handling damage.

    If you permanently mount, you would not need any additional backing.

    -Bill

    Hi BB,

    Okay I did the repairs with Silicon 2. I will look into adding some strips of wood as additional protection. Out of curiosity would the Canadian Solar 245w Panel work with the morning star CC?

    http://www.solar-electric.com/mosumpsochco.html
    http://www.affordable-solar.com/store/discontinued-unavailable-solar-panels/Canadian-Solar-CS6P-245P-245W-Solar-Panel-STD-Frame
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    Yes if 12 volt battery bank.

    No if 24 volt battery bank (Vmp is only 30 volts, need ~35-40 volts minimum for charging a 24 volt battery bank, and two 30 volt panels in series is to high of Voc for the MS 15 amp MPPT controller).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv
    BB. wrote: »
    Yes if 12 volt battery bank.

    No if 24 volt battery bank (Vmp is only 30 volts, need ~35-40 volts minimum for charging a 24 volt battery bank, and two 30 volt panels in series is to high of Voc for the MS 15 amp MPPT controller).

    -Bill

    Okay thanks BB. I meant to say before that I will look into adding more protection to the back of the panel. It came out the wrong way when I typed it.

    Out of curiosity would it be best to stick with the Canadian panel that is 245w over getting the second 170w panel? My guess is that it will be harder to set up the panels if there are two instead of a single panel?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv
    lolcashcow wrote: »
    Okay thanks BB. I meant to say before that I will look into adding more protection to the back of the panel. It came out the wrong way when I typed it.

    Out of curiosity would it be best to stick with the Canadian panel that is 245w over getting the second 170w panel? My guess is that it will be harder to set up the panels if there are two instead of a single panel?

    No, go with the two 170 Watt panels with the 'real' Vmp for a 24 Volt system. The only difficulty is that you have to connect them in parallel. There's more than one way to do this, depending on which connectors are on them (MC4 or the older MC3).
  • lolcashcowlolcashcow Solar Expert Posts: 118 ✭✭
    Re: Solar Pannel for an rv

    Hi Guys,

    Out of curiosity I want to spread a thin layer of silicon 2 over the back of the panel just to make sure it is well protected. Is this a safe thing to do? While putting on the silicon 2 I found some tiny scrapes that I covered. Just to make sure though I feel that adding a thin layer all along the back would be the best idea. I just want to know it won't destroy the panel.... Advice?

    Sorry guys!
  • BB.BB. Super Moderators, Administrators Posts: 29,318 admin
    Re: Solar Pannel for an rv

    You won't destroy the panel--You will just get a goopy mess on the back with whatever local fauna and flora happens to be around that day to stick on the back.

    I think it would be better just to run your had (and/or a flashlight held at a sharp angle to the surface) and seal any possible nicks you find.

    Trying to spread it all over the panel and get a good seal everywhere is probably going to be difficult, and could be pretty costly with several tubes of silicone.

    My 2 cents--Not sure if it is right or wrong.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Pannel for an rv

    If you do spread it all over use a plastic spatula and a light touch. You don't want to run the risk of gouging it somewhere else.
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