RV 400 to 450 watt PV configuration questions

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  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    Re: RV 400 to 450 watt PV configuration questions
    BrokerDon wrote: »
    Thanks for the GoSolar website info. Great stuff!

    Sorry to for the NEEBIE question but what does "GT scale" mean?

    "Grid Tied"

    The Renogy panels have been advertising "Grid Tied" Systems for their panels on ebay and Amazon. For a DIY type of person the renogy's are cool, however they are too new in the market place for me as a professional to use them as a grid tied application. I've bought a few and the level of glass and frame isn't quite at the level it should be for myself as a contractor to back it for 10 year labor satisfaction warranty, mostly because they disclose 5 year craftsmanship, which in order to receive the federal tax incentive a true tier 1 PV panel comes with a 25 year performance/10 year craftsmanship warranty.

    Since by law I have to labor warranty for 10 years, I in no way can install a 5 year craftsmanship product. On the other hand both the sunpower, and the Solar world I suggested come with 10 year craftsmanship/labor warranty. Sunpower though you have to be a certified installer in order to get the warranty by sunpower if something becomes defective

    Even the racking systems have to be 10 year minimum warranty (I.E) Iron Ridge, Unirac, QuickMount, etc.

    So when I say GT scale, for me it means it does not pass go from a professional standard standpoint, but for the DIY'er its an application that works.
  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions
    "Grid Tied"

    The Renogy panels have been advertising "Grid Tied" Systems for their panels on ebay and Amazon. For a DIY type of person the renogy's are cool, however they are too new in the market place for me as a professional to use them as a grid tied application. I've bought a few and the level of glass and frame isn't quite at the level it should be for myself as a contractor to back it for 10 year labor satisfaction warranty, mostly because they disclose 5 year craftsmanship, which in order to receive the federal tax incentive a true tier 1 PV panel comes with a 25 year performance/10 year craftsmanship warranty.

    Since by law I have to labor warranty for 10 years, I in no way can install a 5 year craftsmanship product. On the other hand both the SunPower, and the Solar World I suggested come with 10 year craftsmanship/labor warranty. Sunpower though you have to be a certified installer in order to get the warranty by sunpower if something becomes defective

    Even the racking systems have to be 10 year minimum warranty (I.E) Iron Ridge, Unirac, QuickMount, etc.

    So when I say GT scale, for me it means it does not pass go from a professional standard standpoint, but for the DIY'er its an application that works.

    Thanks for explaining GT means "Grid Tied". Learning the abbreviations and anachronisms of things is always helpful!

    Unless I'm misreading something, Renogy's 250W mono panel performance warranty is a linear 25 for performance and 10 years for material and workmanship: (COPIED AND PASTED FROM THEIR WEBSITE)

    Renogy modules’ performance is guaranteed within 25 years from the time of purchase according to the above chart.

    Besides, our warranty also includes:

    (1) 25 year transferrable power output warranty: 5 years/95%, 10 years/90%, 25 years/80%
    (2) 10 year material and workmanship warranty

    Note: 3.5% in the first year, thereafter 0.68% per year, ending with 80.18% in the 25th year after the Warranty Start Date

    http://renogy.com/wp-content/uploads/2014/04/200above-warranty.pdf

    ... so I'm guessing you're saying Renogy won't warranty YOUR installation labor as an installer if their panels have a material and workmanship warranty problem in the first 10 years. If so I see why as an installer why you'd only want to install panels that come with a 10 year craftsmanship/labor warranty. Definitely makes sense.
  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    Re: RV 400 to 450 watt PV configuration questions
    BrokerDon wrote: »
    Thanks for pointing that out! My error. Actually our 40A Renogy Tracer MPPT controller's 4-stages are at:

    Equalization: 14.8V
    Boost: 14.6V
    Float: 13.8V
    Boost Return: 13.2

    http://renogy.com/wp-content/uploads/2014/05/MPPT-40A-Controller-Manual.jpg

    So whats your opinion of the MPPT and its overall efficiency? I was in the process of buying a few of the tracer 1210 models (10amps) approximately 2 of them until I came across these 2 comments, the specs are identical to the 40amp version.
    This is only based on the 10 amp models so I would think that the 40amp would have greater intermitent RF?
    I saw that you are using it in 90* weather, have you been able to determine or monitor the charge efficiency? Also is there software for the RJ45? Some say that it isn't capable of monitoring, so does Renogy sell some sort of diagnostic monitoring for their tracer version?

    Attachment not found.Attachment not found.
  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    Re: RV 400 to 450 watt PV configuration questions
    BrokerDon wrote: »
    Unless I'm misreading something, Renogy's 250W mono panel performance warranty is a linear 25 for performance and 10 years for material and workmanship: (COPIED AND PASTED FROM THEIR WEBSITE)

    Renogy modules’ performance is guaranteed within 25 years from the time of purchase according to the above chart.

    Besides, our warranty also includes:

    (1) 25 year transferrable power output warranty: 5 years/95%, 10 years/90%, 25 years/80%
    (2) 10 year material and workmanship warranty

    Note: 3.5% in the first year, thereafter 0.68% per year, ending with 80.18% in the 25th year after the Warranty Start Date

    http://renogy.com/wp-content/uploads/2014/04/200above-warranty.pdf

    ... so I'm guessing you're saying Renogy won't warranty YOUR installation labor as an installer if their panels have a material and workmanship warranty problem in the first 10 years. If so I see why as an installer why you'd only want to install panels that come with a 10 year craftsmanship/labor warranty. Definitely makes sense.

    Well I believe thats all changed or atleast you have a golden panel. Last year I had a client that wanted 6kWh of the renogies but they didn't meet the criteria. I still surf ebay and see that there are some with the 5 year craftsmanship warranty.

    I don't like that note of depreciation of 3.5% for the first year. That throws a huge red flag and doesn't follow NREL standards that are submitted to the fed, for fed tax credit. NREL also tighten the standards on tier 1 panels not depreciating greater than .5% per year for the first 20 years. Your panel depreciates "rapidly" at .68%, so it doesn't meet fed or state standards, it may meet UL approved standards, but it doesn't meet anything else other than UL which makes it an off grid application panel, the California Public Utility Commission won't recognize the panel for grid use on the grid.

    Renogy Sells a variety of 32 different panel types on the market, 23 make the short list as of this year sld on ebay/Amazon. Here is the short list of the panels that meet the warranty. Your particular model although meeting "standards", does not meet californias CSI, or fed credit according to teh short list. Model:RNG-250D-BK The last reference to its serial identifier (D-BK) makes it ineligible according to FED/CSI standards. The RNG-250P, does meet the qualifications. So as a california contractor, I can't back it, or install under the CSI since I am a CSI contractor. I can only warranty what is on the short list and meets both fed and state requirements. Hope that makes more sense.

    Basically the Renogy warranty is worthless, if it goes to litigation if state and fed don't back it, its just a sales gimmick. Here is teh CSI website for your refrence of what you should or should not purchase according to NREL/FED/CSI standards. http://www.gosolarcalifornia.ca.gov/equipment/pv_modules.php
    Attachment not found.
    Grid tied panels are never defined by voltage, or amperage, or the differentiation between off grid and on grid. Grid Tied is defined by it's level of performance to withstand conditions exceeding 25years at minimal depriciation according to NREL and the FED, so that it is a worthy investment in energy for the PUC, and energy producer.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: RV 400 to 450 watt PV configuration questions
    So whats your opinion of the MPPT and its overall efficiency? I was in the process of buying a few of the tracer 1210 models (10amps) approximately 2 of them until I came across these 2 comments, the specs are identical to the 40amp version.
    This is only based on the 10 amp models so I would think that the 40amp would have greater intermittent RF?
    I saw that you are using it in 90* weather, have you been able to determine or monitor the charge efficiency? Also is there software for the RJ45? Some say that it isn't capable of monitoring, so does Renogy sell some sort of diagnostic monitoring for their tracer version?

    SP see the posts here by Technodave on the Tracers... http://midniteforum.com/index.php?action=search2
     
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  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions
    Well I believe thats all changed or atleast you have a golden panel. Last year I had a client that wanted 6kWh of the renogies but they didn't meet the criteria. I still surf ebay and see that there are some with the 5 year craftsmanship warranty.

    I don't like that note of depreciation of 3.5% for the first year. That throws a huge red flag and doesn't follow NREL standards that are submitted to the fed, for fed tax credit. NREL also tighten the standards on tier 1 panels not depreciating greater than .5% per year for the first 20 years. Your panel depreciates "rapidly" at .68%, so it doesn't meet fed or state standards, it may meet UL approved standards, but it doesn't meet anything else other than UL which makes it an off grid application panel, the California Public Utility Commission won't recognize the panel for grid use on the grid.

    Renogy Sells a variety of 32 different panel types on the market, 23 make the short list as of this year sld on ebay/Amazon. Here is the short list of the panels that meet the warranty. Your particular model although meeting "standards", does not meet californias CSI, or fed credit according to teh short list. Model:RNG-250D-BK The last reference to its serial identifier (D-BK) makes it ineligible according to FED/CSI standards. The RNG-250P, does meet the qualifications. So as a california contractor, I can't back it, or install under the CSI since I am a CSI contractor. I can only warranty what is on the short list and meets both fed and state requirements. Hope that makes more sense.

    Basically the Renogy warranty is worthless, if it goes to litigation if state and fed don't back it, its just a sales gimmick. Here is teh CSI website for your reference of what you should or should not purchase according to NREL/FED/CSI standards. http://www.gosolarcalifornia.ca.gov/equipment/pv_modules.php
    Attachment not found.
    Grid tied panels are never defined by voltage, or amperage, or the differentiation between off grid and on grid. Grid Tied is defined by it's level of performance to withstand conditions exceeding 25years at minimal depriciation according to NREL and the FED, so that it is a worthy investment in energy for the PUC, and energy producer.

    WOW I've learned more from your posts about solar panels and charge controllers in the past 2 days than I've known before. THANKS for sharing your knowledge... Wish I had known this before I bought my Renogy panel and Tracer charge controller but hey its recharging our dual 6V GC@ Premium batteries which was the whole idea, although surely not as efficiently as buying a more efficient Midnite Solar Kid MPPT controller and NREL/FED/CSI approved panels.

    What single NREL/FED/CSI approved solar panels would you recommend for our severely limited 72" x 42" unobstructed RV roof area that would provide at least a 25% wattage improvement over our current single Renogy RNG-250D-BK 250W mono panel? The only ones I've found so far are the SunPower 327 E-series and 335 / 345 X21 series solar panels... but will one of these panels work on our Negative Ground fiberglass roofed RV since supposedly the SunPower panels want a Positive Ground?
  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions

    MORE great info which I would have loved to have before I bought my 40A Tracer MPPT controller. Thanks!
  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    Re: RV 400 to 450 watt PV configuration questions
    BrokerDon wrote: »

    What single NREL/FED/CSI approved solar panels would you recommend for our severely limited 72" x 42" unobstructed RV roof area that would provide at least a 25% wattage improvement over our current single Renogy RNG-250D-BK 250W mono panel?

    The best panels for the price on the marker right now are the SUNIVA 275's, or the SolarWorld 275's, for under a $1 a watt and you will come to find out that the cost comparison between the Renogy VS the SUNIVA/SolarWorld, and to have a tier1 GT panel is a far superior product. If you really want high end like sunpower you could get an LG290 or 300 but then you are looking at sunpower pricing at $1.25 watt and higher.
    The problem with SunPower is the warranty, you have to have an authorized installer install them, so warranty is difficult to deal with. I use to work for sunpower many years ago during the times when cypress semi conductor owned them, now they are owned by the french, a company called TOTAL the worlds largest oil conglomerate.

    The sunpower panels are amazing only for the cells, which you come to find out back contact cells are "cheaper" to produce than standard ingot cells, so sunpower is just way over rated for the name.
    When I look at a product and it's entirety I look at everything from the glass, to the frame, to the cell composition, on the market to date Solar World I believe offers everything you want for the highest longevity and durability.
  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions

    Honestly I'm not sure how to evaluate the efficiency of of my Tracer 40A MPPT controller... and if it has intermittent RF.

    How could I measure efficiency and RF? I do have the Tracer MeTer MT-5 LCD display attached which is where from watching the Tracer's MeTer display on sunny mostly cloudless 90 degree SoCal summer days the Tracer is:

    _ receiving 34.6V from my Renogy 250W 36V mono panel [its rated at 8.32A Optimum Operating Current (Imp)] and

    _ outputting 11.1A at 13.2 to 14.6V
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: RV 400 to 450 watt PV configuration questions

    Are you having RFI/EMI interference problems with your Tracer? (TV, AM/FM radio, Satellite, HAM, etc.???).

    In general, most of the less expensive charge controllers are probably not tested for EMI compliance--But the larger MPPT type charge controllers will tend to have more "high power/high speed" digital components which makes EMI compliance testing/rating more important and more difficult.

    Efficiency of charge controllers... For a PWM controller, it is simply the battery voltage divided by the "potiential" Vmp voltage of the array. To get closer, you also need to subtract the operating losses of the electronics--Which tend to be very small for the "simple" PWM charge controllers (not much power needed to run the controller itself).

    Vbatt/Vmp = 14.0 volts charging / 17.6 volts array = 0.80 = 80% "efficiency"

    Notice that these voltages and efficiencies are variable... On a hot day, solar panels can easily have 10% or even as high as 20% reduction in Vmp--And battery charging voltage can be near 12 volts when the battery is heavily discharged/under load, to as high as 14.8 or more volts as the battery enters the "absorb" (constant voltage) charging stage:

    14.8 volts absorb charging / 15.84 volts Vmp-hot = 0.93 = 93% efficiency for a PWM in "typical" application (ignoring "Tare"/operational losses)

    With a MPPT charge controller, it gets a bit more complex. If you have Vmp~18 volt panels and a 12 volt battery bank in a moderately warm climate with short wire runs from array to charge controller--There is not much reason to spend a lot of extra money for an MPPT charge controller (in smaller systems).

    Basically, the MPPT controller has more operational losses (more digital electronics and switching power supply circuits)--So just "turning on" takes more energy to run.

    Yes, the MPPT is an efficient "down converter" that can take "high voltage/low current" and down convert to "low voltage/high current" to run the battery bank. But, if you assume that the controller is ~95% efficient and that solar panels output ~81% of their "marketing" Vmp numbers in a typical warm climate, the overall efficiency of an MPPT charge controller is something like:

    0.95 * 0.81 = 0.77 = 77% overall system efficiency

    Which is pretty close to a "typical" PWM efficiency of ~80%

    If you have sub freezing weather and a "warm battery bank", yes, you can get another 10-15% or so more power from a MPPT charge controller vs a PWM controller in winter--But, you could also get a 10% larger array for the same price or less + PWM controller.

    Also, there are other issues with MPPT controllers--Some have better MPPT tracking algorithms and may give you a few percent more power than a different/cheaper/older brand or model of MPPT controller. And some MPPT controllers even have an internal Webserver for Internet connectivity (which takes more power to run).

    In the end, I would not fixate on efficiency for charge controllers... Without laboratory grade equipment and test conditions--It is very hard to get power (wattage) numbers that are more accurate than 10% of the "true" value (and even the lab gear does not "exactly" agree either).

    So, step back and look at your needs. PWM controllers tend to be a bit more cost effective in smaller off grid applications with 400 Watt or smaller arrays.

    For larger applications (say 800 Watts or larger arrays), MPPT controllers can be more cost efficient (pay more for the controller but pay less for >200 Watt GT type solar panels). And besides better networking/charging functionality and other "bells and whistles", MPPT controllers can also be very helpful when the wire runs from the array to the battery bank are more than a few 10's of feet.

    On long wire runs, voltage drop becomes a major problem... And you need much heavier gauge wire from the array to the solar charge controller. Something like 6-9 AWG gauge heavier cable (instead of 12 AWG cable, you may need 6 or even 3 AWG cable with a PWM charge controller). Copper is expensive (and easy to steal).

    So--My suggestion is always to do a couple paper designs first. And see which design best meets your needs. If you are concerned that an extra 5% loss of efficiency is going to cause problems--Get a 5% larger solar array and battery bank. The incremental increase in cost is small.

    Note that for a the design engineer--Controller Efficiencies are a very important part of the design process. A 95% efficient controller will "waste" 2x more heat vs a 97.5% efficient charge controller. Will need larger heat sinks, larger/more fans, etc.

    Heat is the enemy of electronics... For every 10C (18F) increase in operating temperature, the life of the electronics is cut by 1/2... So I am not minimizing the importance of efficiency and cooling--But just don't obsese over it. A good quality charge controller (and company) should have addressed those issues for you. If you don't like fans (not my favorite component), you can find charge controllers that have large open aluminum heat sinks. If you need a compact installation with high power ratings, then a fan cooled unit may be in order. If you have lots of dust/water/bugs--Then maybe a sealed fan cooled unit is more your liking.

    There are lots of options out there.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions
    The best panels for the price on the marker right now are the SUNIVA 275's, or the SolarWorld 275's, for under a $1 a watt and you will come to find out that the cost comparison between the Renogy VS the SUNIVA/SolarWorld, and to have a tier1 GT panel is a far superior product. If you really want high end like SunPower you could get an LG290 or 300 but then you are looking at SunPower pricing at $1.25 watt and higher.
    The problem with SunPower is the warranty, you have to have an authorized installer install them, so warranty is difficult to deal with. I use to work for SunPower many years ago during the times when cypress semi conductor owned them, now they are owned by the french, a company called TOTAL the worlds largest oil conglomerate.

    The SunPower panels are amazing only for the cells, which you come to find out back contact cells are "cheaper" to produce than standard ingot cells, so SunPower is just way over rated for the name.

    When I look at a product and it's entirety I look at everything from the glass, to the frame, to the cell composition, on the market to date Solar World I believe offers everything you want for the highest longevity and durability.

    Thanks for the panel recommendations. What panels >= 325W would you recommend that fit into our limited 42"x72" RV roof space? The panels > 300W I've seen (except SunPower) are 72 cell and 78" wide (too wide for our roof).

    If I was able to find SunPower 327 E-series or 335 / 345 X21 series solar panels what about their Positive Ground issue?
  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    Re: RV 400 to 450 watt PV configuration questions
    BrokerDon wrote: »
    Thanks for the panel recommendations. What panels >= 325W would you recommend that fit into our limited 42"x72" RV roof space? The panels > 300W I've seen (except SunPower) are 72 cell and 78" wide (too wide for our roof).

    If I was able to find SunPower 327 E-series or 335 / 345 X21 series solar panels what about their Positive Ground issue?
    For the price per watt I don't have any recommendations. Industry standard is not to exceed $1 per watt. High end panels like sun power, Panasonic, LG sell to what is a NICHE market place where the demand is absolutely needed.
    For your size and the demand you require it is not a necessity.
    panels with the higher conversion rate work for grid systems where at least there is a payout incentive by the utility company. Since there isn't any type of pay out or return for off grid anything over the $1 per watt thresh hold for panels is more of a depriciative deficit since the minor increase in energy for conversion rate isn't significantly yielding deficits against peakurts law.
  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions
    BB. wrote: »
    Are you having RFI/EMI interference problems with your Tracer? (TV, AM/FM radio, Satellite, HAM, etc.???).

    In general, most of the less expensive charge controllers are probably not tested for EMI compliance--But the larger MPPT type charge controllers will tend to have more "high power/high speed" digital components which makes EMI compliance testing/rating more important and more difficult.

    Efficiency of charge controllers... For a PWM controller, it is simply the battery voltage divided by the "potiential" Vmp voltage of the array. To get closer, you also need to subtract the operating losses of the electronics--Which tend to be very small for the "simple" PWM charge controllers (not much power needed to run the controller itself).

    Vbatt/Vmp = 14.0 volts charging / 17.6 volts array = 0.80 = 80% "efficiency"

    Notice that these voltages and efficiencies are variable... On a hot day, solar panels can easily have 10% or even as high as 20% reduction in Vmp--And battery charging voltage can be near 12 volts when the battery is heavily discharged/under load, to as high as 14.8 or more volts as the battery enters the "absorb" (constant voltage) charging stage:

    14.8 volts absorb charging / 15.84 volts Vmp-hot = 0.93 = 93% efficiency for a PWM in "typical" application (ignoring "Tare"/operational losses)

    With a MPPT charge controller, it gets a bit more complex. If you have Vmp~18 volt panels and a 12 volt battery bank in a moderately warm climate with short wire runs from array to charge controller--There is not much reason to spend a lot of extra money for an MPPT charge controller (in smaller systems).

    Basically, the MPPT controller has more operational losses (more digital electronics and switching power supply circuits)--So just "turning on" takes more energy to run.

    Yes, the MPPT is an efficient "down converter" that can take "high voltage/low current" and down convert to "low voltage/high current" to run the battery bank. But, if you assume that the controller is ~95% efficient and that solar panels output ~81% of their "marketing" Vmp numbers in a typical warm climate, the overall efficiency of an MPPT charge controller is something like:

    0.95 * 0.81 = 0.77 = 77% overall system efficiency

    Which is pretty close to a "typical" PWM efficiency of ~80%

    If you have sub freezing weather and a "warm battery bank", yes, you can get another 10-15% or so more power from a MPPT charge controller vs a PWM controller in winter--But, you could also get a 10% larger array for the same price or less + PWM controller.

    Also, there are other issues with MPPT controllers--Some have better MPPT tracking algorithms and may give you a few percent more power than a different/cheaper/older brand or model of MPPT controller. And some MPPT controllers even have an internal Webserver for Internet connectivity (which takes more power to run).

    In the end, I would not fixate on efficiency for charge controllers... Without laboratory grade equipment and test conditions--It is very hard to get power (wattage) numbers that are more accurate than 10% of the "true" value (and even the lab gear does not "exactly" agree either).

    So, step back and look at your needs. PWM controllers tend to be a bit more cost effective in smaller off grid applications with 400 Watt or smaller arrays.

    For larger applications (say 800 Watts or larger arrays), MPPT controllers can be more cost efficient (pay more for the controller but pay less for >200 Watt GT type solar panels). And besides better networking/charging functionality and other "bells and whistles", MPPT controllers can also be very helpful when the wire runs from the array to the battery bank are more than a few 10's of feet.

    On long wire runs, voltage drop becomes a major problem... And you need much heavier gauge wire from the array to the solar charge controller. Something like 6-9 AWG gauge heavier cable (instead of 12 AWG cable, you may need 6 or even 3 AWG cable with a PWM charge controller). Copper is expensive (and easy to steal).

    So--My suggestion is always to do a couple paper designs first. And see which design best meets your needs. If you are concerned that an extra 5% loss of efficiency is going to cause problems--Get a 5% larger solar array and battery bank. The incremental increase in cost is small.

    Note that for a the design engineer--Controller Efficiencies are a very important part of the design process. A 95% efficient controller will "waste" 2x more heat vs a 97.5% efficient charge controller. Will need larger heat sinks, larger/more fans, etc.

    Heat is the enemy of electronics... For every 10C (18F) increase in operating temperature, the life of the electronics is cut by 1/2... So I am not minimizing the importance of efficiency and cooling--But just don't obsese over it. A good quality charge controller (and company) should have addressed those issues for you. If you don't like fans (not my favorite component), you can find charge controllers that have large open aluminum heat sinks. If you need a compact installation with high power ratings, then a fan cooled unit may be in order. If you have lots of dust/water/bugs--Then maybe a sealed fan cooled unit is more your liking.

    There are lots of options out there.

    -Bill

    GREAT info... THANKS!

    So far we haven't noticed any RFI/EMI interference problems with our Tracer (22" Jensen HDTV, AM/FM radio, Sirius satellite radio, handheld FRS radios, iPhones, wireless weather station, etc.) but I'll pay more attention now that I know the Tracer could be a source.
  • BrokerDon
    BrokerDon Solar Expert Posts: 36 ✭✭
    Re: RV 400 to 450 watt PV configuration questions
    For the price per watt I don't have any recommendations. Industry standard is not to exceed $1 per watt. High end panels like sun power, Panasonic, LG sell to what is a NICHE market place where the demand is absolutely needed.
    For your size and the demand you require it is not a necessity.
    Panels with the higher conversion rate work for grid systems where at least there is a payout incentive by the utility company. Since there isn't any type of pay out or return for off grid anything over the $1 per watt thresh hold for panels is more of a depreciative deficit since the minor increase in energy for conversion rate isn't significantly yielding deficits against peakurts law.

    EXCELLENT explanation of PV panel economics being relational to conversion rates for grid tied but not off grid systems. Explains a lot!