Choices for 2kw Solar on a RV



  • VicVic Solar Expert Posts: 3,026 ✭✭✭✭

    Too Tall,

    Just for quick comparison purposed,   here is the Classic +  page on our Sponsor's site:

    Regarding fan noise of Classics,  ambient environment temperatures have a very large effect on fan run-time and effectiveness,   as does CC output current and input voltage.

    If the CCs are in Conditioned space,   this is generally a good environment.

    To the extent that the bedroom in not often used during prime PV production and/or the higher ambient heat periods,  then, any fan noise should be less important.

       ...  need to tend to battery EQ,  more later,   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • TooTallTooTall Registered Users Posts: 7 ✭✭
    edited August 2017 #33

    BB. said:
    Of course, this all depends on where you will be camping (location) and if you will have an array that can be tilted depending on season (a 2,000 watt array is not small, making a tilt mount on an RV is not easy--plus it has to withstand the wind when going down the highway). And you may want to tilt the array flat if you are in areas of high wind when camping (big sail).

    In the far north, with poor weather (if coastal/marine layer camping) in winter--There just is not a lot of sun. And you need sun to make solar power (I would not even suggest looking at a wind turbine).

    A Honda eu2000i will give you about 3,600 Watt*Hours per gallon of gasoline (assuming a 400 watt load and 9 hours per gallon). Or about 2-4 days of equivalent sun per gallon of gasoline. Solar in winter to avoid fuel usage/costs--May be difficult to justify.

    Should I drop the idea of solar because I'm better off running a generator 2-3 months a year? 
  • BB.BB. Super Moderators, Administrators Posts: 30,939 admin
    I don't know.

    Have to look at your loads (ah / wh per day,  by season), where you will be camping, how long are dry camping (days or weeks at camp), seasons you will be camping,  etc.

    Batteries have less capacity when cold.  lithium ion batteries can be very nice for RV use, but most don't like operating below freezing.

    My aim is to size the battery bank (voltage and AH) to your loads/energy needs. Then design the solar+generator system to support your loads and keep the battery bank happy.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Marc KurthMarc Kurth Solar Expert Posts: 809 ✭✭✭✭
    edited August 2017 #35
    At the risk of being repetitive, system layout and sizing always starts with understanding load profiles along with customer expectations. There has been a lot of good hardware discussion so far.

    I always have more questions than answers. That's the nature of life.
  • bill von novakbill von novak Solar Expert Posts: 891 ✭✭✭✭
    TooTall said:

    Should I drop the idea of solar because I'm better off running a generator 2-3 months a year? 
    Solar and generator can definitely coexist.  A solar power system that can cover your needs in a sunny area with some conservation is still valuable; it reduces generator run time (and noise) and saves gas. If going with a 2kW system is going to be difficult (problems mounting/tilting array, wire gauges etc) reducing the array to something more manageable might make a lot of sense.
  • PhotowhitPhotowhit Solar Expert Posts: 5,323 ✭✭✭✭✭
    Vic said:
    Photowhit said:
    BB. said:
    Generally, the standard minimum/maximum  Vmp-array (standard name platevoltage) voltage for pwm charge controllers is

    12v...17.5/19 volts Vmp
    24v...35/38 Vmp
    48v...70/76 Vmp

    We have boB from Midnite here from time to time, I've book marked his recommendations for input for the Midnite classics on another computer. From my feeble mind;

    For MPPT to work properly you need @30% higher input than output, so a 48 volt system typically charging at 60 volts you would need @88 vmp input.


    This is what I had tried to note before.

    When the MN Parameters are Submitted in the MN Sizer,  there are two Notes at the foot of the Sizer results.  The second Note includes the following:
    "   ...    BUT you also have to be careful not to have the input voltage to low. Most all MPPT controllers will want to see a minimum of 130% of the actual high battery voltage. So if we have a 48v battery and it has an Equalize voltage if 62.3 volts than we would multiply that by 130% and we would need a minimum of 81 volts on the input on the hottest day of the year in order to have enough headroom for the MPPT to work   ...   "

    FWIW,   Vic

    My math is a bit wonky... Oddly enough I just can't add 18 to
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do
Sign In or Register to comment.