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van, full time in the PNW - am I at least on the right track?

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  • van, full time in the PNW - am I at least on the right track?

    Hi, everyone - new to solar, reading as much as I can but retaining is a whole other issue. I'm overwhelmed to say the least. Am I at least on the right track for a small system, full time van living in the PNW? Hoping to spend around $1500 (hahahahahahah). Thank you.

    My expected watt hours:

    Fridge/Freezer (guesstimate based on comparable systems) 500
    LED lights (8 lights x 3w x 5 hrs/day) 120
    Fan (6w x 24hrs/day) 144
    Phone chargers/laptop chargers nominal

    Total watts = 764/12v x 4 = 255Ah

    Am I doing this right so far?

    Eventually I want to add an inverter to my system. Did I do these calculations correctly? I followed the lead of one of the mods:

    Magic Bullet (900w / .8eff) 1125
    Insta Pot, a girl can dream (700w / .8eff) 875

    I'm thinking 300 watts solar and tapping into the alternator via an isolator.

    PLANNED PURCHASES

    Panels
    Grape Solar 180w panels x 2

    Charge Controller
    Bogart Engineering SC-2030 Charger <--30amps max
    *am I correct that I need a CC rated at least 23 amps? Vmpp on these panels is 19.67
    *is a PWM sufficient with my system?
    *I want one without a web interface

    Monitor
    Trimetric 2030-RV Battery Monitor

    Batteries
    Two 6v 225-255Ah Interstate FLM batteries wired in series

    Inverter
    I don't know which one yet. I do remember a mod here saying never to use more than 1000w in a 12v system.

    Battery Isolator
    Who knows. Haven't started researching yet.

  • #2
    Originally posted by Vanda View Post
    Am I at least on the right track for a small system, full time van living in the PNW? Hoping to spend around $1500 (hahahahahahah). Thank you.

    My expected watt hours:

    Fridge/Freezer (guesstimate based on comparable systems) 500
    LED lights (8 lights x 3w x 5 hrs/day) 120
    Fan (6w x 24hrs/day) 144
    Phone chargers/laptop chargers nominal

    Total watts = 764/12v x 4 = 255Ah

    Am I doing this right so far?
    So far so good. Typically you would want 5 day reserve, but you can get away with 4 days. .

    Originally posted by Vanda View Post
    Magic Bullet (900w / .8eff) 1125
    Insta Pot, a girl can dream (700w / .8eff) 875
    I have no clue what you are talking about. Is that some kind of ganja they sell at dispensaries in the PNW

    Originally posted by Vanda View Post
    I'm thinking 300 watts solar and tapping into the alternator via an isolator.
    OK

    PLANNED PURCHASES

    Panels
    Grape Solar 180w panels x 2

    Originally posted by Vanda View Post
    Charge Controller
    Bogart Engineering SC-2030 Charger <--30amps max
    *am I correct that I need a CC rated at least 23 amps? Vmpp on these panels is 19.67
    *is a PWM sufficient with my system?
    *I want one without a web interface
    Monitor
    Trimetric 2030-RV Battery Monitor
    OK now you are getting into trouble. Lets atrt with the controller and battery monitor. The controller is NOT PWM, it is MPPT which you want. With MPPT Output Current = Panel Wattage / Battery Voltage. 360 watts / 12 volts = 30 amps, so the controller is too small. Drop the Battery Monitor from your want list as it is useless other than it will tell you when your batteries are dead. Take the money saved and buy you a good 30 Amp Controller like Midnite Solar Kid.


    Originally posted by Vanda View Post
    Batteries
    Two 6v 225-255Ah Interstate FLM batteries wired in series
    Would not be my first choice, bu tOK for a Starter set because you will destroy even a better battery in 1 year time frame. So save your coins for a year while you learn how to operate and take care of your batteries and replace them in a year or so with Trojans or US Battery Gold Cart batteries.

    Originally posted by Vanda View Post
    Battery Isolator
    Who knows. Haven't started researching yet.
    Get this first before panels and controller. The Isolator is the real work horse and does all the work. the panels are just for show and tell and to empty your wallet of cash. If you drive an hour every day the panels essentially do nothing and can be eliminated all together.

    My suggestion in your circumstances, and lot less expensive.

    Pair of 6-volt Golf Cart Batteries of 200 to 250 AH like you intend.
    True Sine Wave Inverter something in the 300 to 600 watt range. Samlex, Xantrex, Cotex, and Go Power make good mobile inverters.
    Sure Power 50 to 70 Amp 2-port Electronic Battery Isolator. One port for the vehicle battery, and the other for House Battery.

    Optional Equipment

    Panel Wattage 150 to 200 watts, a single panel.
    Morning Star Sun Saver 15 amp MPPT
    MSEE, PE

    Comment


    • #3
      I have no clue what you are talking about. Is that some kind of ganja they sell at dispensaries in the PNW
      You know we've got the good stuff up here..

      Sunking - I don't think you guys allow the posting of links here, but when I google that controller the spec sheet says it is:

      -High efficiency charging at lower cost than MPPT chargers......Other type panels require a more expensive MPPT type charger for high efficiency.
      -Up to 30 amps maximum solar current

      So to me this looks like a PWM controller rated up to 30amps.

      What am I missing...?


      Would not be my first choice, bu tOK for a Starter set because you will destroy even a better battery in 1 year time frame. So save your coins for a year while you learn how to operate and take care of your batteries and replace them in a year or so with Trojans or US Battery Gold Cart batteries.
      Yes, I've read multiple places here to just get a starter set of batteries while I'm learning the ropes. Great advice, thank you. I'll most likely get the battery recommendation you gave me. I originally wanted the more expensive AGM batteries but after reading around this forum I see the fault in that (at least right off the bat).

      Comment


      • #4
        Also, why do I want MPPT vs PWM? I've been reading about the differences so I (kinda) know those. But why do YOU think I need one vs. the other?

        Comment


        • #5
          Originally posted by Vanda View Post

          You know we've got the good stuff up here..

          Sunking - I don't think you guys allow the posting of links here, but when I google that controller the spec sheet says it is:

          -High efficiency charging at lower cost than MPPT chargers......Other type panels require a more expensive MPPT type charger for high efficiency.
          -Up to 30 amps maximum solar current

          So to me this looks like a PWM controller rated up to 30amps.

          What am I missing...?
          Math and how panels, controllers and batteries work.

          PWM Output Current = Input Current
          MPPT Output Current = Panel Wattage / Battery Voltage

          So a 180 watt Grape solar panel Imp (current at maximum power) is 9.15 amps. So 9.15 amps input to the PWM Controller and 9.15 Amps on the output to the 12 volt battery.

          Power = Voltage x Amps.

          So 9.15 amps x 12 volt battery = 110 watts from your 180 watt solar panel using a PWM controller. Extremely poor efficiency.

          For a MPPT Controler output we have 180 watts / 12 volts = 15 amps and 15 amps x 12 volts = 180 watts. So whoever wrote what you read is smoking the good stuff and hallucinating and do not have a clue what they are talking about.

          So yes you can get a 30 Amp MPPT controller, but it will take 540 watts to push that much current. Or you can get a 30 amp MPPT Controller, save a ton of cash with only needing to buy 360 watts of panels.

          Resume Ganja smoking now.
          Last edited by Sunking; 04-20-2018, 04:56 PM.
          MSEE, PE

          Comment


          • #6
            You are in a bind with the controller. So, answer this question first. Will both panels be equally in the sun ?

            If you answer yes, you can wire in series and use MPPT controller.
            If you answer no, you must wire in parallel and seek a MPPT controller with low overhead requirements. 17V panels don't give the MPPT circuit much to downconvert with. It's a wild guess if it will work or not. If a MPPT controller cannot be found to function at 17V, then you need PWM, and kiss the extra power goodby..

            Skip the battery monitor, next to useless, Get an RV push-to test battery meter, about 20 bucks all you need, unless you PV charge controller is easily visible and has a meter on it.
            Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
            || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
            || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

            solar: http://tinyurl.com/LMR-Solar
            gen: http://tinyurl.com/LMR-Lister

            Comment

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