Interfacing solar sys to RV?

K4KMG
K4KMG Solar Expert Posts: 50 ✭✭
in Off Grid Solar & Battery Systems #1
My camper is permanently situated, as is the solar setup. Camper is used on weekends only. Camper has the typical rv 30a hookup on the side. Can I just hardwire from my inverter to the camper using the typical 30a rv cord? What effect does the campers 'converter' have on this?

Thanks
Tom
· Share on Twitter

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Interfacing solar sys to RV?

    Can your solar power system stand the extra consumption? The power converters draw Watts (40-ish usually) even when nothing is running in the camper.

    Can your solar power system handle the current? The demand can be up to 30 Amps on that connection, and if that exceed the inverter's capacity (in combination with other loads) something has to give. Usually the inverter will suffer an overload fault. How will that affect your other use?

    If you're interested in just keeping the camper's battery up until used you might do better to bypass the converter and related loads and just run a line to a small battery tender directly on the battery. Or even give it its own maintenance panel.
    · Share on Twitter
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    #3
    Re: Interfacing solar sys to RV?

    Thanks.

    System:

    4x220w panels
    Vmp 29.5V
    Imp 7.46a
    Voc 35.4V
    Isc 8.36a

    Rogue 3048 30a cc

    Prosine 1800 inverter

    4 6v Trojan T105's (series)

    AC on the panel is on breakers and the dc is all your typical blade fuses.

    All lighting has been converted to LED's. If I unhook the camper batt, the converter wont expend energy trying charge it?

    Usage varies, but during the day, the item that gets used the most, at least in the summer is a box fan on the deck. (85w .67a)
    Small TV/DVR in the evening at 60w .60a.
    750w Microwave a few minutes both days.
    1150w 9.5a toaster oven 2 min each day.
    Occasional phone/tablet chargers.
    12v water pump. specs unknown. (dishes, shower, toilet)

    The solar sys is not really needed as I have plenty of generators, but since I have the solar equip, I might as well use it for what I can get out of it. Would prefer not to have to rewire the camper as it's relatively new.

    After writing the above, it does seem that a separate panel for the solar would probably be a good idea, although simply plugging into the camper is a whole hell of a lot easier! :)
    · Share on Twitter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Interfacing solar sys to RV?

    Well an 1800 Watt Prosine isn't going to supply 30 Amps. 15 maybe.

    It sounds like you want to use this camper while stationary? Because the converter is necessary not only for charging the battery but also for running any 12 VDC loads. That's basically what it does; takes over supplying the 12 VDC and puts power back in the battery. No point in disconnecting the battery if that is the case; the converter will suck up power just the same, only without the battery-charging load. They are rather inefficient, frankly.

    If you want your inverter to supply the camper AC loads directly you will have to unhook and bypass the camper's converter. This is important to do correctly as quite a few people have got confused in the wiring and ended up with the inverter powering the converter which charged the batteries that were running the inverter. The result is a 'perpetual motion loop' that does nothing but drain the batteries in an endless cycle of running inverter and converter to no purpose!
    · Share on Twitter
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    #5
    Re: Interfacing solar sys to RV?

    Yes, stationary. The campers battery is kept at home on a charger during the week at it usually has enough juice to run the 12v stuff for the 2 1/2 days I'm at my camp.
    So, the best utilization of the solar would be to isolate the ac and just run ac stuff?

    How about some sort of transfer switch to transfer power between solar sys and converter sys? I could keep the original camper system intact and just switch from the converter to solar as needed/wanted.
    · Share on Twitter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Interfacing solar sys to RV?
    K4KMG wrote: »
    Yes, stationary. The campers battery is kept at home on a charger during the week at it usually has enough juice to run the 12v stuff for the 2 1/2 days I'm at my camp.
    So, the best utilization of the solar would be to isolate the ac and just run ac stuff?

    How about some sort of transfer switch to transfer power between solar sys and converter sys? I could keep the original camper system intact and just switch from the converter to solar as needed/wanted.

    Yes, that's a good plan: transfer switch to take loads from converter to inverter. Minimum amount of fuss, maximum safe wiring, no converter chewing up power needlessly. The exact installation will be specific to your camper unit and how comfortable you are with making changes. At the very least you would have a disconnect for the AC to the converter. There may already be one (breaker on input) and all you have to remember to do is switch it off when powering from the inverter.
    · Share on Twitter
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    #7
    Re: Interfacing solar sys to RV?

    Thanks. Seems like the best plan. Least amount of disruption to the existing setup.

    I'm very comfortable making these changes although, the 'remembering' part might be an issue! Getting old is sooo much fun!
    · Share on Twitter
  • Mustang65
    Mustang65 Solar Expert Posts: 42 ✭✭
    #8
    Re: Interfacing solar sys to RV?

    This may work for you...

    I believe you want to do what I did to my RV. I wired 120VAC output from my inverter (located in front storage area by batteries) to the rear storage area where my shore power cable is stored. I installed a RV 30 amp receptacle (Lowes) that is wired into the RV's house AC wiring. When at a campground that has shore power I plug the RV shore power cable into the campgrounds 120VAC outlet, if I am dry-camping I plug the RV shore power cable into the RV 30Amp receptacle that I mounted in the storage compartment and is wired into the inverter.
    I turn on the inverter and have 120VAC to all RV outlets. Here are a few pictures.

    So that the RV's charge controller does not drain the batteries while running off the inverter power, I re-wired the RV's charge controller to its own AC breaker in the panel. Since adding solar to the RV, I have yet to turn on the RV's battery controller (about 18 months so far). The solar panel has supplied 100% of the batteries needs and our needs while dry camping. I will be adding an additional 250watt Solar panel and 2 more batteries, as we will be doing more dry camping next year.

    We have a sign that hangs over the AC thermostat that says, "Do not turn AC on", just as a final reminder while using the inverter. I have one spare breaker in the box, so I may wire the AC to its own breaker and just turn that on/off as needed.

    Works for us...
    Don



    2013 Jayco Eagle 284BHS
    250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
    1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
    2 - AirSight Wireless IP Cameras (used as rear view cameras)
    EnGenius WI-FI extender, D-Link wireless (n) modem
    MagicJack Internet Phone
    2012 Ford F150XLT, EcoBoost w/3.73
    157" Wheel base, HD Towing Package

    Attachment not found.
    Attachment not found.
    · Share on Twitter
  • K4KMG
    K4KMG Solar Expert Posts: 50 ✭✭
    #9
    Re: Interfacing solar sys to RV?

    Excellent! Thanks.
    · Share on Twitter
  • Mustang65
    Mustang65 Solar Expert Posts: 42 ✭✭
    #10
    Re: Interfacing solar sys to RV?

    One thing to note regarding my wiring diagram.. the Solar panel's negative lead is not grounded, it is run to the MPPT Charge Controller. Will correct that once I get back home.

    Don
    · Share on Twitter
  • ZoNiE
    ZoNiE Solar Expert Posts: 100 ✭✭
    #11
    Re: Interfacing solar sys to RV?

    I plan to do something similar with mine, but I want to wire a 700-1000W inverter to a SPDT (3 way) light switch rated at 20A. One pole will be to the inverter through it's own breaker, one to the main AC bus through the breaker for the receptacles only. The common will be to the outlet circuit. The original breaker will protect the circuit when in AC bus mode (plugged into shore power or genset) and the Inverter's output breaker will protect the circuit when switched to inverter. The nice thing about this method is that a simple light switch under an outlet cover on the wall will control the whole thing manually with no losses or relay to burn out by pulling in on shore power 24/7.

    The inverter will only power the outlets, and the Microwave and 2 way refrigerator will be moved to a separate circuit so it doesn't switch to 110V when it detects AC. If I need the Microwave or the Air conditioning, I have the Generator for that.

    The switch should be good for this due to it being a 20A industrial grade part and the most we ever plug into the outlets are our laptops, the TV, and an occasional power tool.

    I think this is a simple solution that hasn't been done by anyone that I can tell. The inverter's breaker will be under the same outlet box cover with a remote switch and power LED for the inverter so It can all be controlled from near the RV's power center with the inverter in the front storage compartment close to the 2 GC2's.
    · Share on Twitter

Categories