RV Solar System / Charge Controller

tr0y
tr0y Solar Expert Posts: 99 ✭✭✭
in Off Grid Solar & Battery Systems #1
Hi All -

With your help I have now been living off the grid for over a year in my solar powered house, now it it time to outfit the RV.

My RV is 12v based, interior lights, water pumps, audio and video etc, I also have a 120v system for the micro, fridge, and some outlets for other 120v stuff.

I currently have a Xantrex / Trace DR1512 inverter charger, four 400 AH 6v AGM lifeline batteries, and I charge from either shore power or a quiet Honda 2000 generator. I have come into four 100 watt, 12v panels that I am going to mount on the roof.

My question is what do you all think would be the best way to wire panels and what to do about a charge controller ?

Should I wire the panels as a 12v system get a cheap charge controller and call it a day ? or do I wire them up as 48v get a nice MPPT charge controller and do it the same way my home is wired up ?

What route would be best ? and if it is going with a nice MPPT charge controller, do you think the cost would be worth it vs less efficiency ? Am I going about this all wrong ?

We use the trailer a couple times a month for a couple of days at a time, not sure that the solar piece is really necessary but the panels were free.

Thanks
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: RV Solar System / Charge Controller

    Part of it depends on the actual Vmp of the "12 volt panels"... If they are between ~17-20w volts Vmp--then you can use either a PWM or MPPT type charge controller... If they are below or above that voltage range, then you probably want an MPPT.

    Roughly:
    • 400 watts / 17.6 volts = 22.9 amps
    So, you are looking at a 25-30 amp or so controller...

    At 400 amps and a short run from the panels to the charge controller/battery bank--either PWM or MPPT should work fine.

    If you RV in significantly hot or cold (below freezing weather)--The wider voltage range of an MPPT controller with two (or more depending on controller and panel Vmp) panels in series can be nice.

    You could also look at a (cheaper PWM controller without display) and put some of the savings towards a battery monitor (really nice for AGM batteries where you cannot measure specific gravity).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #3
    Re: RV Solar System / Charge Controller
    tr0y wrote: »
    .. or do I wire them up as 48v get a nice MPPT charge controller ...

    That's how I would do it.
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  • tr0y
    tr0y Solar Expert Posts: 99 ✭✭✭
    #4
    Re: RV Solar System / Charge Controller

    Thanks guys it sounds like the MPPT route is the way to go. The panels 17.x Vmp a Keocerya of some sort.

    I think I have a line on a pre-owned Outback MX60 for 200.00ish so I think I will do that.

    Next Question - I also think I need to put some better / bigger fuses in the positive cables, what would you suggest for RV use building a box with breakers just doesn't fit the space.

    Thanks Happy Christmas !
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  • vcallaway
    vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
    #5
    Re: RV Solar System / Charge Controller

    I'm using ANL fuses that are normally used for stereo installs. Most fuse holders will handle up to a 0 awg wire.
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #6
    Re: RV Solar System / Charge Controller

    These are great for small spaces. From Blue Sea. They attach right to the battery terminal.
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  • tr0y
    tr0y Solar Expert Posts: 99 ✭✭✭
    #7
    Re: RV Solar System / Charge Controller

    Thanks that little Stud fuse is cool. Would be perfect.
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