controllers

ws9876
ws9876 Solar Expert Posts: 448 ✭✭✭
in Caravan, Recreational Vehicle, and Marine Power Systems #1
it would be nice if a reputable solar company could make an mppt controller that takes 150v and can charge up 12-48 and sell it for
100$.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    ws9876 said:
    it would be nice if a reputable solar company could make an mppt controller that takes 150v and can charge up 12-48 and sell it for  100$.
    Well you posted this inn caravan, RV, Marine...

    So let's discuss why you would need a 150V mppt  on a RV?

    I would suggest about 1200 watts is the most array you would normally fit or need on an RV.  I say need because there isn't realistically enough room to run a system large enough to run an air conditioner as you would have to park the camper in the sun and there isn't enough insulation to run an Air conditioner with the sun exposure.

    ...and 1200 watts is enough to run a pretty wasteful person's needs, in terms of a fridge, TV, Computer.

    A 1200 watt system could be put on a 24 volt battery bank and a 40 amp MPPT charge controller such as a Renogy Rover at $100;

    https://www.amazon.com/Renogy-Rover-Amp-12V-24V/dp/B07DNVTJHD/ref=asc_df_B07DNVTJHD/

    It does have a 100 VDC  limit, but appears to be able to over panel to a effective level, Manual says;
    Rover 40 amp MPPT Manual; 
    PV Overcurrent
    The controller will limit the battery charging current to the maximum battery current rating. Therefore, an over-sized solar array will not operate at peak power
    It does also say;

    ws9876 said:
    Rover 40 Amp MPPT Manual
    Max. Solar Input Power
    "...24V @ 1040W"
    This is effectively the max you should expect out of a 1200 watt array.

    Shouldn't be hard to find 4 cheap 300 watt panels that you could use with this charge controller in a 2x2 configuration to output 40 amps to a 24 volt battery bank, without the need for a combiner box.

    It even gets pretty good reviews. Manual seems to think the BTS is included, but no mention of it;

    https://www.amazon.com/Renogy-Rover-Amp-12V-24V/dp/B07DNVTJHD/ref=asc_df_B07DNVTJHD/

    I would guess it's made by Y-solar who also makes the EPever/Tracer 40 amp Charge controller that has similar spec's;

    https://www.amazon.com/dp/B07KW5W49J/ref=sspa_dk_detail_5


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,101 ✭✭✭✭✭
    #3
    From EPever,


    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • PNW_Steve
    PNW_Steve Registered Users Posts: 79 ✭✭
    #4
    I must be extremely wasteful...... 

    I have 1800 watts of panels going on the roof and still expect to run the generator periodically. 


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  • ws9876
    ws9876 Solar Expert Posts: 448 ✭✭✭
    #5
    I wonder if you could get into the 75v 15 amp version and increase its amp rating...


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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #6
    ws9876 said:
    I wonder if you could get into the 75v 15 amp version and increase its amp rating...
    https://youtu.be/lg4_Kf9B0MI

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #7
    Not easily... If you think that a limitation is the heat generated inside the charge controller as an issue... Such as its internal resistance (heavier wire, larger Transistors, larger capacitors, larger inductors, etc. lower resistance).

    If, for example, you wanted to push 2x more current through the charge controller without changing its internal resistance:
    • Power = Current^2 * Resistance.... 2x current, 4x more heating (2^2 or 2 squared).
    So--To make a charge controller that will carry 2x more current without overheating, you need to reduce the internal resistance by a factor of 4...

    Or, if you are going to allow more heat to be generated, you need to have a 4x larger heatsink to keep the parts cool. Simply raising the operating temperature by 10C (18F), you reduce its operating life by 1/2 ... Raise temperature by 4x, then reduce life by (1/2 * 1/2=) 1/4 the operational life.

    And then for MPPT controller, there are the operational considerations... Internally, they have "pulse width" based energy transfer and control.... More or less, an amount of energy is transferred from the input to a large inductor. Then the switch is turned off, and the inductor dumps its stored energy to the output (battery bus) via a diode that supplies current for the transfer to the battery bus:

    https://en.wikipedia.org/wiki/Buck_converter

    This stuff is not trivial.

    Large/efficient inductors cost money (ideally copper wire or better, better inductors are are wrapped around a toroidal core/form). And power transistors + controlling electronics are not trivial. At least in the olden days, wrapping a toroid was a manual operation. They do have semi-automatic winding equpment now... But it can still require a human to operate:

    https://en.wikipedia.org/wiki/Toroidal_inductors_and_transformers
    https://www.youtube.com/watch?v=82PpCzM2CUg (toroid winder)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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