New Solar User

PeterPanel
PeterPanel Registered Users Posts: 2 ✭
in Solar Beginners Corner #1
Hello Geniuses!
I'm a new solar user and found a deal on some Schuco panels, $30usd each.  So I bought a few to see if they would be useful to me.  The ratings are as follows:

Pmpp 185Wp
Umpp 36.5V
Impp 5.09A
Uoc 44.8V
Isc 5.47A

I'm looking for guidance on stepping these down to 12V-15V and charging a bank of 12V deep cycle batteries.

I also have a number of questions on a scratch built system for use in my shed and yard lighting, nothing major just safe reliable and cost effective.

I have seen step down transformers with minimal circuitry so I might provide power to a charge controller and charge a 12V deep cycle.  I might also drive a power inverter for light 110V loads.

Topics I need help with include:  Circuit diagram, breaker placement, panel measurements, max volt/amp/watt. As well as mitigating the solar electrical supply so that I can support a 12V deep cycle battery bank.

I'm a beginner, but I have worked on and solved some difficult and complex situations in other technical and non-electrical situations.  I'm capable of understanding and learning but I lack the specific background and equipment exposure to build a solar powered system.

I'm hoping you can help. 

Thanks!

Peter
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Comments

  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    Welcome Peter!

    Solar is rarely cost effective.

    To do things most cost effectively, with the VMP (not Ump) panels, you can either look for am MPPT type charge controller which would down convert most of the wattage to the correct voltage to charge a 12 volt battery bank, and it would also control the charging. They aren't very cheap. They are rated on current output in general.

    Perhaps a better solution is going to a higher voltage AC 'all-in-one' charger inverter and send AC or convert back to DC for servicing loads. I say this because multiple strings of batteries are difficult to share charge and discharge cycles. In addition you would want all the batteries to be the same size and age...




    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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  • PeterPanel
    PeterPanel Registered Users Posts: 2 ✭
    #3
    Thank You Photowhit for your response.  I would like to keep these Ump panels.  What are the differences between the VMP and Ump?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,631 admin
    #4
    Confusion between letter "U" and letter "V"... In our normal terms, Vmp = Voltage maximum power. There is no "U" parameter (typo/font issue on panel labels?).

    The process is:
    • What is your daily energy usage (xx AH @ 12 volts, Watt*Hours, etc.). All year round, non-winter, etc. times?
    • Where (roughly will system be located) to figure out Hours of Sun per day by season
    • Figure out battery bank size (typically storage is 4x daily AH @ 12 volts per day is a good start)
    • 12 VDC or 120 VAC (DC or AC inverter)?
    • Backup power (genset or not--Basically more panels is less genset usage).
    • Full time off grid usage? Or only when the "sun shines" (not used during a week of bad weather, etc.)....
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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