How to step down from 60V so my 48V inverter will work

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  • Kipster
    Junior Member
    • Aug 2015
    • 3

    How to step down from 60V so my 48V inverter will work

    I have a set of solar panels that put out a nominal 60V. My inverter is rated at 48V with a disconnect at 60V. When I connect them together, the inverter gives an over-voltage error and dis-connects. Is there a simple way to bring the voltage down by several volts so the inverter will work?

    Sorry if this question has already been addressed. I searched and could not find it.

    Thanks!
  • sensij
    Solar Fanatic
    • Sep 2014
    • 5074

    #2
    Are you trying to run your inverter directly off the panels, or is there a battery in there somewhere?
    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

    Comment

    • Kipster
      Junior Member
      • Aug 2015
      • 3

      #3
      I would like to run the inverter directly from the panels.

      Comment

      • Wy_White_Wolf
        Solar Fanatic
        • Oct 2011
        • 1179

        #4
        What voltages is your charge controller set at? Or are you not running one?

        WWW

        Comment

        • Wy_White_Wolf
          Solar Fanatic
          • Oct 2011
          • 1179

          #5
          Originally posted by Kipster
          I would like to run the inverter directly from the panels.
          You've just found out why you can't.

          WWW

          Comment

          • Kipster
            Junior Member
            • Aug 2015
            • 3

            #6
            So even without a battery in the system, a charge controller is still required? I hope you'll pardon my ignorance, I'm just getting started so I'll likely ask some ignorant questions. Or do I just need to bite the bullet and add batteries to the system?

            Comment

            • SunEagle
              Super Moderator
              • Oct 2012
              • 15124

              #7
              Originally posted by Kipster
              So even without a battery in the system, a charge controller is still required? I hope you'll pardon my ignorance, I'm just getting started so I'll likely ask some ignorant questions. Or do I just need to bite the bullet and add batteries to the system?
              No. For your inverter to work you will need both a battery system and charge controller. Solar panels will not produce the correct amount of voltage for the inverter to run properly. That is why you need a battery.

              Comment

              • bcroe
                Solar Fanatic
                • Jan 2012
                • 5203

                #8
                Originally posted by Kipster
                I have a set of solar panels that put out a nominal 60V. My inverter is rated at 48V with a disconnect at 60V. When I connect them together, the inverter gives an over-voltage error and dis-connects. Is there a simple way to bring the voltage down by several volts so the inverter will work?
                The simplest solution might be to build a (powerful) shunt regulator that limits the panels to
                58V; not very high tech. It would cut off when inverter loads pulled the panels lower than that.

                The basic problem is, battery inverters are built to run on the useful range of a battery. Panels
                with a V Max Power of 60V can be expected to have a V Open Circuit of 72V, and even more in
                winter. The wide range may not fit into an inverter capability.

                You didn't give Vmp & Voc, or the general component power and arrangement of panels. It
                might be possible to "fine tune" panel voltage by shorting out a bypass diode or 2, depending
                on the panels; that power would be lost.

                If you got that working, any cloud drifting by or load surge (motor startup) could draw more
                power than the panels can deliver at that instant, and the whole system will shut down. If
                you don't live in a cloudless desert with very consistent loads, this could happen all the time.
                Don't forget, available power is going to be changing with time of day as well.

                If you were trying to run some relatively small DC loads (TV, laptop, etc), there are now
                available telecom style DC-DC converters that will accept an input range of 36V to 72V. That
                subject to the panels capability to deliver the needed power. good luck, Bruce Roe

                Comment

                • Sunking
                  Solar Fanatic
                  • Feb 2010
                  • 23301

                  #9
                  Originally posted by Kipster
                  So even without a battery in the system, a charge controller is still required? I hope you'll pardon my ignorance, I'm just getting started so I'll likely ask some ignorant questions. Or do I just need to bite the bullet and add batteries to the system?
                  You are going to have a lot of FUN. More than bite the bullet, try burn a lot of cash in the fireplaceN. .................................................. ....At 48 volts tells us you have more than 1000 watts of solar panels. If you have a 2000 watt panel the minimum size controller you can use is 40 amps. That will cost you peanuts ($300 to $400) compared to the minimum size battery required. The real FUN begins when you go to buy a 48 volt 400 AH minimum battery. It is so much FUN you get to do it every few years replacing that 1000 pound $3600 battery every 3 to 5 years. Have lots of FUN with it and get a lot of help moving it into place. Let the FUN begin and dig deep into your pockets and bank account. Told you it would be FUN.
                  MSEE, PE

                  Comment

                  • solar pete
                    Administrator
                    • May 2014
                    • 1816

                    #10
                    Originally posted by Kipster
                    I have a set of solar panels that put out a nominal 60V. My inverter is rated at 48V with a disconnect at 60V. When I connect them together, the inverter gives an over-voltage error and dis-connects. Is there a simple way to bring the voltage down by several volts so the inverter will work?

                    Sorry if this question has already been addressed. I searched and could not find it.

                    Thanks!
                    Hello Kipster and welcome to the neighborhood. I think we need more info

                    Brand and type of panels and how many
                    Brand and type of inverter
                    Where are you
                    What are you trying to achieve

                    I dont think you can expect any meaninful replies with out a way more detailed run down of just what you are trying to do and with what equiptment, cheers.

                    Comment

                    • Mike90250
                      Moderator
                      • May 2009
                      • 16020

                      #11
                      My 48V inverter runs all the way up to 68v before shutdown.

                      But except for grid tie inverters, you will need a charge controller and battery.
                      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

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