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  • help connecting inverter to batteries

    We have an already insteady installed sollar system which the use of WS-C2430 20A Solar Charge Controller already. Meanwhile, the engineers installed it without an Inverter so we have limited load. Now, we just bought a 2000 watt inverter which we want to join to it so it can carry our computers. please how do i go about thw conectivity?

  • #2
    Originally posted by xlaxtee View Post
    We have an already insteady installed sollar system which the use of WS-C2430 20A Solar Charge Controller already. Meanwhile, the engineers installed it without an Inverter so we have limited load. Now, we just bought a 2000 watt inverter which we want to join to it so it can carry our computers. please how do i go about thw conectivity?
    Start with the manual for the inverter. It should say what size cables and fuse to use with it. These generally connect directly to the battery terminals, so that you have the least resistance.
    note: I have no idea if the gear you bought, is suitable for the gear you already have. You are on your own.
    spreadsheet based voltage drop calculator:
    http://www.solar-guppy.com/download/...calculator.zip
    http://www.solarpaneltalk.com/showth...oss-calculator

    http://www.mike-burgess.org/PVinfo_2.html

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,
    battery lugs http://tinyurl.com/LMR-BigLug
    Setting up batteries http://tinyurl.com/LMR-NiFe

    gear :
    Powerfab top of pole PV mount | 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

    Comment


    • #3
      bump
      spreadsheet based voltage drop calculator:
      http://www.solar-guppy.com/download/...calculator.zip
      http://www.solarpaneltalk.com/showth...oss-calculator

      http://www.mike-burgess.org/PVinfo_2.html

      solar: http://tinyurl.com/LMR-Solar
      gen: http://tinyurl.com/LMR-Lister ,
      battery lugs http://tinyurl.com/LMR-BigLug
      Setting up batteries http://tinyurl.com/LMR-NiFe

      gear :
      Powerfab top of pole PV mount | 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

      Comment


      • #4
        What is ment by"we have limited load"?
        EVERY inverter comes with a manual. but it is pretty obvious that you will be connecting the red terminal on the inverter to the battery and the black terminal to the black terminal on the battery.. there is not to many other ways to connect it. As its a 2000w inverter you wil need at least #2 cables with good well crimped solid lugs. Use the shortest cable that is practical,,, reduced losses.

        Comment


        • #5
          connecting inverter

          I have three 12v agm battteries connected in parallel do i connect my inverter cable clamps on opposite ends on the bank?
          ie positive on battery 1 and negative on battery 3 ?
          Thanks for your h3lp!

          Comment


          • #6
            yes and the charging circuit also
            Rich
            WWW.solarsaves.net

            NABCEP certified Technical Sales Professional

            http://www.solarpaneltalk.com/showth...Battery-Design

            http://www.calculator.net/voltage-drop-calculator.html (Voltage drop Calculator among others)

            www.gaisma.com

            Comment


            • #7
              this link has the answers you seek.

              http://www.smartgauge.co.uk/batt_con.html (connect batteries on diagonal )

              2 batteries in parallel is OK. add more, and it gets more complex.
              spreadsheet based voltage drop calculator:
              http://www.solar-guppy.com/download/...calculator.zip
              http://www.solarpaneltalk.com/showth...oss-calculator

              http://www.mike-burgess.org/PVinfo_2.html

              solar: http://tinyurl.com/LMR-Solar
              gen: http://tinyurl.com/LMR-Lister ,
              battery lugs http://tinyurl.com/LMR-BigLug
              Setting up batteries http://tinyurl.com/LMR-NiFe

              gear :
              Powerfab top of pole PV mount | 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

              Comment


              • #8
                connecting inverter

                thanks for the help! great quick responses!
                I just picked up three new upg thirty five ah 12 v batteries and wham! the power went out! what a great gift to my wife ( who is a tele worker and works at home) when i was able to get her back online without interruption. Any suggestions for interconnect cables? my research tells me to play it safe and go with awg 2 is that correct? i have a total or 105 ah going to a power bright 1100 watt inverter.
                u mentioned that i should put my deltran battery tender jr charger on the same connect point as my inverter is this also true for my new thirty amp charge controller( building solar panels as we text) this seem like a few too many items for one terminal pls advise
                Thanks again for your help n patience i know working with newbies can be a challenge!

                Comment


                • #9
                  4 gague is probably adequate but 2 gague will reduce resistence so you have less loss in the cable. Too big of a cable should not be an issue. too small would be.

                  I just purchased a 1500 W Inverter/transferswitch/charger combo unit to automatically support a sump pump. The supplier recommended 4 gague 36" long cables to the battery. I I needed them longer than that I probably would have gone to 2 gague.

                  Comment


                  • #10
                    connecting inverter

                    [I] went with 2/0 wire for my interconnects and awg 2 for my inverter wire with ring terminals to replace the clamps im only i have only 105
                    amp hours of battery and the inverter is only going to throw out 250-400 watts max but i wanted to give my self some room to grow also.
                    did i over do it with the wires or is it a case that
                    you cant go too big??
                    thanks!

                    Comment


                    • #11
                      I would always size the wire for the max size the inverter can handle. You might only be pulling 400 watts today, but tomorrow you might add load and would want the cable to be properly sized.

                      I would say you did good.

                      Comment


                      • #12
                        You figure out what your peak load is (on the inverter) and calculate how many amps the DC cable has to supply to not drop below the inverter cut-out voltage.

                        I have a 1/2 hp pump, that pulls 1,000 watts running. It's likely 8x that for startup (for 2 seconds) so I have to assume, 8,000watts @ 48V = 166 amps That is now my target (OK I used 500A) to plug into the voltage drop calculator to see what gauge I need for ALL the interconnects in my batteries (I'll have 40, 1.25V, 700ah batteries, so that adds up to a lot of interconnects and wire)

                        Using the spreadsheet calculator in my .sig

                        500A & 20 feet, using single "0" wire [ 1/0 ] gives me about 1V drop, or 2% loss, under a VERY heavy, 500A peak surge.500A_0gauge.jpeg


                        As you battery voltage goes lower, the amps on the input to the inverter go up:

                        48V = 500A =1v loss 1/0 wire (2%loss) no problem

                        24V =1099A = 2.5v loss 1/0 wire (9% loss) inverter may disconnect from undervoltage

                        12V =3024A =4v loss 1/0 wire (75% loss) (inverter shuts off from undervoltage)

                        12V =2420A =2v loss 4/0 wire (45.5% loss) (inverter shuts off from undervoltage)

                        so 12V system can't be done. As the wire losses increase, the voltage drop increases, reducing the voltage at the inverter, and the amps go up, thats why in the 24v & 12v examples, it's not a simple doubling f the amps, the inverter is seeing the 22v supply & 8V supply, and pulls even more amps, till something frys.
                        spreadsheet based voltage drop calculator:
                        http://www.solar-guppy.com/download/...calculator.zip
                        http://www.solarpaneltalk.com/showth...oss-calculator

                        http://www.mike-burgess.org/PVinfo_2.html

                        solar: http://tinyurl.com/LMR-Solar
                        gen: http://tinyurl.com/LMR-Lister ,
                        battery lugs http://tinyurl.com/LMR-BigLug
                        Setting up batteries http://tinyurl.com/LMR-NiFe

                        gear :
                        Powerfab top of pole PV mount | 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

                        Comment


                        • #13
                          Have you actually measured the surge watts of your pump to be 8000 watts?

                          I have a wump pump that goes on for 15 to 20 seconds, then turns off. I have measured the pump to pull 6 amps AC (about 720 watts) or about 65 amps DC from the battery through the inverter. This is a 1000W continous/2500 surge watts inverter.

                          I would have expected maybe 2X surge at start-up. I would expect the inverter to shut down if my pump were to pull 8X its running wattage. That would be over 5700 watts.

                          What am I not understanding? Where has my reasoning gone wrong? Can your pump REALLY pul 8X on start?

                          Comment


                          • #14
                            large motors (even small ones) can pull 3-10x running power, on start up. The surge only lasts a second, and to measure it, you need a $300 peak hold meter, normal meters can't capture the short peak. Some inverters handle peak surges better than others.

                            Here's an article from Homepower http://homepower.com/article/?file=HP98_pg140_QandA_4

                            and from a generator info page: http://www.generatorjoe.net/html/startingload.html At the bottomWell Pump Starting Current
                            This test measured the starting current for a well pump motor. The motor is rated 3/4 hp and 240V. Results of one measurement are shown in the plot below. It shows a maximum inrush current of about 18 amps which lasts only about 0.2 seconds.

                            That comes up to 4320 watts starting, 1440w running. Not as bad as my worst case example, but 4300w from a 24V system is 180amps DC from the batteries.
                            spreadsheet based voltage drop calculator:
                            http://www.solar-guppy.com/download/...calculator.zip
                            http://www.solarpaneltalk.com/showth...oss-calculator

                            http://www.mike-burgess.org/PVinfo_2.html

                            solar: http://tinyurl.com/LMR-Solar
                            gen: http://tinyurl.com/LMR-Lister ,
                            battery lugs http://tinyurl.com/LMR-BigLug
                            Setting up batteries http://tinyurl.com/LMR-NiFe

                            gear :
                            Powerfab top of pole PV mount | 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

                            Comment


                            • #15
                              mike and sunking

                              Hey guys
                              dumb question. Are alligator clamps as good as ring terminals for connecting inverter to battery bank??
                              they sure are convenient
                              thanks for humoring me on this basic question!

                              Comment

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