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12 volt 2000 watt inverter charger recommendations

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  • #16
    Originally posted by Sunking View Post
    BS half truth. NEC and all electrical codes have minimum wire gauge standards vs current. Example a 50 amp circuit requires a minimum 6 AWG wire. You cannot use anything smaller. At 100 requires a minimum 4 AWG, and at 200 amps require 2/0. Whoever told you 1/0 is good for 300 amps is full of chit and should be ignored and shot. 300 amps requires 4/0 AWG.
    A wire manufacturer told me 1/0 was good for 300 amps on their website but I thought that was pretty ridiculous myself and I don't even know anything.

    Magnum only specs 2/0 wire for 300 amps and 4/0 for 400 amp in free air less than 5 feet in their manuals. Is Magnum full of chit? I thought they were a reputable manufacturer.

    Why do you say a consumer is already pushing it working with 4 awg? Is because of terminating wire that size or another reason?

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    • #17
      Originally posted by somekevinguy View Post

      A wire manufacturer told me 1/0 was good for 300 amps on their website but I thought that was pretty ridiculous myself and I don't even know anything.

      Magnum only specs 2/0 wire for 300 amps and 4/0 for 400 amp in free air less than 5 feet in their manuals. Is Magnum full of chit? I thought they were a reputable manufacturer.

      Why do you say a consumer is already pushing it working with 4 awg? Is because of terminating wire that size or another reason?
      The problem is the load may be much lower then the amperage a 4 awg can handle for most of the time and higher a very short period of time. That allows the 4 awg to work but it will get hot. But with an inverter that can accept a much higher load for a longer time and then the amps will increase and can exceed the 4 awg rating by a lot.

      When you design your wire size you need to consider the highest amps it may see and then protect it with the proper fusing. If you don't use a wire big enough to handle the amps going through it then the wire gets real hot and burns up.
      Last edited by SunEagle; 12-10-2018, 03:53 PM. Reason: spelling

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      • #18
        Originally posted by SunEagle View Post

        The problem is the load may be much lower then the amperage a 4 awg can handle for most of the time and higher a very short period of time. That allows the 4 awg to work but it will get hot. But with an inverter that can accept a much higher load for a longer time and then the amps will increase and can exceed the 4 awg rating by a lot.

        When you design your wire size you need to consider the highest amps it may see and then protect it with the proper fusing. If you don't use a wire big enough to handle the amps going through it then the wire gets real hot and burns up.
        Yeah like I said Magnum is specing 4/0 with a 400 amp fuse and 2/0 with a 300 amp fuse which I know doesn't agree with NEC. I thought they were one of the more reputable companies. I'm wondering why they do this? Do the NEC charts just assume longer runs than these super short runs of 5 feet or does run length not even matter for thermal limits and then you have to go even even bigger from there for voltage drop based on run length?

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        • #19
          Originally posted by somekevinguy View Post

          Yeah like I said Magnum is specing 4/0 with a 400 amp fuse and 2/0 with a 300 amp fuse which I know doesn't agree with NEC. I thought they were one of the more reputable companies. I'm wondering why they do this? Do the NEC charts just assume longer runs than these super short runs of 5 feet or does run length not even matter for thermal limits and then you have to go even even bigger from there for voltage drop based on run length?
          The wire insulation rating is part of what determines the amount of amps it can handle. When you run more than 3 wires in an enclosed raceway (pipe, conduit, trough) you have to lower (or de-rate) the amps rating. Some wire insulation is only good in dry conditions other is rated for dry or wet.

          If you can cool the wire in open air it can withstand higher amps then it is rated at, for brief periods. Then it gets hot and can melt the terminations or insulation.

          Some manufacturers state you can run a lot more amps through a wire then it is intended because they think it will be for only a short time and they aren't held to meeting NEC standards just their companies insurance limitations.
          Last edited by SunEagle; 12-10-2018, 04:22 PM. Reason: added last sentence

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          • #20
            Originally posted by SunEagle View Post

            The wire insulation rating is part of what determines the amount of amps it can handle. When you run more than 3 wires in an enclosed raceway (pipe, conduit, trough) you have to lower (or de-rate) the amps rating. Some wire insulation is only good in dry conditions other is rated for dry or wet.

            If you can cool the wire in open air it can withstand higher amps then it is rated at, for brief periods. Then it gets hot and can melt the terminations or insulation.

            Some manufacturers state you can run a lot more amps through a wire then it is intended because they think it will be for only a short time and they aren't held to meeting NEC standards just their companies insurance limitations.
            Yeah they mention in the manual "may not meet all NEC or local codes" and I thought that was odd they were even pointing it out but still giving you those numbers.

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            • #21
              Originally posted by somekevinguy View Post
              .......Why do you say a consumer is already pushing it working with 4 awg? Is because of terminating wire that size or another reason?
              Terminating the wires. And stripping them with out using a knife and cutting critical strands. I have thermal strippers that melt the insulation away. They stink a lot, but never nicks the wire.

              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

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              • #22
                Originally posted by Mike90250 View Post

                Terminating the wires. And stripping them with out using a knife and cutting critical strands. I have thermal strippers that melt the insulation away. They stink a lot, but never nicks the wire.
                Oh OK. I've had all the stuff to terminate wires up to 4/O for 30 years but maybe I'm not your average consumer.

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                • #23
                  Originally posted by somekevinguy View Post

                  Yeah they mention in the manual "may not meet all NEC or local codes" and I thought that was odd they were even pointing it out but still giving you those numbers.
                  And as SK and others have pointed out, the "NEC or local codes" are to protect the wire. Voltage drop at 120 or 240 Volt (absolute which is what heats wire) is a far lower % than at 12 Volt. You need to be more conservative with lower voltage systems, not less.

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                  • #24
                    Originally posted by somekevinguy View Post
                    Yeah they mention in the manual "may not meet all NEC or local codes" and I thought that was odd they were even pointing it out but still giving you those numbers.
                    That is put there by the lawyers so you cannot sue them because you Joe Consumer are ignorant. Consumers are not smart enough to read between the lines and see the RED FLAG warning; "may not meet all NEC or local codes" is one heck of an understatement. If you knoew what it really takes would quickly realize the terminals are not big enough and nothing is designed to do what it claims. Kind of hard to sell a POS if you admit it it s POS and dangerous.

                    MSEE, PE

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