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Lithium-ion multiple batteries on parallel - same challenge as Lead Acid or not?

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  • #46
    Originally posted by bcroe View Post

    Electric signaling and power was well in hand by the late 1800s, with motors, phones, and crude
    wireless. WWII was fought without transistors. Some of us think the electronic age started with
    the 1908 invention of the vacuum tube (amplifier), which AT&T developed for coast to coast calls
    by 1914. Shortly many industries were using the tube.

    Zero carbon footprint for this house, no batteries, no firewood. How many off griders can say that?
    Bruce Roe
    Off topic.

    Bruce. Try to stay warm and safe during the blizzard heading your way.

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    • #47
      Originally posted by SunEagle View Post
      Off topic.
      Bruce. Try to stay warm and safe during the blizzard heading your way.
      Yes, it is just starting here, thanks. But we are used to them, unlike fires, hurricanes, and floods
      hitting so many. This will be a very low production day, I had better read the inverters before they
      get shut down.

      What not many realize, the transistor had advantages over tubes, but it was the integrated circuit
      (1957) that revolutionized electronics. The first ICs at work half a century ago had 4 transistors,
      the one I did a couple decades later had 175,000, and they are at some power of billions last I heard.
      Tubes are still around, there is a 1940 style magnetron in every microwave oven. Bruce Roe

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      • #48
        Originally posted by bcroe View Post
        last I heard. Tubes are still around, there is a 1940 style magnetron in every microwave oven. Bruce Roe
        And they will remain for a long time to come with respect to commercial high power RF Amps. Although today you can buy a 1 Kw Solid State using MRFX1K80H a 1 Kw 1 to 470 Mhz amp. Just finnished building a 2000 watt linear amplifier. Used 48-Volt Telcom Rectifiers as the power supply, and a AGM battery as a buffer. However not easy to work with because you also need to be a plumber because it requires water cooling. Not real efficient as Class AB amplifier go of roughly 40%. FM I can only run at 800 watts, SSB up to 2000 watts. Keeps the birds off the wire antenna though. Now if I can just focus the beam on the ^!@#$& dang monkeys.

        MSEE, PE

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        • #49
          Been away a few days - 2 pages of off-topic - Can we get back on track?

          "Lithium-ion multiple batteries on parallel - same challenge as Lead Acid or not?

          --------------------
          Norwegian off grid cabin owner
          Panels facing south

          - Kyocera panels 135W
          - Tristar 60A MPPT
          - Victron 3000w/12V / 120A

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          • #50
            Originally posted by Roil View Post
            Been away a few days - 2 pages of off-topic - Can we get back on track?

            "Lithium-ion multiple batteries on parallel - same challenge as Lead Acid or not?
            Sorry about that Roil, got distracted from an advocated/salesman ganja smoking nebster from Colorado, and Calaphonie user trying to figure out how to pay for electricity with other peoples money. Please accept my apology.

            Not it is not the same challenge because they are done differently. Pb batteries are paralleled at the String Level and self equalize given enough time when needed, and Li is paralleled at the Cell level and require either Vampire Boards (passive autonomous) used at the DIY level which is pretty much guaranteed to kill your batteries, or Active integrated with the charger.

            Rather than go through every method Davide Andrea a very good friend of mine wrote the book on BMS. He has one of the best websites on the internet. Considered working for him several years ago, but had no interest in living in Boulder. Check out his site and you can learn everything there is to know about lithium batteries and BMS. Check out the tutorials, white papers and why you parallel at the Cell level and not on the String level. You will also find just about every BMS, Lithium Ion Battery, Battery Pack, and Integrated Circuit made for Li batteries. It will take you a long time to go through it all, but when done you will have a really good idea of what is going on.

            Again my apologies. Davide also makes one good BMS from his own Integrated Circuit design made just for his company BMS product. Another good one for DIY is Orion. Use one of the Selector tools to find a BMS that will work for you. Just remember one thing. A BMS cannot balance an out of Balance Lithium Battery. They can only keep a Balanced pack Balanced with very minor tiny corrections.
            Last edited by Sunking; 11-26-2018, 08:10 PM.
            MSEE, PE

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            • #51
              Originally posted by Sunking View Post

              Not it is not the same challenge because they are done differently. Pb batteries are paralleled at the String Level and self equalize given enough time when needed, and Li is paralleled at the Cell level and require either Vampire Boards (passive autonomous) used at the DIY level which is pretty much guaranteed to kill your batteries, or Active integrated with the charger.

              Rather than go through every method Davide Andrea a very good friend of mine wrote the book on BMS. He has one of the best websites on the internet.
              Thank you Sunking I have some studying to do
              --------------------
              Norwegian off grid cabin owner
              Panels facing south

              - Kyocera panels 135W
              - Tristar 60A MPPT
              - Victron 3000w/12V / 120A

              Comment


              • #52
                Davide's written material on the disadvantages of paralleling strings is mostly misinformed or misleading, although its overall suggestion is true: it is often better to parallel first, then place in serial.

                But there are times when it is better (or even necessary) to place multiple serial strings in parallel, and it is perfectly doable. It usually costs more, but it comes with advantages.

                Please be careful heeding Sunking's regurgitated advice in this area. He does not have hands-on experience with the topology. And be skeptical of any material put out by BMS-producing companies. They are often great engineers, but they have to feed their families, and in my experience they are prone to overstating the concerns in their marketing material.

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                • #53
                  Oh yeah, I have nothing to sell. (Maybe I should!)

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                  • #54
                    Originally posted by nebster View Post
                    Davide's written material on the disadvantages of paralleling strings is mostly misinformed or misleading, although its overall suggestion is true: it is often better to parallel first, then place in serial.
                    That is is some funny stuff from someone who pretends to know what they are talking about. Try laying off the Ganja there in Colorado.
                    MSEE, PE

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