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    Simple e bike battery question

    Hello, so I have a quick question about building a battery. I plan on building a colossal 4kw e bike battery, and when it's done I plan on pulling about 200-300 amps from it to power my motor. Now my question is when I assemble the battery in series and in parallel and I'm all done, I finally have to connect/solder the discharge wires and the charging wires. Now in order for me to pull such amps (200-300) I would need really thick awg wires probably around 1 awg or thicker. My question is how am i going to Connect such a thick wire to the top of a cell or cells... The wires are really thick I can imagine it would be very difficult. And for charging the pack I'm thinking I'm going to be using a 20 amp charger, so the thickness of the wires shouldn't be that thick but I'm not sure exactly how much space you have on the bms to solder the positive and negative....

    #2
    Originally posted by Electricbiker100 View Post
    Hello, so I have a quick question about building a battery. I plan on building a colossal 4kw e bike battery, and when it's done I plan on pulling about 200-300 amps from it to power my motor. Now my question is when I assemble the battery in series and in parallel and I'm all done, I finally have to connect/solder the discharge wires and the charging wires. Now in order for me to pull such amps (200-300) I would need really thick awg wires probably around 1 awg or thicker. My question is how am i going to Connect such a thick wire to the top of a cell or cells... The wires are really thick I can imagine it would be very difficult. And for charging the pack I'm thinking I'm going to be using a 20 amp charger, so the thickness of the wires shouldn't be that thick but I'm not sure exactly how much space you have on the bms to solder the positive and negative....
    Do you have a link to the BMS that you are planning to use?

    This is a very high amount of current. What is the system voltage? Motor and controller links? I am very curious about what controller you would use and how many FETs. Are these the parts https://electricbike.com/forum/forum...s-have-arrived ? Is this the motor http://www.cnqsmotor.com/en/article_...Motor/260.html ? There are a lot of monster controllers here http://www.cnqsmotor.com/en/article_...oller/108.html .

    FYI I have pulled as many as 104.9A in a 72V system with 10 gauge motor wires. My battery wires are 8 gauge. I have two 36V 10s9p batteries (each battery has its own 100A BMS) in series. I have a Cromotor which is rated for 4500W continuous, but when I pull 100A, the 50mm wide stator motor heats up very quickly. On a ride where I pull 100A, the motor heats up to 100 degrees C within a few minutes, so really only good for a drag racing application.
    Last edited by commuter ebikes; 09-20-2018, 11:51 AM.

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      #3
      Hey, the motor I plan on using is the golden motor with there controller it's huge and can handle a ton..... Here's the link

      https://goldenmotor.com 10kw motor easily capable of double.
      The battery I plan on building is a 96v which is about 25s 10p. The bms I'm going to order is from Ali express and they custom make it you tell them the specs. I'm really surprised you ran such amps through your 8 awg wires. However I really want to be sure about what awg I use because I want to have the least resistance. And possibly I might push more than 300 amps. So maybe someone who's done this might have a idea for what I could do.

      Comment


        #4
        Originally posted by Electricbiker100 View Post
        Hey, the motor I plan on using is the golden motor with there controller it's huge and can handle a ton..... Here's the link

        https://goldenmotor.com 10kw motor easily capable of double.
        The battery I plan on building is a 96v which is about 25s 10p. The bms I'm going to order is from Ali express and they custom make it you tell them the specs. I'm really surprised you ran such amps through your 8 awg wires. However I really want to be sure about what awg I use because I want to have the least resistance. And possibly I might push more than 300 amps. So maybe someone who's done this might have a idea for what I could do.
        Do you have a link to the specific motor and controller that you will be using? I am curious.

        Comment


          #5
          Yes the links are below.

          Motor
          https://www.goldenmotor.ca/products/...ir-Cooled.html

          Controller
          https://www.goldenmotor.ca/products/...ontroller.html

          Comment


            #6
            Originally posted by Electricbiker100 View Post
            Motor looks great. The controller says 72V, but you mentioned 96V.

            Make sure to take the time to make a thread on your build here on the forum. Pictures, links, problems, solutions, questions, etc.

            Have you done the math on whether or not your cells can provide the desired current? A larger capacity battery can help with this. I have 180 2200mAh cells in a 19.8Ah 72V battery, and that battery is limited as to what it can do. It is stellar hot off the charger, but near discharge it is weak sauce.
            Last edited by commuter ebikes; 09-20-2018, 11:16 PM.

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              #7
              Yea the controller if you read in the description it also says 96v, and the cells im going to be using have a rating of 3500mah with a 10cdr, which after the total 300+ cells would be plenty of amps and some to spare.

              Comment


                #8
                Originally posted by Electricbiker100 View Post
                Yea the controller if you read in the description it also says 96v, and the cells im going to be using have a rating of 3500mah with a 10cdr, which after the total 300+ cells would be plenty of amps and some to spare.
                That would definitely be enough juice!

                cdr = cell discharge rate, I assume. As in 10C.

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