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Thread: Battery Help!

              
   
   
  1. #1
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    Battery Help!

    Hi all,
    After seeing all of your amazing builds, I have been inspired to build my own E-conversion. However, I know almost nothing about lithium batteries, BMSs or charging technologies and so I would love your advice before I blunder in and spend too much money on the wrong thing!

    I will be using:
    QS Motor 3Kw 48V hub motor
    Kelly Controller KLS7254N

    As far as I understand: the battery uses 50A continuous and 100A peak, so I need a 48v battery that can provide those Amps. Is that right?
    Some questions:
    The BMS is attached to the battery (?) so would a battery that I buy come with a BMS pre installed. Do I need to program or edit the BMS to ensure that it keeps the cells in the battery balanced and with enough voltage? Or can I leave it to it, and use / charge the battery as I would with a lead-acid battery?
    Is it better to get a battery custom built with the correct voltage / amperage output with a BMS that can handle that?
    I think I have two mounting places for batteries, is it better to buy two 48v batteries (each with a BMS) and mount them in parallel, or two 24V batteries and mount them in series (with a BMS each, or one for both?)

    Apologies if these questions have been answered elsewhere! I worry most things on this forum go straight over my head!
    Thanks in advance for any and all help / advice!!

  2. #2
    Member Electric Cowboy's Avatar
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    A lot of these answers depend on your build. You might want to consider one of the Boom Motos. They are not as polished as Zeros or Energicas, but they are 10kW hub motors with 6-9kwh batteries. and they cost $6500 to $7500 they are reasonable quality for the cost, and EASILY hackable. Way better to start with one of these and modify than to build from scratch if you are new. It will also help you learn a lot.

    They aren't perfect, but they are good enough for their price.

  3. #3
    Senior Member Stevo's Avatar
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    Quote Originally Posted by 4r3st3r View Post
    Hi all,
    Some questions:
    The BMS is attached to the battery (?) so would a battery that I buy come with a BMS pre installed. Do I need to program or edit the BMS to ensure that it keeps the cells in the battery balanced and with enough voltage? Or can I leave it to it, and use / charge the battery as I would with a lead-acid battery?
    Is it better to get a battery custom built with the correct voltage / amperage output with a BMS that can handle that?
    I think I have two mounting places for batteries, is it better to buy two 48v batteries (each with a BMS) and mount them in parallel, or two 24V batteries and mount them in series (with a BMS each, or one for both?)
    If you buy from a salvage yard to get a good deal on Nissan Leaf modules or Chevy Bolt modules you will need to learn how to cut them apart.
    Same with a Tesla pack, but all of those flashlight batteries will be a challenge to incorporate a BMS. The pouch cell modules are easier to deal with.
    If you are building your own pack, like I did, you can arrange them anyway you want or need to. since this is your first build, try to go with one stack in series and figure out how to mount them on your frame space. They can be divided into groups. I have 3 groups of battery pouches all wired in series. There are a few BMS options available,,,, you'll have to do some research. I went with the Thunderstruck BMS.
    ElectricCowboy has some good advice for you, But if you want to do your own from scratch, AND if you have the ability to weld and fabricate your own mounts and stuff, you can build your own for 1/2 the cost of a Boom Moto
    Current rides: '96 Honda Ohlins VFR, '03 Cannondale C440R, '03 Cannondale Cannibal, '06 Yamaha 450 Wolverine 4x4
    Current builds: eVOR.v3.3
    WORX.VOR.v3.2

  4. #4
    Old EV Racer EVcycle's Avatar
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    Chevy Volt batteries come in a 48 volt single pack. Ready to roll for around $500.
    I have used them in several projects. You can purchase 50.4V Lithium chargers for about $250.
    Use the Controller as a BMS and have fun!

    Ed
    EV Ed
    Never let being a responsible adult get in the way of passion and curiosity.
    Motenergy.com
    Ev album 2456, 2458, 2457, 2681, 3456, 3630

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