hello. can i add a 6v 10 ah battery to a 48v 10ah pack made of 12v 10ah batteries?

Discussion in 'General Electronics Chat' started by jmcx3, Apr 5, 2015.

  1. jmcx3

    Thread Starter New Member

    Apr 5, 2015
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    Its an electric bike which is 48v now but I'm trying to gain more speed by adding 6v i tried adding a 12v 10ah but its too much volts
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Should work with SLA batteries. Best if all batteries come from the same manufacturer, and are all of the same type.
     
  3. tom_s

    Member

    Jun 27, 2014
    285
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    /me ask the propers question - how these batteries being charged?

    edit: individually or all at once?
     
    Last edited: Apr 7, 2015
  4. jmcx3

    Thread Starter New Member

    Apr 5, 2015
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    0
    Individually i have 6v and 12v chargers but im not sure if ill just upgrade the controller because i heard the motor can do 3000W safely for a small distance so not sure if ill buy a 48v 30 amp controller instead to make it 1500w
     
  5. tonyStewart

    New Member

    May 8, 2012
    22
    3
    The key to ensuring batteries do not get reverse biased is the specific gravity in each cell and the effective series resistance must be matched within 2% so that at end of charge they do not become 50% mismatched and one cell becomes the weak link and gets destroyed.

    Matching may be impossible, but I would suggest using a battery with a bit more Ah capacity than the rest, so it does not become the weak link.


    1~2% Cell balancing is given when batteries cells are replicated t the factory.

    Vendor & Process changes can cause big mismatch as well as aging.

    This is the reason batteries fail as one becomes weaker than the rest. A perfect set is when all age at the same rate and expire together. This doesn't always happen when stressed by temperature and high surge currents.

    A Specific Gravity tester and a logbook are your friend.

    Then you may have to worry about burning out your motor or significantly reduce armature, brush life. Consider adding temperature sensors or arc sensors or be creative.

    If this is not possible, one can sometimes measure temperature by the resistance change in copper windings. You can also tell when the torque reduces when it gets too hot but this can also be the rapid rise of battery ESR when low in SOC.
     
    Last edited: Apr 8, 2015
  6. tom_s

    Member

    Jun 27, 2014
    285
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    [random thoughts - lighting a bbq with a tin of petrol]

    electric bikes are designed to work within safe operating ranges eg: volts/current. hence a 48v motor is designed to work with a 48v supply source. adding another 6v to it would (effectively) void the warranty and as TonyStewart above me has typed 'Then you may have to worry about burning out your motor or significantly reduce armature, brush life. '

    being on the safe side, personally i wouldn't add the additional battery.
     
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