battery sag

Discussion in 'Battery Junkies / Chargers' started by mokeife, Nov 8, 2016.

  1. mokeife

    mokeife Bronze Contributor

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    why does my battery sag drop 1 volt and other times it will drop 1.5 volts? this is on both of my mods a vcp big pig and a custom series/parallel device. batteries are lg hb2's drop seems to change on both sets. i am just curious as to whats going on here that causes the differences in sag. ps.all my contacts are clean thanks
     
  2. HondaDavidson

    HondaDavidson Gold Contributor Member For 1 Year

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    Are builds the same? You do realize that all metal and electronics have resistance or consume power.... So the more metal or circuitry there is between the battery the higher the sag. Also the charge state of the batter affects sag. Lower the charge the more the sag.

    Are you using married sets for your Multi battery mods? If not this can also contribute.
     
  3. mokeife

    mokeife Bronze Contributor

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    yes the builds are the same this happens on the same .34 build just curious as to why
    it changes every now and then and it doesnt seem to correlate with how charged my batteries are and they are both
    married sets
     
  4. dr_rox

    dr_rox Senior Moderator Staff Member Senior Moderator VU Donator Bronze Contributor Member For 3 Years

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    Battery voltage sag is a result of the chemical reaction and ion migration that takes place inside the battery to supply current to a circuit.
    It's like having your headlights on and turning the ignition key to start, the lights dim.
    Battery cannot keep up with load demand. Battery has a de facto governor on it.
    It can only work so fast.
    Dirty battery contacts increase the resistance of the circuit, so the current demand is less, so less sag.
    To test this, get out a meter. Test battery voltage. Clip in a resistor. What is the voltage?
    Resistors limit current.
    To get a better idea of what is going on, you need to look at the battery discharge curves. They are not straight lines - which is what you would see if you were using an AC 'power pack' to drive the circuit, since delivery is not governed by chemistry.
     
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  5. stopngo1000

    stopngo1000 New Member

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    Hey guys,

    I have been trying to understand voltage drop and battery sag. I’m looking to buy my first squonker which is also my first mech mod. I have a good grasp on battery safety and ohms law but should I be concerning myself with voltage drop? I feel like anything I hear about it is just “how hard” it hits. I don’t want to miss out on any additional safety concerns.
     
  6. HondaDavidson

    HondaDavidson Gold Contributor Member For 1 Year

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    If your not pulling max amps with your builds....or running huge ass coils.... you don't really need care about it....

    Sent from my SCH-I605 using Tapatalk
     

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