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Internal Resistance of a Lead Battery

  1. Sep 10, 2012 #1
    Anyone knows what is the approx. internal resistance of a lead battery, say, 12V, 20Ah.
    Thanks
     
  2. jcsd
  3. Sep 10, 2012 #2
    Lead acid batteries typically have an internal resistance around 20 milliohms.
     
  4. Sep 11, 2012 #3
    Thanks Crosstalk for replying me.
    You said 20 mOhms for a typical lead acid battery. But what is the typical ? 20, 40 or 100Ah ? (12V).
     
  5. Sep 11, 2012 #4
    I'm not 100% sure on this, but I don't think that the battery's capacity matters.
     
  6. Sep 11, 2012 #5

    nsaspook

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    Measurement of Internal Resistance: This is a for smaller cells but the principle is the same for "a typical lead acid battery". The IR changes as the battery ages and with State of Charge.
    http://data.energizer.com/PDFs/BatteryIR.pdf
    The battery construction (for Lead-Acid) affects IR, with AGM batteries having the lowest IR and Gel cells usually the highest for the same Ah rating.
     
  7. Sep 11, 2012 #6
    I just think that the higher the capacity, the bigger the electrode plates, so the internal resistance should be smaller.
     
  8. Sep 12, 2012 #7

    nsaspook

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    That's mainly true for the same type of battery construction but the total ionic resistance is a combination of factors like electrolyte conductivity, separator ionic resistance, ion mobility and electrode surface area.

    Values for several different sealed valve regulated types.
    3 milliohm 226Ah: http://www.power-sonic.com/images/powersonic/sla_batteries/pg_series/PG-12V200_11_Jan_12.pdf
    3 milliohm 140Ah: http://www.power-sonic.com/images/p...s_psg_series/12volt/PS-121400FR_11_Feb_21.pdf
    5 milliohm 154Ah: http://www.power-sonic.com/images/powersonic/Info%20for%20PHR%20section%20of%20website%2011%20Nov%2015/PHR-12500_12_July_2.pdf [Broken]
     
    Last edited by a moderator: May 6, 2017
  9. Sep 12, 2012 #8
    Hi nsaspook, I agree that it depends on many other factors, and Ah capacity is the most important.
    Thanks for the documents.
     
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