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Easy Charging Time and Charging Current Formula for Batteries. ( with Example of 120Ah Battery).

How to Calculate the time for battery Charging?
Easy Charging Time Formula for Batteries. ( with Example of 120Ah Battery).
Charging Time and Charging Current Formula for Batteries with Example of 120Ah Battery
 
 Here is the formula of Charging Time of a Lead acid battery.
Charging Time of battery = Battery Ah / Charging Current
 T = Ah / A
 

Example,
Suppose for 120 Ah battery, 
First of all, we will calculate charging current for 120 Ah battery. As we know that charging current should be 10% of the Ah rating of battery.
so charging current for120Ah Battery = 120 x (10/100) = 12 Amperes.
but due to losses, we can take 12-14Amperes for charging purpose.
suppose we took 13 Amp for charging purpose,
then charging time for 120Ah battery = 120 / 13 = 9.23 Hrs.
but this was an ideal case...
practically, this is noted that  40% of losses ( in case of battery charging)
then 120 x (40 / 100) = 48 .....(120Ah x 40% of losses)
therefore,  120 + 48 = 168 Ah ( 120 Ah + Losses)
Now Charging Time of battery = Ah/Charging Current
168 / 13 = 12.92 or 13 Hrs ( in real case)


 Therefore, an 120Ah battery would take 13 Hrs for completely charging ( with 13A charging current).

By: Wasim Khan
http://www.electricaltechnology.org

37 comments:

  1. there is some error in calculation for 120 ah and 13 amps it would be 9.23 bt u have type as 150 instead of 120 so change it

    ReplyDelete
    Replies
    1. Dear Sudharsan M,U@
      Thank you so much for taking a valuable review.

      Delete
  2. Most battery manufacturers recommend sizing the charger at about 25% of the battery capacity (ah = amp hour capacity). Thus, a 100 ah battery would take about a 25 amp charger (or less). Larger chargers may be used to decrease charge time, but may decrease battery life. Smaller chargers are fine for long term floating, e.g. a 1 or 2 amp "smart charger" can be used for battery maintenance between higher amp cycle use. Some batteries specify 10% of capacity (.1 X C) as the charge rate, and while this doesn't hurt anything, a good microprocessor charger of the appropriate charge profile should be fine up to the 25% rate. You talk to different engineers, even at the same company, you get different answers.

    ReplyDelete
  3. Anonymous19:39

    i have battery in my home with ups
    NS-175 of Osaka company
    how i find its voltage nd ampere-hour rating...???
    plz tell me

    ReplyDelete
    Replies
    1. The rating of Osaka NS-175 battery is ( 12V, 175Ah)

      Delete
  4. Anonymous06:10

    thanks
    but can u telll how u find it??so that next time i also find it
    plz

    ReplyDelete
    Replies
    1. Just check the battery Code like NS-200, NS-175, NS- 120.
      So these are it Ah rating for instant, NS-200 = 200Ah, 12V.,,and we also know that these battery comes in 12V DC.

      Delete
    2. Anonymous12:22

      thanks.dear

      Delete
  5. Anonymous12:31

    could u please tell me how to increase the battery power..what are the specifications to be considered while bying a new ups...?

    ReplyDelete
  6. If i have a battery bank as follows:

    25 batteries(12v) x 120 Ah = 3000 A

    So in this case I need 300A rating for charging?
    In this case I need charge controller for 300A?

    Please can you help if this is correct?

    ReplyDelete
  7. sir i want to ask you that There is no difference in the 12v 120Ah and 220v 120Ah

    ReplyDelete
    Replies
    1. Dear,,,, 12V batteries comes in DC, while 220V is AC..... and we cant not store AC in batteries.
      Also the question is irrelevant, but refer to basic calculation
      12V x 120Ah = 1440Wh
      and for 220V
      220V x 120Ah = 26400Wh

      Delete
  8. Anonymous00:32

    Hi friends, I bought electrical scooter (Its name is Volta VS4 3000W, made in Turkey) . It has 60V,20A gel accumulator and charging valuse are 60v and 3A. How long does it take caharging time? User guide explains charging time is nearly between 6-8 hours. How can I find these charging durations?
    Thanks

    ReplyDelete
    Replies
    1. The accumulator [Battery] rating should be 60V, 20Ah.
      Thus charging current for 20Ah would be 10%. of it rating [20Ah].
      Therefore, [20Ah x 10]/100 = 2A.
      Ideally, the charging current for this battery would be 2A.
      but due to losses, we can take 2-3A for charging propose.
      Now charging Time = Battery rating / charging current
      = 20Ah / 3A = 6.6Hrs. ideal case.
      Due to 30 to 40% losses. This 60V, 20Ah battery would take 6-8 Hrs charging on 3A.
      Thanks

      Delete
  9. Hi sir ur blog is superb..
    i hav a general question that what will be the discharging time, and load capacity of a battery, how we can calculate that..

    ReplyDelete
    Replies
    1. Dear Reddy Marala.
      Read this article ..it is informative..
      http://www.electricaltechnology.org/2013/05/a-complete-note-on-solar-panel.html

      Delete
  10. Anonymous04:32

    Hi, my solar energy system comprises a 200watt-solar panel, a 10A(12/24volt-charge controller), 2 120Ah batteries and a 1000watt-invertor(24volts). How should I efficiently charge my batteries: in series or in parallel. Also, is it possible to watch TV while charging in parallel?

    ReplyDelete
  11. hi sir... what can i do to improve the efficiency of the cahrging time? means to make the charging time is less

    ReplyDelete
    Replies
    1. Increase the Charging current for less time..

      Delete
  12. dear ser weare charging 300 ah batery 10 hr with 10 amp then howmony unit corrent is taking from electricity

    ReplyDelete
  13. Anonymous23:25

    dear sir how can I find out that what ampere current my 12 volt
    charger produce

    ReplyDelete
  14. SIR I WANT KNOW ALL ABOUT BATTREYS PLZ SEND ANY LINK ABOUT THAT TOPIC ITS VERY USE FULL TO ME PLZ SIR

    ReplyDelete
  15. Sir can I run 1 Ton AC on 1000watt solar panel.

    ReplyDelete
    Replies
    1. http://www.electricaltechnology.org/2014/02/why-AC-rated-in-Tons-Not-in-kW-or-kVA.html

      Delete
  16. Anonymous09:31

    Dear Sir,
    i understood your explanation but was confused a little. Is the fixed rate 10% for charging current and can be same the rate charging with Charger, Inverter and Solar? let me known clearly, Sir?

    ReplyDelete
  17. sir , my battery is (33ah/20h) so what will be the charging current n time of that battery?

    ReplyDelete
  18. sir my dry cell battery of indus company is(33ah/20h) so what will be the charging current n time of the battery?(plz tell me wid formulae)

    ReplyDelete
  19. sir,
    130ah /12 vdc 8nos batteries in series so what is the correct charging current for this tubular batteries ...i am some what confusion pls clear

    ReplyDelete
  20. Sir,
    I want to buy an inverter & battery. My wattage usage are approx 300 - 350 . I want to run inverter around 10 hour/day. Plz suggest : 1) inverter VA & respective battery AH for above requirement.

    ReplyDelete
  21. Sir,
    I wanr to buy an inverter & battery. My wattage load is around 300 to 350 watt. Plz suggest Inverter VA & corresponding barrery AH to fulfil above requirement.

    ReplyDelete
  22. Hi .. Good day

    I have a question

    I have two banks of batteries and two battery chargers in parallel 48cvd

    and a total current of 35 amp, i thought that was going to of dividing the current in half

    but charger was left with 10 and one with 25 amps ...

    because that would happen?

    Thank you .. for your reply.

    ReplyDelete
  23. Hi .. Good day

    I have a question

    I have two banks of batteries and two battery chargers in parallel 48cvd

    and a total current of 35 amp, i thought that was going to of dividing the current in half

    but charger was left with 10 and one with 25 amps ...

    because that would happen?

    Thank you .. for your reply.

    ReplyDelete
  24. I really love reading and following your post as I find them extremely informative and interesting. This post is equally informative as well as interesting . Thank you for information you been putting on making your site such an interesting. I gave something for my information. Solar Charger

    ReplyDelete