What is mAH?

Discussion in 'General Electronics Chat' started by nancycosta222, Dec 11, 2009.

  1. nancycosta222

    Thread Starter New Member

    Dec 10, 2009
    Hi guys
    First of all i have to inform you that i am specially from the management guy and now want to know about some electronics stuff for my daily life......so help me.....
    my question here is what's the mAH exactly in terms of the general electronics batteries specifications.....please give me answer in terms of technical fundas, dont's share all your practicals theories and all that.....because i have to know this is just only for to recognize what type battery with the specification i have to used now.......and for the changing of it what type of quality needed in terms of that......!
    Thanks for reading this much ......:)
  2. Rick Martin

    Active Member

    Jun 14, 2009
    It is how many milli amps it can supply for 1 hour. mA (milli amps) per H (hour) in total. Ie 500mAH means it can supply 500mA for 1 hour.
  3. Wendy


    Mar 24, 2008
    milli is 1/1000, so 500mAH is .5AH. It is possible to run into the latter abbriviation too.
  4. Rick Martin

    Active Member

    Jun 14, 2009
    Yes, this is very true.
  5. steveb

    Senior Member

    Jul 3, 2008
    mAH , or AH are measures of the total electrical charge that you can take out of the battery under nominal conditions. The larger this number, the longer the battery will last. Keep in mind that different battery types behave differently under high a low loading. So the application can also affect the decisions you make about the battery type. In other words, you will not get the full rated capacity if you use it in a power hungry device, and some batteries may be much better at giving you capacity closer to the ratings than others, in those cases.

    If you take the AH rating times the battery voltage rating (in Volts) you will get WH (Watt hours), which is a measure of energy.

    If you then divide the WH rating by 1000 you get kWH (kiloWatt hours) which is also a measure of energy. You may notice on your electric bill that you are charged by the kWH. So, you can actually estimate the cost of the energy in the battery and compare it to the cost of electricity you use in your home.

    For example, a 2000 mAH battery at 1.25 V will give you an energy as follows:

    2000 mAH /1000 = 2 AH
    2AH x 1.25 V = 2.5 WH
    2.5 WH /1000 = 0.0025 kWH

    Being that you are a manager. Let's talk in your language a little. :)

    Note that 0.0025 kWH would cost you less than 0.05 cents from the electric company ! If you consider a rechargeable battery, the cost of the electricity to charge it may be 0.1 cents due to inefficiency. If you charge this battery 1000 times (which is its expected useful life maybe), it will cost you $1 in energy. That's cheaper than the battery cost in the first place.

    Anyway, with a little math you can figure out the cost of energy and make comparisons between powering with batteries or home AC power. You can compare the value of rechargeables compared to single-use types. You can compare to see if the cost of alkaline batteries is worth it compared to the cheaper carbon batteries, etc.

    Of course, cost isn't the only issue. You can also estimate how long a battery will last. A 1000 mAH battery will only last half as long as a 2000 mAH battery. A 2.5 WH energy will power a 250 mW device for 10 hours, etc.....
  6. someonesdad

    Senior Member

    Jul 7, 2009
    I keep a shell script on my system to print out battery info on my screen. It's culled from various sources. If you have more information to add to it or update it, please post!
    Code ( (Unknown Language)):
    2. Battery capacity in mA*hr
    4.                 Alkaline    C-Zn    NiCd        NiMH        Lithium
    5.                 --------    ----    --------    ---------   -------
    6. AA               2700       1100    600-1000    1700-2900     3000
    7. AAA              1200        540                800-1000
    8. AAAA              625
    9. C                8000       3800                4500-6000
    10. D               19500       8000                900-11500
    11. 9 volt            565        400    120         175           1200
    12. CR123                                                         1500
    13. CR2025   dia=0.787, height=0.098                               160
    14. CR2032   dia=0.787, height=0.126                               225
    15. CR2450   dia=0.965, height=0.197                               610
    18. Silver Oxide   Volts mA*hr     Alkaline  Volts  mA*hr   Dia, in   Height, in
    19. ------------   ----- -----     --------  -----  -----   -------   ----------
    20.     SR41        1.55   42        LR41      1.5    32     0.311      0.142
    21.     SR44        1.55  200        LR44      1.5   150     0.457      0.213
  7. Duane P Wetick

    Active Member

    Apr 23, 2009
    You can probably appreciate this little excercise we did long ago when I was a student. We took all the best AA cells that were on the market; Duracell, Eveready, Energizer, Radio Shack and several off brands including some Ni-Cads too. We put a dummy load on each of the batteries and carefully monitored the discharge characteristics on a chart recorder. We ran all tests several times to get some repeatable data. We found that the least expensive batteries, (Radio Shack) provided the best mA discharge/ time ratio for each cent of cost. No other battery was even close.

    Cheers, DPW [ Always remember that you are not going to live forever.]
    Last edited: Dec 14, 2009
  8. ke5nnt

    Active Member

    Mar 1, 2009
    It's depressing to think Radio Shack has the best of anything...
  9. Rick Martin

    Active Member

    Jun 14, 2009
    It is surprising how often a lesser or what is regarded as inferior brand turns out to be a much better buy than the leading marketed brands.
  10. nancycosta222

    Thread Starter New Member

    Dec 10, 2009
    Thanks to all buddies to this share this much healthy technical stuff here....
    now got it.....the way...what's exactly the mean of that...
    thanks agian.....!
  11. nancycosta222

    Thread Starter New Member

    Dec 10, 2009
    hey bro........thanks for this much information....but the exactly what's this.....i can't understand.....
  12. smanches

    New Member

    Mar 27, 2009
    Strange nobody has mentioned a VERY important point.

    The Ah rating of a battery is based on a very specific discharge rate. If you discharge the batteries faster than this, you will get less energy out of them. If you discharge slower than this rate, the battery will last a little longer.

    The discharge rates are usually based an a 10 or 20 hour discharge rate. That is, if you had a battery that is 20Ah rated at the 20 hour rate, it means you can draw 1A per hour for 20 hours. If you pull more current, the battery will not last as long. If you pull less current, it will last a little longer. The curve is exponential I believe (or close to it.) If you pull twice as much, you'll get less than half of the actual capacity.
  13. peranders

    Well-Known Member

    May 21, 2007
    Different battery types have different capacity. let's say you have a device which consumes 10 mA. With an AA cell you will have power for 270 hours.