What does 10-hr AH means?

Discussion in 'The Projects Forum' started by Lightfire, Mar 17, 2011.

  1. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    Hello, please refer to this link:

    http://motolite.com/battery.php?id=20

    Go to info and find 10-hr Ah category.

    And what does it mean if the 10-hr Ah is rated as 2, 9 and so so on..................
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    I believe it refers to 10 hour dischcrge time to yield rated AH capacity.
     
    Last edited: Mar 17, 2011
  3. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    1 AH, One amp for one hour from a battery.

    The number is misused a lot though. If you exceed the current capacity of the battery the measurement goes out the window, and the battery is likely damaged or distroyed.
     
  4. kasamiko

    New Member

    Dec 15, 2004
    2
    0
    This means that a lead-acid battery rated for (for a 10-hour rate) 10-hr 200 Ah will deliver 20 amperes of current for 10 hours under standard temperature conditions..
     
  5. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    The discharge rate has to be stated because, even if you avoid excessive discharge rates, the effective Ampere Hour capacity is a function of the load. Typically, a somewhat bigger capacity is obtained by discharging a battery more slowly, say at a 20 hour rate instead of a 10 hour rate. At extremely low discharge rates of perhaps hundreds of hours or more, self-discharge may become significant and the Ampere Hour capacity will be lower.

    Let's take an example. If your 2 Ampere Hour battery were discharging at a 10 hour rate, it would deliver 2AH over 10 Hours, so the load current would have to be 2AH/10H = 0.2A. If the load current were half as much (0.1A), the battery might just hold out for a little longer than 20 Hours. If the load current were increased to 0.4A, the battery would almost certainly last less than 5 Hours.

    The message to take from this is that battery capacity needs to be related to the size of the load. A battery must not be too small or it will discharge too quickly and so give a disappointing capacity. In the limit, as has already been mentioned, it could be ruined. Equally, there is little point in having a huge battery to supply a tiny load, because the self- discharge would become dominant.
     
    Last edited: Mar 17, 2011
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