OK , I found that the capacity ratings for AAA , AA , C , D , and 9-V NiMH are 1000mAh , 2300mAh , 5000mAh , 8500mAh , 250mAh I have read about C ratings and read that most portable batteries are 1C meaning they draw a current equal to the rated capacity that takes one hour. For example 1000mAh AAA battery can deliver 1000mA for 1h if it had a 0.5C rating then it could deliver 2000mA for 30 minutes My question is Is this C-rating an approximate rating for the max amount of steady current that a battery can deliver per hours? Or for example in the case of AAA above could the battery supply 2000mA for 30 minutes even if the C-rating was 1C and not 0.5C because if this was the case then what would be the point of having this rating??? If it is away of approximating the max steady current for an hour then for the above batteries assuming 1C They would beable to deliver a max current of approximately 1000mA , 2300mA , 5000mA , 8500mA , 250mA for 1hour So all of these batteries even the 9-v NiMH can supply a device that draws 100mA for at least 2hours or more.... But if we had a device/load that drew 300mA then based on 1C rating the max the 9volt could supply steady current for is 250 for 1hour so this battery would not work for this load.... I also have looked up the internal resistance of the batteries and they are approx below at 100% fully charged or new values 9V zinc carbon 35ohm 9V lithium 16-18ohm 9V alkaline 1 to 2 ohms AA alkaline 0.15ohm AA NiMH 0.02ohm D alkaline 0.1ohm D-NiCad 0.009ohm D SLA 0.006ohm AC13 zinc-air 5ohm 76 silver 10ohm 657mecury 10ohm So for a AA alkaline which was 2300mAh with 1C => it can deliver 2300mA for 1hour. Going by the internal reistance and the nominal voltage rating we have by ohms law => 1.5volt/0.15ohm = 10amps => 10,000mA So why the difference 10000mA to 2300mA that is nearly 5 times less then the theoritical ohms calculation .... So I guess I am wondering if a AA with the above ratings can only supply steady max current of 2300mA for 1hour but with if it wasn't supply steady current it could supply more then 2300mA and a max of 10,000mA if shorted.... (minus wire resistance) Just trying to piece this stuff together I know a more exact model is Peurkert's equation but it is hard to work with this all the time so maybe internal resistance , mAhours , and C-rating is a better thing to use for approximation??? Thanks for clearing an or this up.