Modernish Alkalines Very approximately - 9v (PP3) 500 mAH AAA 1050 mAH AA about 2250 mAH C 7500 mAH D 15000 mAH Values will be as little as half at high load and possibly somewhat better at very light or intermittent loads. Manufacturers provide some data. NiCds are about 20-25% of the above. Tjaart "I'm baaack" noted in 6/98 that a nominal 15AH cell gave 12AH at 300ma at 50 to 70 degrees F. Addressing the original question - Guess a grain of wheat runs at 1/2 watt (which may be wrong). 4 AAs will run it for 4 x 1.2V x 2.25 / 0.5 = about 20 hours - I would have guessed rather longer - maybe my power estimate is high. (1.2V mean voltage assumed). Russell McMahon -----Original Message----- From: A Rudzki To: PICLIST@MITVMA.MIT.EDU Date: Saturday, 24 July 1999 14:43 Subject: Re: battery life >>somebody wanted to know the life of AA batteries, >>I just came across it - >>An Alkaline AA cell has a capacity of about 2AH > > >2AH? I thought they were more like 750mAHs > >matbe thats NiCAD I'm thinking of..... > > >tony >