The lithium battery I have chosen shows constant voltage over the life of
the battery and drops suddenly (http://www.tadiran.com).  I know that each
year the battery will loose about 1% to 3% of its power.  So for a lithium
battery having 2100mAh rating, when calculating for 10 years, one should
make sure to take that into considiration. E.g. 2100mAh for 10 years (with
3% drain/year)  would have 1470mAh.  So the calculations should be made with
1470 not 2100.

But the voltage stays pretty much constant, doesn't it?

-----Original Message-----
From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On
Behalf Of Robert Rolf
Sent: Saturday, November 08, 2003 12:40 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [EE]: Testing prototype with a battery

Over 10 years the battery voltage will drop considerably (<2.4V is typical
EOL for Li).
What voltage you can run at will really determine your 'end of life'.
Yes, putting a parallel load that wastes 1000 times the power would be a way
to test your battery life in your lifetime, BUT batteries do NOT give linear
response to load. You always get more energy out of a battery by loading it
lightly. Think I squared R losses.

Robert

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