charger madness

["Rhett T. George" <rtg@ee.duke.edu>]

 - Greetings -

David Dymaxion and Victor Tikhonov are both commenting on charging
efficiency in fairly correct terms.  One should observe that the
fully-charged cell contains a certain number of ampere-hours which
equates to a full charge measured in coulombs.  To recharge a cell
from which current has been drawn, the charging current must replace
the number of electrons (and their charge) which were removed in the
discharge process.  In recharging, current flows into the positive 
cell terminal and out the negative terminal.  This flow is measured 
in amperes which equate to coulombs per second.  For a fixed charging 
current, a fixed number of coulombs must flow each second.  This means 
a fixed number of electrons must flow into the cell each second.  How 
many electron?
	1 electron has a charge of (-) 1.6 x 10^-19 coulombs.
If a cell was very lightly discharged by the outward flow of 100 
electrons, then it can be returned to a fully-charged state with 
the replacement of 100 electrons (technically the charge found on
100 electrons).

The voltage which presents the electron to the cell determines its
energy (in joules, watt-seconds, or electron-volts).  The effect is
that more voltage leads to more energy.  Does the energy go into 
recharging the cell or into heating it?  It is at this point that
the folks who build batteries and those who build chargers are trying
to decide whether pulsing or continuous flow is better.

Stay tuned for the next development.

					Rhett George