(ET) Charger not so bad

[Rhett George <rtg ee duke edu>]

 - Greetings -

Thanks to Tim for alerting all to the posibility of a charger with one
or more degraded (corroded) connections that will not pull the battery 
voltage up enough to fully recharge.  Tim is correct also in that this 
should be done with a load, i.e., batteries connected.

The ferroresonant transformer flat-tops the voltage waveform on the out-
put.  With no load, the voltage dips to 0 V 120 times a second (on 60
Hz) and rises with a sinusoidal slope to the flattened top in between.
The ol' voltmeter tries to make some DC sense of this and settles for 
a value such as 38 or 39 V.  With the batteries connectedd, there is 
no dip to 0 V.  The charger bumps up the battery voltage to something 
a bit over 43 V during the flat-top pulse.  Voltage drops back during 
the low voltage part of the transformer output.  The meter finds the 
average to be 43 V when all else is correct.

Keep on 'Trakin.
                                        Rhett