This unit was constructed in
the shell of a Radio Shack battery charger. The original unit charged
only one type of battery at a time and only in pairs. This unit
allows for mix and match for AAA, AA, C, and D cells. Each battery
is individually monitored and charged. An LED for each one flashes
to show the current charging condition as follows....
- Dim with bright flash: No battery
detected
- Solid on: Battery charging
- Blinking on: Battery charged
When a battery is first inserted,
a small charge is pulsed to it. In between the pulses, the battery is
tested for voltage. This prevents the unit from attempting to charge
shorted or really dead batteries. If and when a voltage is detected,
the unit begins normal charging.
A somewhat complete schematic and what
appears to be the actual source
file are available. This unit was designed
some time ago.
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