As far as a battery discharging with a battery connected, but not plugged into AC, my thoughts on this is, that it would be hard to know if the battery was self discharging or a small current was flowing through the charging circuit.
I know DC chargers have a diode in the circuit, but is there any leakage through the diode?
Even if a battery is not connected to anything, most will self discharge.
I am sure some smart guy is going to take a meter and see if there is any flow with the battery charger not plugged in.
My thoughts is that a high dollar precision diode would not allow reverse current.
If the diode is not so good, then it may be possible for a small current to flow and n time would discharge the battery.
Alrighty now, just don't beat me up
Excerpt: Diode
The key function of an ideal diode is to control the direction of current-flow. Current passing through a diode can only go in one direction, called the forward direction. Current trying to flow the reverse direction is blocked. They are like the one-way valve of electronics.
If the voltage across a diode is negative, no current can flow, and the ideal diode looks like an open circuit. In such a situation, the diode is said to be off or reverse biased.
As long as the voltage across the diode is negative, it will t麹urn on and conduct current. Ideally, a diode would act like a short circuit (0V across it) if it was conducting current. When a diode is conducting current it is forward biased (electronics jargon for 逋サn?.