Well, I think you are right.
This is the situation we would use the discharge method. Tanks (T-54M and T55) have inside a little heater and to run the blower on the heater, after the engine is shut off, it takes battery power. When stuck out in the open, the boys would typically run the heater all night long to keep themselves warm and run the battery all the way down and bring it back for recharging. After the winter and many cycles of this, the battery would have hard time holding much charge and we would try to revive it by charging it and discharging with a small resistance (like a bulb) to rebuild the surface of the lead boards since this discharing was slow and nothing like the brutal drain from the heater blower in freezing temperatures. As I mentioned earlier, the method was fairly succesful, but hard data are not available to me - and probably to nobody else.
