I have tried to disconnect the battery cable and that does keep the battery from discharging. But I am having some problems from time to time with my transmission shifting correctly. Right now it is fine and the transmission shop is telling me that by taking the power off of the computer that the computer may have to relearn my driving habits and shift points and may shift strange for 50 to 100 miles after being disconnected from power. This may or may not be happening. I thought I would add a charging circuit and try it a while and see if the transmission was happier.
Ken