Did you READ what I wrote? I said that static voltage before starting is irrelevant, and that available voltage during the start procedure is what counts. Many batteries will show a "full" charge, but cannot start the engine. A static battery should not have more than 12 and a bit volts. A running engine will show around 14V at the battery because that is what the alternator's regulator is controlling it to. And the reason the voltage is around 14V is so that the chemical reaction that produces the static voltage in the first place actually "runs" in reverse.mad082, the battery is supporting an alarm, a radio with battery backup, and a clock with battery backup. All these act to drain the available voltage from the battery. (And the battery is a few years old now, admittedly)
Apparently the secret to not blowing things up is to switch the parking lights on before disconnecting jump leads. That way, some of the excess current being generated by the alternator has somewhere to go, other than to the jumping battery, which suddenly "disappears" from the circuit.