Originally Posted by Lordofthewings
Isn't the idea of the Ctek charger/conditioner that it stays connected all the time while the car is "winterised" or otherwise not being used ? (with the charger's brain figuring out when to come into operation). Since buying my Ctek that's how I have used it, mindful of the instructions in my (Roadster) manual which states: "If the vehicle is left standing for more than 1 week then it is advised that a battery conditioner is used to maintain the battery correctly". So which bits of the car's circuitry cause the battery to run down ? As far as I can tell there's just the clock and the blinking red light on the dash. On another car I use a similar charger and for the past 6 winters I have hooked it up to a standard domestic time switch which activates it for 3 hours each night -- the battery is still absolutely fine and presently shows 14.5 volts (which I don't quite understand, as it is a 12 volt battery).
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14.5v would be about the voltage of the charger when operating. But when the charger switches off, the battery volts dont instantly drop to 12.7. Instead there remains some surface change on the battery plates which keeps the voltage at 14.5 until there is a slight current drain and it drops back.