you wont get anywhere near 10-13 days, it will probably stop after a day or two depending on weather. you see its not the current that it measures, the devices itself cant know what its drawing power from so cant know when its running low, instead it measures voltage droop, which can be effected by the weather and other devices within the car that are still drawing power (lots of computers wont turn off for quite a while, opening doors can turn on these computers, hell even some cars with keyless systems can turn on if you walk nearby it!) basically, once the volts drop to below a defined value, it cuts off completely and wont turn on until you turn on the ignition. ive set mine to 11.9v
That will prevent your battery from completely discharging which I think is what you were asking!
its pretty handy really, I have never had any issues at all with it, ive entered the car and its been off and the car starts just fine, ive even been sitting in the car when it turned off once, she comes out with a wee message about the battery and the system is about to turn off