Battery tenders on stored cars, do you leave em hooked up or disconnect first?

I see guys at the storage lot in Columbus just clip a tender to the battery and leave the car doors closed, but if the car has any parasitic draw from an alarm or a module, that tender is basically fighting a losing battle and cooking the battery over months, so am I the only one who disconnects the negative terminal before plugging in the tender or is that just overkill?

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kimr3315d ago

I used to just leave the tender hooked up and not think twice about it. But you mentioning the parasitic draw thing changed my mind. My Mustang has an aftermarket alarm that pulls power even when it's parked, and I caught the battery bubbling last winter. Now I pop the negative terminal off before I clip the tender on. Takes thirty seconds and saves the headache of a swollen battery.