Hi Jaime, yes Battery Tender is your solution for a car if not being driven more than 3 days.
My 986 has around 3 yrs old Bosch brand. After I was rear ended, the car was not driven for a month and the battery died. Did the jumper way to make it run. For a few days I keep using jumper cable to be able to drive the car and it will start again as long I start it again after an hour or hours but not overnight. So I was already planning of buying a new bosch battery and after searching where to buy, I ended up going to costco and pick up the Battery tender and that is around February. After few months of keeping the battery tender every time it is parked and last June for a 2 weeks vacation the battery tender is hooked. After that 2 weeks vacation, I no longer use the battery tender as long I drive the car no longer than 2 days (atleast start the car for a few minutes).
Meaning, my 3 yr old Bosch battery got totally drained for a month not being driven. And yes like others mentioned, 986 can drain the battery from alarm especially newer cars has a lot of electrical parts that uses the battery. Ex, alarm, auto defroster, etc.
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