When the key is in the ignition, a lot of stuff (computer, control modules, maybe radio amp) stay powered. Enough load to drain the battery overnight, apparently.

 

That is what I thought. Does this happen a lot ? First time in three years I have done this. Seems absurd, killing the battery this fast.

 

I've done this a few times to my 987 when it's on the lift.. Not good for you battery but as long as you don't do it too often it's not a big deal.

 

Read the FAQ. Documented in 2007. 1.7 amp draw http://www.planet-9.com/faq.php?faq=techdata#faq_batterysp

 

Thanks for the link. Exactly what I was looking for. I mostly wanted to be sure this was normal and not a problem with my particular car.

 

Dealing with a dead battery in a Cayman is a real pain. A trickle charger is a must, at least in the winter, if you're in an area that gets below 32 degrees. An inexpensive one works fine.

 

Just bought one. Now I have to decide where to run the wires.

Well assuming overnight is about 12 hrs; 1.7A x 12 hrs = 20.4 AH. So if the battery went "dead" it was not in the best of shape in the first place. BTW the battery really does not go "dead". The battery voltage drops below the level where the electronics will function so they just go out so to speak. Old cars, without electronics, would turn over although slowly and might just fire. If not, one could just push them and dump the clutch to turn over the engine which would fire up. Now that is no longer possible. Anyway you can see that at 1.7A you only have so many hours before your 120AH - 150AH battery is drawn down.

Probably 16 hours, maybe more. Now I have an air bag light to turn off.

 

Well assuming overnight is about 12 hrs; 1.7A x 12 hrs = 20.4 AH. So if the battery went "dead" it was not in the best of shape in the first place. BTW the battery really does not go "dead". The battery voltage drops below the level where the electronics will function so they just go out so to speak. Old cars, without electronics, would turn over although slowly and might just fire. If not, one could just push them and dump the clutch to turn over the engine which would fire up. Now that is no longer possible. Anyway you can see that at 1.7A you only have so many hours before your 120AH - 150AH battery is drawn down.

 

I got one of these along with the battery tender, and it works extremely well. I use the outlet for the cig lighter in the center. https://smile.amazon.com/Battery-Te...Q6VB49EZN6SDKRNM&pd_rd_w=vWOiX&pd_rd_wg=1JWgQ&psc=1&refRID=1064Q6VB49EZN6SDKRNM

 

Now I have to decide where to run the wires.

From experience (not with this car - yet) - Get the cigarette lighter adapter, plug it into the center console and run the wire across the drivers seat (maybe even loop it through the steering wheel)... I have a friend who goes to the extent of running the wire through the ring on his key chain...

 

At the base of the windshield where the fender meets the corner of the hood there is a removable cover .It pops out easy. I took the battery cover off and the plastic trim next to it. I pushed the wires from the hole at the base of the windshield and over to the battery . Hooked them up and replaced the covers. Now I just have to pop the little cover and I can hook up a charger. Invisible, no drilling and easy. I may post up a pic later.

 

I hope to never need it. It is there just in case. I drive my car almost every day so the battery should stay up.

 

Pic.