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I am so disgusted. I have owned a beautiful Z3 for over 1 year- seldomly use it, have replaced the battery twice. Something is draining the battery. Am I supposed to start it daily? Anyone have any ideas? Thanks.
 

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There seems to be a lot of thing in the Z3 that draw power even while it is just sitting. Many people who don't drive their cars a lot have a battery tender to keep the battery healthy. I usually drive mine at least a couple of times a week, but the past few months have just dumped snow on Denver and there was about 6 or 7 weeks I couldn't get it out. When I first started it after the snow melted it just did turn over and start. I would guess that any time it sits for a couple of weeks or longer, it would be a good idea to have a battery tender attached.

Ken
 

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Put a an ammeter or multi-testor between the positive battery cable and the positive post of the battery set on amps. Disable the trunk light. (I propped my trunk open with a screwdriver that poked in the switch for the light.)

You should see <50 milli-amps being pulled at rest with nothing on. (It takes a few minutes to go into rest mode.)

If you see more, pull fuses one a time until it drops. This isolates your circuit. Then whip out the trusty wiring diagram and determine what that fuse feeds. You can unplug components one at a time.

Mine was a bad sub amp. The antennae base was leaking water on it and shorted it such that it was on all the time.

If you are pulling <50 mili-amps at rest......Drive the car every once and while. The Z3 was built to be driven!!!! :p
 

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I know on the 7 you can switch the batt to off in the trunk and it only allows power to go to things that need to be powered... you might have the same switch.
 

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I've been meaning to post this for about 6 months...

On the subject of battery tenders, you might want to look at the CTEK 3300. I think a cigarette lighter adapter is available, it is on the Porsche branded version. Pretty easy to wire anything you want plug-wise to it.

<img src="http://www.autosportcatalog.com/file_center/files/ctek/ctek1-big.jpg">

<img src="http://www.autosportcatalog.com/file_center/files/ctek/ctek2-big.jpg">
 

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I am so disgusted. I have owned a beautiful Z3 for over 1 year- seldomly use it, have replaced the battery twice. Something is draining the battery. Am I supposed to start it daily? Anyone have any ideas? Thanks.
I had a battery drain problem that turned out to be a short in the power seat switch on the passenger side. Dealer found the problem, which was intermittent, and replaced the switch.
 
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