Battery in / Battery out

[Psoncanada]

I get all confused info as to if I can remove my 993 TT battery when putting her away, or not. Some claim that it can screw around with all the systems, but most people seem to claim that the only effect is that you have to put in the radio key when putting the battery back in the spring? I also have heard that the first 20 minutes or so she might be unreliable in the spring while the engine is finding it's "settings", something I could live with. Reason for the question is that the garage owner doesn't allow batteries in due to the fire hazard. Comments?

[Bartruff1]

I get all confused info as to if I can remove my 993 TT battery when putting her away, or not. Some claim that it can screw around with all the systems, but most people seem to claim that the only effect is that you have to put in the radio key when putting the battery back in the spring? I also have heard that the first 20 minutes or so she might be unreliable in the spring while the engine is finding it's "settings", something I could live with. Reason for the question is that the garage owner doesn't allow batteries in due to the fire hazard. Comments?

I just stored my 97 993 C2 and I disconnected the negative battery cable.....since I didn't know what might happen, after a few days, I reconnected it and the car started and ran as usual ???

[Psoncanada]

Thanks - as I said there seems to be more than one school. But most people seem to have disconnected without problems...

[JFP in PA]

Actually, this a more complicated subject than you might imagine……. Excellence magazine recently ran an interesting article on why you really should not disconnect the battery without an alternative supply source connected, such as a battery maintainer that has this capability (not all do, most actually stop the current as soon as it sense the battery disconnect such as during a battery replacement). Problems caused differ with model and year, but range from the annoying, such as the DME resetting and causing rough idle and poor running until it relearns; to real head aches like having the gas gauge lose calibration, which requires a PIWIS and draining the tank to reset……………

[Bartruff1]

My owners manual on page 117 " Storing...." under " Electric" it sez " The battery should be removed...." soooo... to me, disconnecting the battery should have the same effect... the owners manual on page 131 " Battery " it sez " when the battery is reconnected the engine must be run for ten minutes to allow the control unit to re-aquire data.... during this period the engine may idle unevenly...".... I'll find out this spring...

[Psoncanada]

My owners manual on page 117 " Storing...." under " Electric" it sez " The battery should be removed...." soooo... to me, disconnecting the battery should have the same effect... the owners manual on page 131 " Battery " it sez " when the battery is reconnected the engine must be run for ten minutes to allow the control unit to re-aquire data.... during this period the engine may idle unevenly...".... I'll find out this spring...

I'll go with that - even though the Excellence article makes one nervous! Thanks!!

[JFP in PA]

Not all model and/or year combinations are prone to having problems when the battery is disconnected; only issue is that there is no definitive list of which ones to be concerned about, you get find out by disconnecting it (thank you, Porsche). The last thing I need is to have a car come into the shop because the battery is crapping out, and end up creating a couple of hours of unpaid labor over a simple battery swap that should have been done in 20 min., or a customer that leaves unhappy with a temporarily poor running car, or later discovers his gas gauge doesn't work anymore. So we always use a maintainer with a supply mode when we disconnect the battery……………….