Battery disconnecting? Any issues long term? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

koosh · 12-20-2013, 03:02 PM

Just wondering if there is anything I need to watch out for if I disconnect the battery on the boxster for any length of time?
Will the alarm go off when I reconnect it?
Will the electric windows need reset afterwards?
I don't have the OE stereo so I don't need the code!
Is there anything else I should watch out for?

epapp · 12-20-2013, 03:18 PM

Dont forget to reset the clocks

What year is it?

Joe B · 12-20-2013, 06:50 PM

No issues on my 2003, except, don't close the frunk!

Steve Tinker · 12-20-2013, 08:37 PM

After you have disconnected the battery, you will have to initiate the base settings of the injection system as follows:
1) Connect battery.
2) Switch on ignition - all dash lights on ( but don't start engine) for +/- a minute.
3) Switch off ignition + remove key for 10-15 seconds.
4) Start car as normal.
5) You will now have to reset the electric windows / clock etc.

nieuwhzn · 12-20-2013, 08:49 PM

Well, your injection maps will be reset to the original default maps. Depending on the degradation in your system (MAF, injectors, etc) the maps that your were running before could have seriously wandered off. Resetting to the default maps could result in your car initially idling and running like crap. You have to put a couple of hundred miles on it to get your maps rebuild.

Christian H · 12-20-2013, 10:57 PM

Quote:

Originally Posted by koosh

Just wondering if there is anything I need to watch out for if I disconnect the battery on the boxster for any length of time?
Will the alarm go off when I reconnect it?
Will the electric windows need reset afterwards?
I don't have the OE stereo so I don't need the code!
Is there anything else I should watch out for?

On UK spec cars you need to turn the ignition on (idiot lights illuminated) before the battery is disconnected otherwise the alarm will sound with your head above it!
Guess how I know?
Also leave ignition on for reconnecting for the same reason.

koosh · 12-20-2013, 11:23 PM

Ok those are good tips guys thanks!
I didn't know if there was any things like ecu maps or that but this has confirmed it! Some of my old cars had this and some didn't so? And things like leaving the front and rear lids open I wouldn't have thought about either hahah!
Car is 2001 UK spec for clarification

Steve Tinker · 12-20-2013, 11:36 PM

Quote:

Originally Posted by nieuwhzn

Resetting to the default maps could result in your car initially idling and running like crap. You have to put a couple of hundred miles on it to get your maps rebuild.

It's not the miles that "resets" the maps but the quantity of completed heat cycles - cold start up to full running temperature down to ambient again.
It usually takes 3 or 4 cycles from disconnecting the battery for the ECU to revert back to stock settings. Using the procedure as I described above quickens the effect without the car running poorly for a few days.

Joe B · 12-21-2013, 01:52 PM

Quote:

Originally Posted by Steve Tinker

After you have disconnected the battery, you will have to initiate the base settings of the injection system as follows:
1) Connect battery.
2) Switch on ignition - all dash lights on ( but don't start engine) for +/- a minute.
3) Switch off ignition + remove key for 10-15 seconds.
4) Start car as normal.
5) You will now have to reset the electric windows / clock etc.

I didn't have to do any of that (except the clock of course) and it ran fine as soon as I started it up...

kjc2050 · 12-21-2013, 02:33 PM

Quote:

Originally Posted by Joe B

I didn't have to do any of that (except the clock of course) and it ran fine as soon as I started it up...

That's been my experience as well. Battery was out for 4 months, put it back in, turned the key and started it, no issues, ran great.

ilikeching · 12-21-2013, 03:22 PM

Just remember disconect minus- first and + , then vice versa when connecting.+ to -
.

boxster · 12-21-2013, 10:30 PM

Mine is a 99. Since its not my daily drive and i hardly use it, i put a switch on the negative connector to the battery. Sometimes its even disconnected for a month, and when i connect it back again car starts immediately without any problems. My routine is to leave the driver's side window down a bit just in case i want to open the door whilst the battery is disconnected, and the front trunk unlocked.