What is the 2nd "auxillary" battery in the trunk for?
04-10-2007 | 04:52 PM
#1
Thread Starter
Three Wheelin'
Joined: Mar 2003
Posts: 1,402
Likes: 1
From: New Jersey
What is the 2nd "auxillary" battery in the trunk for?
Not sure if all Cayenne's have this- I noticed it mentioned last night in the owner's manual...maybe the manual answers my question in another section, but it was getting late & had to get up early for work 
04-10-2007 | 06:18 PM
#2
Racer
Joined: Mar 2004
Posts: 367
Likes: 0
Is that still listed as an option?
The auxiliary battery was standard on the 2003 and early 2004 Cayenne's before it became an option.
When you have the auxiliary battery the one under the driver's seat is used for electrical 'accessories' (it seems like that includes everything except the engine) and the auxiliary battery is isolated and only used to start the engine. This is all done via additional wiring etc. that is only present if you have the auxiliary battery installed from the factory
The auxiliary battery is actually in the spare tire wheel well either under a sub woofer or a spare tire. Contrary to what some dealers have told owners _two_ out of following _three_ items can coexist in the spare tire well: collapsible spare tire, sub woofer, auxiliary battery.
There are different sub woofers depending on if you're trying to coexist with a spare tire or the auxiliary battery.
I think it was ITC that noted Porsche started using a higher capacity battery under the driver's seat when the auxiliary battery wasn't standard any more. I can't verify this but I do know that I had the driver's battery replace recently and the new one didn't have a full charge when I brought the Cayenne in for another issue a few weeks later. Like many vehicles today it seems to take quite a bit of driving at above around town speeds to get the batteries charged completely. That includes a 30ish minute drive across town to the dealer.
On the tire storage front, please note that only the collapsible spare will fit in there. You can _not_ put a full size (flat or not) tire and wheel in the storage location. You need to leave your flat tire on the side of the road or carry tie downs to secure it properly in your vehicle and avoid being killed by it in an accident.
The auxiliary battery was standard on the 2003 and early 2004 Cayenne's before it became an option.
When you have the auxiliary battery the one under the driver's seat is used for electrical 'accessories' (it seems like that includes everything except the engine) and the auxiliary battery is isolated and only used to start the engine. This is all done via additional wiring etc. that is only present if you have the auxiliary battery installed from the factory
The auxiliary battery is actually in the spare tire wheel well either under a sub woofer or a spare tire. Contrary to what some dealers have told owners _two_ out of following _three_ items can coexist in the spare tire well: collapsible spare tire, sub woofer, auxiliary battery.
There are different sub woofers depending on if you're trying to coexist with a spare tire or the auxiliary battery.
I think it was ITC that noted Porsche started using a higher capacity battery under the driver's seat when the auxiliary battery wasn't standard any more. I can't verify this but I do know that I had the driver's battery replace recently and the new one didn't have a full charge when I brought the Cayenne in for another issue a few weeks later. Like many vehicles today it seems to take quite a bit of driving at above around town speeds to get the batteries charged completely. That includes a 30ish minute drive across town to the dealer.
On the tire storage front, please note that only the collapsible spare will fit in there. You can _not_ put a full size (flat or not) tire and wheel in the storage location. You need to leave your flat tire on the side of the road or carry tie downs to secure it properly in your vehicle and avoid being killed by it in an accident.
04-10-2007 | 08:20 PM
#3
Thread Starter
Three Wheelin'
Joined: Mar 2003
Posts: 1,402
Likes: 1
From: New Jersey
Thanks for the info- the problem with picking up a car on a Monday night is I don't have the weekend day to play with it and figure out all these things! I don't think we have the battery back there as it wasn't listed as an option on the window sticker- the manual didn't state whether it was standard or not.
On the battery front, yes today's batteries have much more demand placed on them. I had an old '78 911 that could sit for months in the winter and start right up in the spring. With the "newer" 911s (say 1990 and up) there is a small drain necessitating the use of the porsche charge o mat plugged into the cigarette lighter (or similar battery maintainer) if the car is to sit for a few weeks. I notice they now have the "charge-o-mat 2" in the brochure that came with my truck, but I don't really need it since the Cayenne is a daily driver.
On the battery front, yes today's batteries have much more demand placed on them. I had an old '78 911 that could sit for months in the winter and start right up in the spring. With the "newer" 911s (say 1990 and up) there is a small drain necessitating the use of the porsche charge o mat plugged into the cigarette lighter (or similar battery maintainer) if the car is to sit for a few weeks. I notice they now have the "charge-o-mat 2" in the brochure that came with my truck, but I don't really need it since the Cayenne is a daily driver.
04-11-2007 | 10:48 AM
#4
Pro
Joined: Mar 2006
Posts: 543
Likes: 2
don't worry.....
about the battery in the cayenne. mine has set for two weeks at a time without use and started right up. i still cannot believe, however, that they are using oldstyle batteries in this expensive of a vehicle.
