zedudemeister

Perhaps someone out there can explain this to me in simple terms.

I have just bought a 2003 Cayenne. The other day the car wouldn't turn over. I jump charged it from the charging terminals and it started ok. I looked round the engine and the boot and wondered where the hell the battery was. I couldn't find it, so for expediency sake just attached a battery manager to the charging points and left it for two days to charge up.

Two days later the display on the charger shows it's still charging and not "maintaining" the battery.

I have since discovered through this great forum that my car has two batteries. One under the car seat that looks like a bastard to change and one under the bose subwoofer.

My questions are these

Which battery provides the power to start the car?

If I'm charging the battery through the terminals under the bonnet is it charging up both batteries?

If it doesn't which battery is it charging ? under carseat or under subwoofer?

If the battery under the subwoofer isn't getting charged do it need to remove the subwoofer and charge that one independently of the other one.

The charger i'm using should be powerful enough # Suitable for all types of 12V lead-acid batteries (inc. MF, GEL and AGM)
# Charges batteries up to 150Ah
# Maintains and conditions batteries up to 225Ah

Are my batteries just shagged and should I just swallow it and get them replaced?

Help much appreciated.
Cheers

wirunner

They may be original batteries so probably a safe bet to replace both given the age. In the case of two batteries on original alpha/beta models, I believe the rear one starts the car when using the main key fobs. The owners manual can show you how to access both batteries to replace them - not that hard. You've probably already spent more time just thinking about it than it would take to replace them.

zedudemeister

Cheers, you're right. Once to you get at it, providing you have the right tool to remove those seat floor bolts it is a piece a cake.

hk_usp9f

You'll need a 10mm triple square bit for the seat floor bolts. Not easy to find at your corner hardware store; it's best to order one online before you need it.

richc

What does a 10mm triple square bit look like? I Googled it - if what I found is correct, it's a Torx bits but with 12 points instead of 6...WOW. NAPA reportedly has them,
10mm - SER2305 - $5.49

zedudemeister

yep that's right.

and if some idiot has got to it before you and broken the teeth on the head of those screws you can hammer in a 10mil normal allen key and it will work as well.

neccessity is the mother of all invention.

wirunner

You can also carefully use a T45

hk_usp9f

Yep, its the one with 12 points. I looked at the one Napa has - it should work but the one I got has a 1/2 inch square drive.


Funny how Napa calls it a "serrated wrench" in their online catalog.

As I've said before, it is best to get one before you actually need it. In my case the idea crossed my mind when, for personal reasons, I was unable to drive mine for a few months and was afraid that the battery died in the meantime (it didn't). Looking at what I had to do in case I had to replace the battery the first obstacle was figuring out what tool would loosen that odd-looking bolt.

richc

Been there, done that - many times.

Zba

zedudemeister, if the main battery under the seat cannot provide sufficient power to start the car, turn the key all the way to the left then start again. Turning the key to the left activates the secondary battery which is only used for starting when the main battery is dead. You can witness this by watching the voltmeter. If the secondary battery is dead, get some jumper cables!