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Deep Cycle Replacement Battery

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Cayennes and Touaregs with a single battery and lots of accessories seem to have a major battery drainage issue. Has anyone found a deep cycle battery that will fit under the driver's seat?

Optima does not make one that is "short" enough. Their yellow top would be perfect.

Thanks in advance!

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Why not just buy a high quality replacement battery for the OEM. Putting one under the driver's seat does not sould very safe in the unlikely event of an accident.

:jump: uuummm you do realize the battery is under the drivers seat from the factory right?

Edited by gixxer1127
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You have to rise the seat, remove the 2 bolts on the front of the seat base, remove the left and right trim on the back of the seat base, remove the screw which hold the heater/airco vent under the seat and remove the vent, open the battery cover on the front and the rear, tilt the complete seat to the back and remove the cover, remove the battery.

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The seat can be just unbolted and pushed onto the rear seat. I leave the electrics hooked to the seat then I never worry about loosing any settings. After the seat is out of the way you must remove the lower seat mount and then the battery is under a plastic cover containing a integral vent. It's very straight forward to replace just a little more work then normal. I also use a memory saver hooked to the battery jumping points under the drivers trim panel located under the front hood.

Make sure to remove the ignition key... don't leave it in as it can power up accessories.

I believe there is also a TSB on the alternator wiring harness for the V8's that cause intermittent charging problems.

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There is no room under the hood and under the back seat neither, the gas tank forms a copy of the rear bottom of the car. The firs year after the introduction you could have a second battery in option which was located in the spare wheel housing, on Cayenne's without BOSE.

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When the Cayenne first came out 5 years ago the local dealership had a tech session. As a Boxster owner I did not pay much attention. Don't remember which version it was.

But I remember it had 2 batteries, and 1 was under the seat. The second picture I think is the battery where the spare would go.



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I have been unable to find an alternate battery to OEM. The height is the issue. Optima batteries can be placed on their side, but none are narrow enough to fit.

It seems that owners with only one battery must be patient. They should at least ensure that all related TSBs are done. If part of a TSB, the replacement battery is free. Also, keep an eye on your ampmeter. It should read 14VDC while the engine is running.

I have learned to use a trickle charger or solar charger (away from 110VAC) in the winter. I may still get annoying idiot lights, but I can still start the thing.

Regarding parking valets, I have installed an under-dash switch to deactivate my keyless start. With it on, removing the key will not "power down" the electronics. Big drain fast. Even techs have problems with using the button.

Ciao for now

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