Wonky electronics

[alland]

Returned home after being away for 2 weeks and discovered that the cayenne's battery was completely discharged. No problelm just put the battery charger on and situation should be remedied. Not so... when I hooked up my charger (on the 11 amp setting) all the electronic systems in the car go wonky. The headlights randomly go on and off, sometime blinking from side to side, the nav screen attempts to come on in a distorted staticy way, and warning lights blink on and off. I disconnected the charger after a few minutes as things were not stabilizing. Anyone have any idea what would cause this or potential solutions?

[DUTCH VanAtlanta]

Responded on the other forum.

[wvicary]

Turn off all electrics when charging the battery. It could take several hours charging to recover if it's been completely discharged.

[alland]

Turn off all electrics when charging the battery. It could take several hours charging to recover if it's been completely discharged.

That's what makes this so "wonky", everything is off. The wierdness starts as soon as I connect the charger. Ignition and lights are all turned off.

[Loren]

Then take the battery out of the circuit to charge it (disconnect the cables to the car).

[odix]

Also use a CTEK or Porsche (which is a CTEK) charger/conditioner -- it cycles the battery in a few specific phases and takes over 14 hours to condition/charge your battery and you should be set if your battery is OK and does not need to be replaced. I run the sequence once a month year round.

Also, Loren's note is key -- in your case, deal with the battery directly, off the vehicle's grid. Flip the driver's seat up and you're set to access the battery. The 2004 Cayenne owner's manual has directions on how to access the battery. You can download the manual here on Renntech.

[alland]

Thanks guys, I'll let you know how it goes

[alland]

looks like the bolts that have to be removed to tip the seat back are rather large torx heads. If so I'm going to have to make a trip to the hardware store as my torx heads are not big enough to fit. I'll let you know how things develop.

[alland]

Problem seems to have been resolved. In order to get the seat back to disconnect the battery cables, I needed to supply power using jumper cables. Although the car would not start when I connected the cables, all the blinking and stuttering electrics did settle down. I left the cables on for about 10 minutes and when, as an experiment, I re-tried the starter it worked. took her out for a half -hour drive and when I turned her off she was still able to re-start on her own. I'm thinking my battery charger may have been at least part of the problem but it had always worked before??/

[wvicary]

You can not fully charge the battery on a short road test. I suggest you charge the battery for 12+ hours and have it load tested. These vehicles are known to reduce the service life of batteries and invest in a maintainer.

[RFM]

The CTEC device is able to charge the battery for more than 95%, the car alternator in optimal condition and circumstances only 85%, enough for regular use but problematic after long standstill, given the considerable decrease of power when not in use. A CTEC or similar device is recommended in your case.

[alland]

RFM,

Thanks for you advice. To further complicate things, I'll be putting the CTT away next week until next winter. I will have it on a trickle charger but am wondeing now whether I chould have the CTEC charge before or after storage. I'm leaning towards the latter. Any reason to do it now?

Allan

[RFM]

The CTEK (same as Porsche) can be used the year around without problems, once the battery is fully charged, the device goes automatically, alternately from maintain to trickle charge function as needed.

[lowell]

Also use a CTEK or Porsche (which is a CTEK) charger/conditioner -- it cycles the battery in a few specific phases and takes over 14 hours to condition/charge your battery and you should be set if your battery is OK and does not need to be replaced. I run the sequence once a month year round.

Odix,

I saw that the Porsche one uses a cigarette lighter connection to eliminate the need to access the battery. Will this work the same (and as well) and what you're doing? Also, our Cayenne is being used for weekend family travel mostly, with occasional short trips during the week. Would you recommend I do the same as you and use a charger once a month - or am I driving enough to not need it?

[odix]

Hi -- I bought the CTEK model 3300 ($70) at crutchfield.com. For $10 more you can purchase the cigarette adapter -- then you will have exactly the Porsche OEM version and can charge your battery (one or two if you have that option) via the cig adapter. Some people purchase an adapter for each vehicle they own and leave the adapters plugged-in.

Our Cayenne S is mostly a daily driver but often it's stop and start in heavy traffic using the radio, AC, lights and electronics -- not a lot of time spent at high speed/freeway RPMs which is key for battery charging. My monthly routine may be overkill but it's so easy I just do it and it may be extending our battery life. Once I'm in our garage I crack a window (passenger door), plug it in one of the cig adapter jacks under the glove compartment and am good to go.

I also do this for our VW GTI, my mother-in-law's X5, etc. Can't hurt. I always plug it in the Cayenne if we travel and are away for more than a few days when I know it will sit unused. The CTEK's cycle off and on and will not damage the battery -- unlike some trickle chargers which can cause damage.

One note, I always keep the unit itself on our cement garage floor -- it gets hot and I do not want anything too warm left in the vehicle. The cord is long-enough to go from the cig adapter out of the window to the CTEK unit on the floor, then the unit plugs into the wall or a heavy-duty extension cord. Sequence is this: 1. plug CTEK into car, 2. plug CTEK into wall current, 3. turn CTEK unit on. The LEDs will go from red to green to let you know the cycle is complete.

And as Loren and others have noted, it's hot weather that really strains batteries, not just cold.

A really helpful use of the CTEK unit is sometimes when I'm in the Cayenne with the engine off experimenting with settings or radio pre-sets or whatever I have the CTEK plugged in so I don't drain the battery. And when the time comes to physically change your current battery(s) for a new one keep the CTEK plugged-in so all your settings are not lost.

Attached are pics.

Edited March 30, 2010 by odix