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In the engine compartment there is a charging positive and negative terminal under the small plastic cover on the left rear of the compartment (LH Drive at least). Pop the cover and there is a Ground post and just to the rear of it there is a Red plastic flip cover you flip up to reveal the Positive terminal. If you have time I would slow charge it with a 2~4 amp charger at least over night if not upwards of two days. If your in a hurry faster charge it with 6~8amps but use a quality charger with Automatic overcharge protection. If the battery is new and Ok then you shouldn't be getting that warning unless you were running some accessories with the engine off for a while. You should still be able to start it with that warning although it is harder on your Alternator to do all of the charging of the battery and a normal load, and it is an expensive Alternator so why put the extra stress on it.

There are some details that I am assuming, battery condition and such. It could be a bad battery, a parasitic drain larger than normal ( Cayenne does have a lot of Parasitic drain, I keep mine on a battery tender if I'm not driving it for a few days), bad Alternator/voltage regulator, dirty connections (Ground and/or Positive lead), etc....

Edited by hahnmgh63
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  • 2 weeks later...

do you mean I can charge it through the jumpstart terminals?

The challenge I have is that the place the car is parked has no AC power outlet. (Idon't have any garage in my flat in Hong Kong)

do you think I can use a fully charged portable jumpstarter to charge the battery through the jumpstart terminals at the engine compartment?

Any advice is much appreciated.

In the engine compartment there is a charging positive and negative terminal under the small plastic cover on the left rear of the compartment (LH Drive at least). Pop the cover and there is a Ground post and just to the rear of it there is a Red plastic flip cover you flip up to reveal the Positive terminal. If you have time I would slow charge it with a 2~4 amp charger at least over night if not upwards of two days. If your in a hurry faster charge it with 6~8amps but use a quality charger with Automatic overcharge protection. If the battery is new and Ok then you shouldn't be getting that warning unless you were running some accessories with the engine off for a while. You should still be able to start it with that warning although it is harder on your Alternator to do all of the charging of the battery and a normal load, and it is an expensive Alternator so why put the extra stress on it.

There are some details that I am assuming, battery condition and such. It could be a bad battery, a parasitic drain larger than normal ( Cayenne does have a lot of Parasitic drain, I keep mine on a battery tender if I'm not driving it for a few days), bad Alternator/voltage regulator, dirty connections (Ground and/or Positive lead), etc....

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do you mean I can charge it through the jumpstart terminals?

The challenge I have is that the place the car is parked has no AC power outlet. (Idon't have any garage in my flat in Hong Kong)

do you think I can use a fully charged portable jumpstarter to charge the battery through the jumpstart terminals at the engine compartment?

Any advice is much appreciated.

In the engine compartment there is a charging positive and negative terminal under the small plastic cover on the left rear of the compartment (LH Drive at least). Pop the cover and there is a Ground post and just to the rear of it there is a Red plastic flip cover you flip up to reveal the Positive terminal. If you have time I would slow charge it with a 2~4 amp charger at least over night if not upwards of two days. If your in a hurry faster charge it with 6~8amps but use a quality charger with Automatic overcharge protection. If the battery is new and Ok then you shouldn't be getting that warning unless you were running some accessories with the engine off for a while. You should still be able to start it with that warning although it is harder on your Alternator to do all of the charging of the battery and a normal load, and it is an expensive Alternator so why put the extra stress on it.

There are some details that I am assuming, battery condition and such. It could be a bad battery, a parasitic drain larger than normal ( Cayenne does have a lot of Parasitic drain, I keep mine on a battery tender if I'm not driving it for a few days), bad Alternator/voltage regulator, dirty connections (Ground and/or Positive lead), etc....

If the goal is just to start the engine, those portable boosters should work as long as you get a BIG one e.g., this one http://www.cloreautomotive.com/sku.php?id=262 Not sure you could get it in HK. Once the engine is running, the alternator should be able to charge the battery if it's not completely dead.

If you only connect the booster to the car (via the jump start terminal) w/o starting the engine, the booster will charge your battery only sligtly, and most likely not enough to make your battery start the car on it's own because to fully charge a battery, you need 13.5-14.5v, which the booster pac cannot supply.

Edited by Ahsai
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I just want to charge the battery without taking out the battery which is so cumbersome.

Before the engine starts, the voltage is only 11.4V (the battery is just 2-month old), after starting the engine, the voltage goes up to 14V(alternator is working) Theoretically, the alternator should be charging the battery, however, the voltage remains 11.4V, not going up nor going down.

That's why I want to charge the battery.

the practical symptom I have is that the aircond starts only 2-3min after the engine starts, consistently.

if the voltage is at 12V or above, the aircond starts immediately after the engine starts.

I have done a number of experiment to validate this.

now I have a portable jumpstart power pack. I am purchasing the Porsche battery maintainer from UK

I plan to charge the battery like this :

Jumpstart power pack (13.3V) --> 12V-220V-DC-AC-inverter --> Porsche battery maintainer---> Cayenne S(12V socket)

do you think this would work?

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How long did you let the car running? If after say an hr of driving your battery is still at 11.4v, I think you need a new battery.

Your setup might work but still it's only good if you have a healthy battery to begin with.

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You seem to want to spend a lot of money to provide a work around rather than solve the problem. I was under the impression that all 2003 V8s were supplied with dual batteries so you may want to confirm this before proceeding in another direction.

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This is the 3rd battery in the last 12 months. it am pretty sure it is a healthy one.

There is an auxiliary battery at the rear, both are few months old.

I was told the Aux battery only support the engine start, not running the accessories.

somehow, the alternator is not charging the battery much.

the car runs ~600km per week.

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Btw, this tester is great. You can leave it plugged in the cigarette lighter. At the end of your drive, just lock your car and you can see the volt reading through the window. Next morning, you can check again before unlocking your doors. If you see a low reading in the morning, you are pretty sure the battery is draining. In this way, you can see the actual readings without the extra load of the electronics when you open the door, before arming the car, etc. Of course it monitors the alternator output when the engine is running.

http://www.amazon.com/gp/product/B000EVWDU0/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1

Edited by Ahsai
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Btw, this tester is great. You can leave it plugged in the cigarette lighter. At the end of your drive, just lock your car and you can see the volt reading through the window. Next morning, you can check again before unlocking your doors. If you see a low reading in the morning, you are pretty sure the battery is draining. In this way, you can see the actual readings without the extra load of the electronics when you open the door, before arming the car, etc. Of course it monitors the alternator output when the engine is running.

http://www.amazon.com/gp/product/B000EVWDU0/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1

I use that same tester (a handy tool for your toolbox).

If the original poster is having abnormal current draw with the car OFF and unlocked - then he should start the process of finding the draw.

Although it can be a bit time consuming removing a single fuse at a time until the current draw drops is the easiest way for the DIY'er to find the problem circuit and then the problem.

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Thanks for the advice!

I will observe whether there is a voltage drop overnight.

but finding out the drain by pulling one fuse at a time is a extremely time consuming job.

there are over 100 fuses in the 3 fuse boxes !

Note you could only see the real voltage of the battery with the doors closed and armed. The reason is once you open the door, lots of electronics and light bulbs will come online which will lower the voltage quite a bit hence my suggestion of the tester reading through the windows before you unarm the car. Also, after you turn off the car, the computers are still running for a while (tens of minutes or more) until you arm the car, at which point only the alarm will be drawing very little current (tens of mA at most).

Edited by Ahsai
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I would start by asking if you have installed any new aftermarket toys? IE: radio, nav system, alarm? If so I would start with that fuse group. Hope this helps.

I have not installed anything new nor any new toy.

It seems to me the battery keeps depleting.

Over the last few days, what I did was that I charged the battery by connecting to the jumpstart terminals with a jumpstart power pack.

it did charge the battery! The voltage (in armed state) went from 11.6V to 12.2V.

However, the "Start Engine" still appears before the engine is started. so I guess the battery is still not fully charged.

The next experiment I will do is :

jumpstart power pack--> 12V-DC-220V0AC inverter-->Porsche battery maintainer-->Cayenne S 2003

I am awaiting the Porsche battery maintainer shipment from UK.

I will share the result few days later.....

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