Funny thing happened to me this morning (verbose)

[Highlander]

Went out to my '01 Boxster this morning and when I pulled the door handle, the window did not go down - ohoh. Went to put my spare key in the ignition (couldn't find my primary key) and lo and behold, there was my primary key already in the ignition. The battery is as flat as gopher on a freeway! :cursing:

No problem I think, I'll just hook up my battery charger to the auxiliary terminal in the fusebox that the nice Porsche engineers put there for this very problem. Hooked everything up and got a spark when I attached the -ve clip, so we have power. Set the charger to its 50amp "start" setting to make sure we have plenty of juice. This illuminated the airbag light on the dash, but only the airbag light, nothing else. The led on my CDR23 radio was also blinking funny. Blink, blink, blink, pause, blink, blink, blink, pause... hmmm, what's up with that. Anyhoo, crossing my fingers, I pulled the front trunk release button and.......nothing, nada, not a sound - dammit! :censored:

OK, I'll just leave the charger attached for 5 minutes or so and go get a cup of tea. Came back 10 minutes later and looking through the rear window I could see the airbag light was still on. Funny, I removed the key and closed the door, why is the airbag light still on? Ah well, opened the door - no domelight, no clock, no odometer. Not good! Tried the front trunk release again....still nothing :angry:

Time to initiate plan B - call my local Porsche tech. Didn't take long for the dealership to get "H" on the phone (yup, that's what he likes to be called, "H") Explained what I was doing and he asked "Do you have another battery you could hook up to the auxiliary terminal?" Well yes, but shouldn't 50amps from the charger be enough? "Well no", he said "We have always had success using another battery". "OK", I tell him, "I have an emergency start box in my wifes car, I'll give it a try."

So I turn off the charger and hook up the start box. Everything looks the same, the airbag light is the only sign of life on the dash and the radio is seemingly mocking me with its blink, blink, blink, pause, blink, blink, blink, pause... Pull on the trunk release and "click!", it's open :thumbup: Opened the trunk, accessed the battery, hooked up the start box to the battery and after a few cranks, she started right up :clapping:

So, this got me thinking. Why did the battery hookup work, but the battery charger did not?

Any suggestions?

Graeme

[Tool Pants]

As a former history major, all I remember about electricity is Ben Franklin and a kite and a key.

I have a charger with a switch. 2 or 10 amps for charging, and then 55 amps to start a car. I would not try to attach a 50 amp charger to that red jumper thing in the fuse box. I cannot believe you did not fry something. It is for opening the trunk, not charging the battery.

We had a local 2001 owner with a monster stereo and his battery died and could open the front trunk. He did not have a spare battery, so he used a 9 or 12 volt adapter you plug into the wall.

Hope someone has a better response than me.

[Fletcher]

Same thing happened to me the second week I had the car! Many chargers will not charge a completely dead battery (needs at least 3-4volts to accept a charge. Just remember if it happens again use jumper cables and you will be right as rain. Oh and the official battery drain to zero is about 30 hrs when key is left in dash but not in the on position. The good news is now I have 2-chargers and a set of jumper cables......!

[Highlander]

As a former history major, all I remember about electricity is Ben Franklin and a kite and a key.

I have a charger with a switch.  2 or 10 amps for charging, and then 55 amps to start a car.  I would not try to attach a 50 amp charger to that red jumper thing in the fuse box.  I cannot believe you did not fry something.  It is for opening the trunk, not charging the battery.

I'm a EE major and I have a theory why the battery charger didn't work. I need to get my charger into the lab here at work to see if I'm right.

The 2/10/50 amp thing is a current limit - no real danger of doing any harm no matter what the switch is set to. I did notice that it made no difference what setting I had the charger on, the meter on the front read less than 1 amp. When I attached the charger to the battery directly, the current went up to about 10 amps! That implies to me that the little post is isolated from the rest of the electrical system somehow.

I'll report back once I get a chance to look at the charger in the lab and see if I can come up with a good way of being able to use it to pop the trunk. Jumper cables are a PITA and being able to use the charger is just more convenient.

Graeme

[Tool Pants]

Good. We can get the straight scoop from an EE.

A charger puts out 12 plus volts so you would think it would work. Is your charger the automatic type that shuts off when the charger senses the battery is charged. That is what I have, but I do not think it is automatic in the start mode. Also my charger will not charge in the automatic mode if the battery is completely dead, there is a switch to put it in a manual mode so the battery will start charging.

Don't know if this helps.

When the electric releases first came out I asked a mechanic if you could use the little red post when a battery cable had been disconnected. He said yes, that the post had its own circuit and you did not need a connected battery to complete the circuit.

Then a few weeks ago a 996 owner with electric releases removed the battery to replace it, and left the front trunk open. Someone closed it on him. He tried to use his new battery on the post and it did not work. Ended up having to use the emergency release cable. So what the mechanic told me must not be true.

I have the 2001 wiring diagrams, first year of the electric releases, but the way Porsche puts them together is very hard for a history major to follow.

[mrmickeymouse]

If voltage is needed , it seems it would be prudent to check continuity from the "Red Post" to the switch, to see if it truly directly connected.

If not, maybe a voltage eater [who knows], may be why adding voltage does not "Pop" the switch.

The problem may be that the vehicle sense's low voltage and isolates parts of the vehicle to maintain some voltage, in the areas it considers important.

There may be a work around.

Just my two cents.