Problem unlocking with the key fobs?

[Jakub]

Hi, I left my car stationary on the street for last two days.
Today (after a cold night) the car was dead – no reaction to the key fob.
The led on the fob was blinking red. “Battery in the key fob is gone” I said to myself and went back to get 2nd key. The other key would not work. Sounds like death battery in the car? Well, I just gave up, went home and got Audi keys.
On my way to Audi I did press the Porsche fob again and it worked.
Car started without any problem... Last time it was used on Friday, just 2 days ago.

What could be the reason?
Thank you,
Regards,
Jakub

[TheDeadPrussian]

My car does not react to the fob to unlock if left for a period of time (usually greater than 2 days however).
Just unlock the door with the key and then press the fob to disable the alarm. The alarm does not go off the moment you open the car, but will do if you don't then press the fob within about 20 seconds.
I presume it is some kind of ‘sleep mode’ to reduce the car battery drain from the fob sensor.

[Jakub]

TheDeadPrussian said:

I presume it is some kind of ‘sleep mode’ to reduce the car battery drain from the fob sensor.

Yes I know about the sleep mode but:
- sleep mode should start after 7 days of inactivity
- I was able to open the car remotely after a while

[993AL]

TheDeadPrussian said:

My car does not react to the fob to unlock if left for a period of time (usually greater than 2 days however).
Just unlock the door with the key and then press the fob to disable the alarm. The alarm does not go off the moment you open the car, but will do if you don't then press the fob within about 20 seconds.
I presume it is some kind of ‘sleep mode’ to reduce the car battery drain from the fob sensor.

Alternatively, you just lift the door handle once and the system awakes, your fob should then work, it does on the 997 GT2.

[Jakub]

Actually I remember lifting the door handle in the process.
That may explain it. Thanks.

[gsewell]

In which case, it may be that your main battery is getting marginal in this cold snap and the elctricery is just trying to protect itself by going into sleep mode early having detected a drop in voltage.

[Jakub]

gsewell said:

In which case, it may be that your main battery is getting marginal in this cold snap and the elctricery is just trying to protect itself by going into sleep mode early having detected a drop in voltage.

Good thinking! Thanks.

I am forced to park on the street, which makes use of battery maintainer impossible.
I know that I will go away for couple of days soon and the battery may die.

What would you do? :
- Buy another battery and keep it ready (Porsche one or same spec Bosch etc?)
- Buy a battery charger and recharge the battery after coming back
- Buy a battery powered car jump-starter (is there any good for a Cayman?)

[thegoose]

I'd suggest a solar-powered trickle charger - will keep whatever battery you have fitted in better condition all year round. Maplin do this one.

[FlybyWyre]

I tried the Maplin solar charger and found it had the opposite effect.

I have a Halfords power pack 200 because I need to leave cars for an unknown length of time. Part of life working offshore.

Really recommended and much more convenient than waiting for the AA to come at 0200hrs. It also has an invertor to supply 240V if needed for the laptop etc.

[Jakub]

As I am do drive short distances and this is not my only car, going for a battery charger is probably the best solution.
BUT I need this Halfords power pack 200 to get to the battery anyway.
The solar charger would be the best solution but I do not believe that this may actually work good enought?

[thegoose]

Jakub said:

The solar charger would be the best solution but I do not believe that this may actually work good enought?

It worked OK on a friend's 996 3.4, and for £20 has got to be worth a shot. Maplin actually did those chargers half price for aaaggeesss but sadly no longer. If you're local I'll sell you one for a tenner (I keep cars inside now and have lots of Aldi mains trickle chargers instead).

[Jakub]

Thanks
But I have ordered this from eBay just hour ago:

Ring RSP240
http://www.ringautomotive.co.uk/product_detail.asp...

It was just 29.99 so if works – good, if not – not a big deal, will use a Halfords battery charger.