Help please - battery (and mouse) problems

Ok, so I didn't get to drive my 996 Turbo as much as I wanted or should have last year . I parked it up over the winter in my garage, because I don't have any winter tyres for it - which are compulsory here in Luxembourg. I remembered to charge it a couple of times, and roll it on the tyres a bit, but forgot for a while and now the battery is dead. Fortunately, I left the bonnet open (with the lamp disconnected, before any of you point it out). I tried to charge it, but the charger reads 14.6V for a few seconds and then goes down to ~3.0V and refuses to charge it. Is the battery dead, or do I need a special charger? I tried a few times to turn the charger on and off and eventually got the battery to nearly 4.0V, at which point the alarm started to sound and drained the battery dead again. I have no clue when the battery was last replaced. Is there a way I can tell how old it is? Do I just need a new battery? If so, which one (brand / type / part#) should I get?

They often carry the date of manufacture. Bosch S5 or equivalent would be my suggestion for a replacement.

You have probably killed the battery, 6 years is not bad though, I would just pick up a new one and remember to keep it on trickle charge next time you lay up for winter

Am afraid it sounds dead to me. As a general rule, if the voltage on a car battery is less than 12v its probably knackered (some people say below 12.1v). Lead-acid batteries aren't engineered to handle being left discharged.

Thanks all. I had a feeling I would have to buy a new one. I also heard that Bosch are the way to go - S4 010 or S5 010? Being that it's dead and I can't take it to a garage to change, how much risk is there to doing myself? I've read a load of caution messages, so how risky is it?

Very easy to change, you need a 10mm socket for the terminals and 13mm for the battery clamp. Make sure you reconnect the terminals the right way round and the little vent tube on the side Watch you tube video's, seeing it done makes all the difference..

As with any battery disconnect .. you undo the negative terminal first , so on a RHD car the o/s lead , then the positive , remove the battery clamp , 13 mm bolt. 996 and you need to have the key in the ignition and in the ignition on position .. alarm wil sound when fitting or removeing if not . Pull out the vent tube if fitted . I then put a towel in the boot , i climb in and i lift the battery up and onto the panel .. i then lift it out ot the car . Be aware .. our backs are not designed to lean over and try and lift these out so the above is the best way . 10mm spanner for the lead nuts . As mentioned above .. your battery is probably dead hence it wont charge . After replacement , reset the windows .. close and hold the window switch in the up position for 5 seconds , input radio code if needed . Also .. turn on the ignition but dont start the car for 30 seconds and dont touch the throttle pedal .. it resets . EDIT .. I will also add and just to be safe .. wear glasses or safety goggles .. not really needed but i prefer to say the safe way of doing things .

Thanks all, I'll give it a go.

So I did it Thanks to all of your suggestions. I went for a long drive and it felt nice to have a drive in it again, apart from... ...the only annoying thing... in the process of changing the battery, I noticed some mouse droppings in the boot, then in the engine bay, then in the car :x It must have decided to make it's home there over the winter, whilst the car was parked up in the garage. Any ideas as to how to get rid of a resident mouse? Apart from the obvious mouse trap...

Shut a cat in the car.

With regards to voltage see the sticker on a brand new S5 Bosch battery with regards to voltage and its guarantee:- "Keep above 12.1V if 50% discharged" and the "Warranty Void 10.6V and 100% discharged" Pip

Run engine to temp and it will kill anything on the engine .. Inside the car .. thats a big problem .. i would sugest get an Indy to look at it .. i know from experience its hard to get these little buggers out. They run up inside a channel and can be in the back or the front of the car .. although from my experience its the back and behind the rear quarter panel at the rear . Basically its a strip down .. they can cause a lot of damage in the areas they decide to nest .. they dont eat wire as such but they will try and remove wires if its in the way . Mouse trap .. forget it .. they dont work .. we have tryed cheese . chocolate and various meats just in case .. it dont work .. mice will hide , you have to get the traps in the " run " they use .. and thats behind the carpets ... remove the rear panels is my suggestion .

Not sure of the battery brand, there were no stickers whatsoever on the old battery. It now has a nice high-power battery I'm due to go to an indy next month hopefully, so will ask them to strip it down to find the mouse - I heard it whilst driving yesterday evening, so it's in the car rather than the engine bay. Let's hope it doesn't destroy to much in the meantime.

So I caught one of them in a humaine trap - I released the cute little thing about a kilometre from my house, so hopefully he won't find his way back anytime soon... Most people recommeded peanut butter to catch them, but I had to improvise with almond butter instead. Let's see how many more there are. As yet there are no more droppings inside the car since I hoovered it out

Well .. possibly problem sorted but you are far more humain than us mechaics .. thats for sure ! Best if i dont mention the nest with 7 babys in it that my collegue found once .. the insurence assor wrote the car off .. £15k of damage .. as for the mice .. hmm ... Ive had to once work on a car that was urine soaked to the point i couldnt breath in the car .. i put a respirator on .. my knees got damp on the carpet .. it wasnt water ! Anyways .. the food item .. very usefull for me but can you say where abouts you laid the trap please .. i know well the runs the mice take in these cars and getting the trap in the right place is key to this .. I might even let them go in future :hand: