Porsche 911UK Forum

Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.

Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.

996 battery problems

wagonface

Well-known member
Joined
4 Apr 2006
Messages
1,427
Along with tyres and tyre pressures, the most common thread topic on the 996 forum is probably flat batteries. I hope this thread helps to collate all the wisdom that is spread throughout the forum. If I have mised anything, pls PM me and I will add it, or just add it yourself. Also, if I have got anything wrong, let me know so I can remove it and people dont short circuit themselves...

1) Battery problems are very common. A combination of less than supercar-standard electronics, a large engine, and lots of modern electronic gizmos to run means the strain on the standard Porsche battery is large. If your battery dies, its not because you are a bad person.

2) Batteries are a consumable. A car driven for 30mins 4-5 times per week might have a battery last 3yrs or maybe more. A car driven less often or for shorter duration will put more strain on the battery as it doesnt get charged enough during a drive, and discharges when sitting idle.

3) A battery that goes completely flat 2-3 times is probably too knackered to carry on living in a 996, even if you charge it up fully. If you do need to charge a completely dead battery, disconnecting it from the car while charging will give it the best chance of rejuvinating to full strength.

4) Do not skimp on battery quality, it will hurt you in the end. A good quality battery (Bosch Silver, Varta, OPC) will always outlast a £30 one from the market, even if they have the same 'rating' (eg 80Ah).

5) Trickle charging is a great way to keep batteries alive if you dont drive that often. The CTEK 3600 is a good option, there are other brands as well (search for CTEK on the forum and other suggestions will come up). If you find the lead on the CTEK isnt long enough to reach your battery, go to Maplin and buy some more wire and connectors for £5, and get the soldering iron out.

6) In a factory spec.996 I believe the cigarette lighter is not always live (it is dead once ignition turned off, so wont deliver current to the battery). So before plugging the trickle charger into it, get a Porsche techy to make it live (1hr labour max) or connect the trickle charger direct to the terminals using the plugs supplied with a CTEK. To check if its live, plug in your SatNav or road angel, get out of the car and lock up. If it stays on...

7) If you park in the street, so cant trickle charge from the mains, there are solar panels that are supposed to trickle charge. Won't be as powerful as a mains trickle charger, but if its your only option...

8 ) The standard drain on a car when 'sleeping' should be in the region of 20-80mA (ignition turned off, locked up and left for 90mins). Faulty Trackers (shorting or their internal battery flat) or other non standard electronics left on will obviously increase this. You cant test this, its need to be a garage with decent electronics diagnostics. If you're interested in how its done, PM me.

9) The car 'goes to sleep' after 4 days of no action. Various systems shut down, including the remote alarm facility. Top tip for unlocking easily: Unlock using the key in the door. Immediately lock it using keyfob remote, then unlock it using keyfob remote. Much easier than unlocking using key and quickly having to jump in car and put key in ignition and turn.

10) If you need to jump start, you need to connect the jump leads to the actual engine (-ve) and a terminal located in the engine bay (+ve). This is shown clearly in your manual. Dont connect jump leads to your battery in the front boot.

11) If completely dead, you wont be able to access your front boot as the alarm keeps the manual bonnet-pull locked. Apparently there is a terminal on the fuse board (think its a 30A fuse) to connect a remote battery to which will let you open the front cover (earthing it elsewhere I guess, having never done it myself)
 
Quality, one for the 996 FAQ Section if that's OK :D
 
Can we add a little pointer down the bottom, that if you own Jeff's GT3, you need to turn the key to the right not left when trying to unlock it or my alarm goes off :) hehehe

Mine is purely special.....

In fact, there are lots of extra wires hanging around under my dash that don't look factory so I wonder if someone has fiddled.....
 
Jeff said:
Can we add a little pointer down the bottom, that if you own Jeff's GT3, you need to turn the key to the right not left when trying to unlock it or my alarm goes off :) hehehe

Mine is purely special.....

Stand on your head Jeff and follow the instructions... it's clearly a car designed for those from 'down under' :lol:
 
I had my C2 go into "sleep mode" for the first time yesterday, so I had to open with the key. I think I turned it left, but was immediatly deafened by the alarm.

It surely doesn't always do that? I see that someone obove said he has to turn it to the right to make it unlock, so I'll try that. Is it normal that if you turn it the wrong way the alarm goes off? I don't really want to annoy my neighbours again :)
 
If you turn it to the left, anti-clockwise (at least on mine) it doesn't open the door but "wakes the car up". You can then turn the key normally to open the door or remove the key and use the remote.

There is something about it in the manual but i'm a man and therefore have no need of one of those, preferring trial and (noisy) error instead.... :D

Editted to say "don't get it wrong in a garage as the alarm makes your head and ears hurt. Lots"
 
I work offshore and my car is garaged while I am away usualy for a month, unfortunately in a garage with no power. :?
I am worried that in the colder weather it will drain the battery while I'm gone. :(
Also will the alarm go off when the battery reduces to a certain state of discharge :?:
 
tojoatsea said:
I work offshore and my car is garaged while I am away usualy for a month, unfortunately in a garage with no power. :?
I am worried that in the colder weather it will drain the battery while I'm gone. :(
Also will the alarm go off when the battery reduces to a certain state of discharge :?:

Highly likely I'm afraid. Maybe buy a Bosch Silver and fully charge it before going away? At least in a garage it wont annoy the neighbours (but it will kill your battery)
 
What are the chances of running a solar charger into the car. You could sit the panel on the roof of the garage and run the wires in and into the car. Good panels will charge in overcast - they don't need sun, just light. Most are weatherproof etc. Food for thought?

Cheers,
Jeff
 
thanks for the info lads :thumb: , looks like the solar pannel option,but I may be already in need of a battery when i return as I am only two weeks into a four weeker now :?
 
wagonface said:
10) If you need to jump start, you need to connect the jump leads to the actual engine (-ve) and a terminal located in the engine bay (+ve). This is shown clearly in your manual. Dont connect jump leads to your battery in the front boot.

Thanks for all the info, very helpful. Ref the above, what happens if you do jump start by connnecting battery to battery? Say just supposing "a friend of mine" did that this morning because I am (oops I mean he is) too dumb to read the manual? It started, but might I have damaged something and not found out yet?

Thanks

[04 996 Targa Tiptronic]
 
HarryH said:
wagonface said:
10) If you need to jump start, you need to connect the jump leads to the actual engine (-ve) and a terminal located in the engine bay (+ve). This is shown clearly in your manual. Dont connect jump leads to your battery in the front boot.

Thanks for all the info, very helpful. Ref the above, what happens if you do jump start by connnecting battery to battery? Say just supposing "a friend of mine" did that this morning because I am (oops I mean he is) too dumb to read the manual? It started, but might I have damaged something and not found out yet?

Thanks

[04 996 Targa Tiptronic]

It's fine. To be honest, I see it as a convenience to have front and back jumping ability. We've safely jumped another Porsche from the battery. It won't hurt it.
The idea is to put the power as close to the alternator as possible to reduce the loss caused by cabling I believe. If it works, no problems...
 

New Threads

Forum statistics

Threads
124,354
Messages
1,439,445
Members
48,708
Latest member
JLav211
Back
Top