Battery Drain - 996.2 turbo

[justk2020]

Hi,

I've been caught with a flat battery twice in the last few weeks.

Main question:

Would it be usual for a charged 80/95ah battery to drain (enough to fail to start) in under 1hr ...if sat parked, engine off, with lights, fans, radio (new head unit), 60w (3a) cigarette lighter phone charging....all on?

This was basically the situation...different battery each time.

Various background info:

I dont drive it often (sunday)....but it had been on a trickle and driven for 30 mina or so before parking up on tbese occasions.

The head unit is new and installed by me...and a prime candidate if what i am experiencing is unusual.

The phone charger is 60w and about as high powered as they go..and next candidate

I left if on ctek 10 for a couple of days....all the lights lit (battery holding charge...). Voltmeter 12.57 a day after i took it off trickle.

Amps measured in series with neg lead and neg post...0.007 amps in Amp setting. I am not convinced i am measuring it right as when switch to 200mA it just reads 0.

That's all i got. Any thoughts?

 

[deMort]

I'm not quite sure i understand this question .. you have the ignition on .. the headlights on and several other electrical items switched on and the car wont spin over after an hour like this ???

Yup .. i doubt it would if that's what you are doing ... also why would you want to do this ?

A voltmeter reading of 12.57 off charge and left for 24 hrs would indicate there is no parasitic discharge ..

An amp discharge test should give a reading of 0.030 - 0.070 .. that's 30 - 70 milliamps with 1 amp being 1K milliamps .

1 amp on a volt meter set at 20 amps ( the norm on most meters ) will be 1.000

I / we need a little more info on this please .. you need to be in a position to have ignition on and electrical loads on for a long period of time ? is that the question ?

If so .. a seperate power supply is going to be required .


Obviously no offence but i am a little confused .. mind you as i get older that becomes more common lol .

 

[justk2020]

This could be quite embarrasing...for me.

I don't "need" to sit there like that...I just happen to have parked up a couple of times (school run, rest stop) and not bothered switching anything off. Then havent been able to turn her over.

Having recently changed the head unit and had a few gremlins I just jumped to the conclusion that i have introduced a problem...rather than thinking maybe i just emptied the battery sat there "lit up"

So...if its no surpise at all that thr battery drained in 30/60 mins..then thats the answer lol..

Thanks Demort!!

 

[deMort]

Ok .. now i understand .. try turning off the headlights and the radio on will be just fine for a fair while .Headlights are a huge drain on a battery .

The more modern cars have monitoring systems that will shut down electric loads to save the battery .. yours won't have i'm afraid so you are in control .

I have one of these small battery packs that can jump start my bike .. you get the same for cars .. not a massive expense but it will certainly save you if the battery does get flat .

I would strongly advise you to get one .. along with anyone else as they are a damn good bit of kit to have for emergencies .

EDIT .. btw .. a question is a question .. there is no embarrassment as its a question that needs answering

 

[justk2020]

Thanks so much...that will definitely be it.

I just got used to my more modern cars and things like the lights staying on etc in the 996 keep catching me out etc. Muscle memory needed.

P.s. i got a jump starter like you mentioned, the first time and it bailed me out the second time. Brilliant bit of kit.

Regards karl

Charity donation on its way

 

[gizlaroc]

Yeah they are great.

But remember, leave it in the cabin, not the frunk.


I use one of these....

https://www.amazon.co.uk/gp/product/B015TKUPIC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It will stay charged for months. Will start any Porsche 3 or 4 times from a single charge.


I first bought one when I had a parasitic drain on my TDV8 Range Rover, it started that no problem at all too.




Good idea to jump on the jump points and not direct to battery.
I think I fried my instrument cluster through jumping direct to the battery on my 996.
And doing hours and hours of searching found quite a few people with the same issue as I had who had done the same.

The cluster would not sleep properly, clock would often be flashing when I came back to my locked car. Could not reset it until you had driven around for ages, after a few miles it would stop flashing and seem fine again.
Only a replacement cluster sorted it.

 

[deMort]

Charity donation on its way

Normally i don't answer after a question has been answered but just for reference and mainly for people that might read this ..

The charity i have listed is for Mark .. aka 911Time , a big contributor to this site .. it has helped him over the years and as i consider him a friend i have put it in my sig in case anyone wants to make a donation . Its voluntary trust me !

Friend is a difficult concept as i've never met him and probably won't but we chat regularly via email .. we keep each other up to date on what's going on in our worlds .. hence friends in that sense .

Either way .. Thank you .

 

[deMort]

Good idea to jump on the jump points and not direct to battery.
I think I fried my instrument cluster through jumping direct to the battery on my 996.
And doing hours and hours of searching found quite a few people with the same issue as I had who had done the same.

Jump starting any car is a bit iffy .. with a 996 you have the ignition key on to stop alarm activation .. but either way when connecting a battery jump start it can send a surge through the cars systems .. its this that damages electrical components .

Once a car has jump started then leave it a min or so before disconnecting the device as the same applies ... in this case it's a jump in alternator output to cover the lost load ..

Blown pcm fuse is a common one after a jump start ... to a degree obviously as i see far more faults than you guys do lol .

My thoughts anyways .

 

[Alex]

For reference, I was having a few battery problems a few months ago. After resolving any shorts I had that were draining the battery, I gave the battery a full overnight charge. I then had it tested with a proper tester that printed out a report. The battery was deemed 'acceptable' even though it wasn't up at 100%. I then did a trial with all the lights, fogs, heater fan, electric seats, heated mirrors and head unit all on without the engine running. Lasted about 17 minutes before everything stopped working. Fully overnight charged the battery again and tested and same 'acceptable' result. Battery was around 14 months old.

 

[Griffter]

It's not a hard and fast rule and some conditioners will claim to recover them, but in my experience if you drain a car battery it's never the same again. They can show the right voltage and start the car on a daily basis but they don't hold charge over the long term.