Battery drain.
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Racer
Joined: Sep 2009
Posts: 258
Likes: 1
From: Ireland
Battery drain.
Is it normal for a 911 to drain its battery so quickly? I think its quite common on 997's?
I went out to my 997 this morning after not having used it for about a month and the battery was dead - again.
I bought a new battery last year thinking it might be a faulty battery but it drained it in the same manner so now I alternate the two batteries - and always leave the bonnet (hood) lid open so that I can get to the battery if it goes flat.
Could it be that the interior light is on under the bonnet as a result of leaving it open?
I always lock the car when its garaged so it goes into sleep mode if not used often but that does not seem to help much.
I went out to my 997 this morning after not having used it for about a month and the battery was dead - again.
I bought a new battery last year thinking it might be a faulty battery but it drained it in the same manner so now I alternate the two batteries - and always leave the bonnet (hood) lid open so that I can get to the battery if it goes flat.
Could it be that the interior light is on under the bonnet as a result of leaving it open?
I always lock the car when its garaged so it goes into sleep mode if not used often but that does not seem to help much.
Banned
Joined: Feb 2012
Posts: 1,251
Likes: 22
I use a Battery Tender to keep my battery charged because my 993's got schizophrenic and did weird things when the batteries were weak. I do not close my trunk lid all the way but close it to the point where the latch catches. The trunk light goes out after a few minutes and I can still activate the alarm; it is easy enough to see if your P lights are off by going into the garage when its dark.
Rennlist Member
Joined: Jan 2006
Posts: 1,107
Likes: 36
From: New Hampshire
Alfa, as I travel so much, my '06 Carrera S sits for up to 6 weeks at a time in the garage plugged into a Porsche battery tender. Happy to report that after 30K miles it's still on the original battery and never once has it had an issue starting.
Hope this helps.
Hope this helps.
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Drifting
Joined: Nov 2011
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From: Ontario
Is it normal for a 911 to drain its battery so quickly? I think its quite common on 997's?
I went out to my 997 this morning after not having used it for about a month and the battery was dead - again.
I bought a new battery last year thinking it might be a faulty battery but it drained it in the same manner so now I alternate the two batteries - and always leave the bonnet (hood) lid open so that I can get to the battery if it goes flat.
Could it be that the interior light is on under the bonnet as a result of leaving it open?
I always lock the car when its garaged so it goes into sleep mode if not used often but that does not seem to help much.
I went out to my 997 this morning after not having used it for about a month and the battery was dead - again.
I bought a new battery last year thinking it might be a faulty battery but it drained it in the same manner so now I alternate the two batteries - and always leave the bonnet (hood) lid open so that I can get to the battery if it goes flat.
Could it be that the interior light is on under the bonnet as a result of leaving it open?
I always lock the car when its garaged so it goes into sleep mode if not used often but that does not seem to help much.
If you'd like to pass over the keys, I know of a few friends that'll be more than happy to keep her warm !
Rennlist Member
Joined: Jun 2014
Posts: 445
Likes: 23
From: Toronto, Canada
Fell victim to this today....haven't driven the car much at all (stupid rain), and today wouldn't start.
I do have a battery tender hooked up direct to the battery now, need to buy the cig lighter adapter.
Odd that the battery (new Porsche battery installed by the Dealer as part of the CPO), is dead already. I will keep the tender plugged in when the car is going to sit for more than a few days.....
I need to drive the car more.......
I do have a battery tender hooked up direct to the battery now, need to buy the cig lighter adapter.
Odd that the battery (new Porsche battery installed by the Dealer as part of the CPO), is dead already. I will keep the tender plugged in when the car is going to sit for more than a few days.....
I need to drive the car more.......
8th Gear
Joined: Mar 2014
Posts: 8
Likes: 0
From: Wilmington, DE
I recently was told by service mgr at Porsche dealership that if the car isn't driven at least once/week, you're at risk for draining the battery (especially with an older battery). As others have said on this thread, get a battery tender.
Advanced
Joined: Jul 2012
Posts: 73
Likes: 0
From: SW Houston, TX
It's normal. If I don't drive it for roughly 30-40min every week it cranks really slow and may throw a 'PSM in diagnostic mode" message if the battery is really weak. Drive it more often or buy a trickle charger.
Race Director
Joined: Sep 2006
Posts: 19,031
Likes: 266
From: Bentonville, AR
If the battery is new or nearly new it might have enough margin to give you some more life but it could let you down again, almost certainly will let you down again at some point the future.
Thus I would bite the bullet and replace the battery then take whatever steps are necessary to keep the battery fully charged. If one can't drive the car every week or so and run the engine half an hour to top off the battery to replace what it lost over time and then at engine start some kind of battery maintainer is called for.
BTW, if one leaves the front trunk open this can have the interior light on which can drain the battery very quickly. At the dealer in the service bay while almost every car has its front trunk open the tech disconnects/unplugs the interior light so this doesn't discharge the battery.
There is a front trunk lid emergency cable release and what one can do is have the tech find this and reroute it so you can use this to open the trunk in the event the battery dies.
Or you can connect 12V power to the special post in the fuse box and then connect the 12V power source ground to the door latch. This supplies enough power for the front trunk latch to work. It will not recharge the battery or supply enough power to start the engine. Do not turn on the key if you use this technique to effect an emergency opening of the trunk.