Porsche 718 Forum banner
21 - 40 of 41 Posts

·
Registered
2021 Boxster
Joined
·
2,402 Posts
Two months Without having the car connected to a charger? And the car started up ?
Aye. No lag or delay.... Usually The Bee is run once a week (at least) but a two month sabbatical interrupted life plans.
 
  • Like
Reactions: YD718

·
Registered
Joined
·
589 Posts
I have a new 2022 boxster gts two months ago delivered so battery is brand new. Im leaving for vacation on a Tuesday and can have my son start the car (not drive it cuz he’s not insured) on Friday thru Sunday morning and then again the next weekend on Friday thru Sunday and then im back on Tuesday. So the car will not be driven for 13 days straight but not started up for no more than 4 days straight.
Do i need to connect the car with a battery charger i have the porsche original one. I prefer not to because nobody will be home and am worried for malfunctioning and fire hazard.
If i come back and the car doesn’t start if I connect the battery charger will that fix it?
if you have a secured, private garage - don't set the alarm system (this draws additional power)

any add -on devices (dash cams, radar detectors) should be powered off or disconnected (parasitic power draws)

the volatile memory items draw a very small amount of current, especially once the CANBUS goes to "sleep" when it doesn't detect key fobs (Enter & Drive) doors / frunk / trunk lights from being open

Its a waste of time and energy to start and run a engine - you're not going to appreciably "recharge" a battery - it would take 3/4 tank of driving to charge a low battery that was too weak to crank and start an engine.
-cold starts are the highest wear event with an engine

-you want to operate all the systems for several miles after ALL the fluids (engine oil, transmission, diff) reach operating temperature - especially engine oil. Operating > 212* F gets the condensation out from cold start

-exhaust systems get a lot of condensation - another point to drive longer trips (after everything is at operating temperature) to drive condensation out of the exhaust system. There's a lot of condensation that forms in an exhaust system from cold start through warm up - if it doesn't dry out, it "rots" the system from the inside out.
More stainless steel is used in modern exhaust systems, but there's still baffles spot welded and the insulation / sound absorber materials get condensation in them as well
 

·
Registered
Joined
·
2,195 Posts
In other words not driving for two weeks and not maintaining the battery with a charger during that period shortens the battery life ? And using a charger during those two weeks is better for the battery’s life soan?
Not driving for two weeks and not using a battery charger will likely not damage a good AGM battery. Not driving for two months might, or might push it closer to its end if it is already old. I would not think using a charger over a two week span is required. But I think those here who go for three or four months that way may end up replacing their fairly expensive batteries sooner than the expected lifespan of an AGM battery would dictate. Just because it starts when you finally get back home doesn't mean it is just as fine and healthy as when you parked it.

The point I was trying to make is that our cars do use battery power while sitting still, and if you let it go long enough you run the risk that it will grow old faster/sooner. From what the display on my battery charger/maintainer tells me, two weeks might be a good threshold for doing something or not doing something. Or three weeks, or four weeks, whatever. I don't know that two weeks is a no-later-than cutoff, but what the heck, it's better to do something sooner than later.

When my sweetie and I go away for two weeks I give the keys and registration to a trusted neighbor with instructions to have some fun when the mood strikes. He has never complained 🏎 about being asked for a favor. He spends a lot of time doing this 🚴‍♀️ and is one of only three people besides myself and folks at the dealership who have ever driven my car. (The other two are my twin brother and a former boss, a good techie who at one time or another has owned a Boxster or an MR-2.)
 

·
Registered
Joined
·
589 Posts
I have conventional flooded cell batteries in my "fleet"

one battery was replaced in August 2008 (yes, just shy of 14 years) - trunk mounted batteries for the win. Its a standing record as my past was 7 1/2 years

my newer vehicle (built 10 / 2015) has its original battery (probably from 9/15) so its going on 7 years (also trunk mounted - as it shares a MB design)

the newer vehicle can sit for a week - 10 days at a time (not armed) and the battery is always on the ready

when its time for replacement I'll go with AGM - the prices are ~ $25 - 30 more and the lifespan is greater on AGM over flooded cell batteries
 

·
Registered
Joined
·
483 Posts
First let's do terminology:

  • Battery Chargers
  • Trickle Chargers
  • Battery Tenders/Maintainers

Chargers are only used to "charge" batteries. Tenders/Maintainers are used to maintain batteries and will never(*) overcharge.

(*) I have personal knowledge that a damaged tender/maintainer will kill a battery. So, don't use them for hammers.

What I write below is applicable to Tenders/Maintainers. Only. Unless I specifically write Charger.

When do you use the charger?
Never. See above.

So what’s the mode of operation regarding the charger to get more from the battery for more years?
If I am reasonably certain that I won't be driving the car for two or more weeks I hook up a tender.

We've nine cars and only one commuter so most of the cars are on tenders most of the time.

The wife's commuter 991S is equipped with front/rear cameras that run in parking mode all of the time when parked. That mode, with the installed optional radar-activation is pretty miserly with parasitic draw. I did the calculations when I put it in two years ago and it should be totally fine for 2 to 3 weeks. (Without the radar-activation the figure is about a week, sitting.)

On the weekends, I put it on a tender.

The truck (Macan) always sits outside and is generally operated once or twice a week. About once a quarter it gets "electron therapy" - I hook it up to a charger for a few hours and then swap for the tender for a day-ish.

The Macan's battery is 7 years old at this point. Given how it's treated I do not expect it to last too much longer. But, we'll see.

Are you saying that you are using an AGM charger on the factory wet cell battery?
@Barryng provided a veritable treatise on batteries. I use an AGM tender on our AGM batteries.

Note further than an "old-school" smart non-AGM tender will maintain an AGM battery. It just won't be as quick to reach maintenance mode. But, even so, I mostly use AGM tenders on the AGM-equipped cars.

Our cars cars have a lot of background uses for electricity when not running. I suppose that might depend on what services the car does or doesn't have. I know that I have occasionally gone for two weeks without driving, and when I put a battery charger on it the display said it has around 50% or even a bit less.
Our cars will go into a "sleep mode" - at least when left unlocked - such that they can sit for several months and still start.

I've accidentally left one of ours off a tender for a three-ish months and the only evidence was the "auto-start/stop off" warning. However, our cars are unlocked when in the garage. I have no data on how long they can sit locked and then still start.

There is a "transport mode" than can be set with PIWIS that, I suspect, minimizes parasitic draw at the expense of convenience (Entry and Drive, etc.)

Let me add that, with the exception of the Macan, none of our cars are equipped with Entry and Drive.

In other words not driving for two weeks and not maintaining the battery with a charger during that period shortens the battery life ? And using a charger during those two weeks is better for the battery’s life soan?
Again... not a charger.

If you only drive your car every two weeks and then only for a short period then, in my opinion, yes you will shorten the life of your battery if you don't keep it on a maintainer.


My Boxster usually stay in parking for the whole winter 3-4 months w/o battery maintainer and still can start the car after that.
Yup. But, do not expect that the battery will last for more than 6 to 8 years. If it's already 8 years old then expect it to die any day now.

If everyone goes back and re-reads @Barryng's post the between-the-lines implication is that starting and driving a depleted battery will cause damage to the battery. If your battery is at 50% and you drive around you will expend some of its calendar life. Even AGM batteries are subject to damage from mechanical shock (vibration, boucing from driving) when in a far-from-topped-off state.

The surest way to kill a battery dead is to discharge it fully, then charge it just enough to start the car and then drive away. 100% of the time you will kill the battery or at a minimum greatly shorten the battery's life. For the old pre-AGM batteries it was 100%. For the AGM batteries? I have no data.

If you forget to put a tender on your battery for a couple of months, then I consider it best practice to top it up with the tender before starting the car.
 

·
Registered
Joined
·
2,195 Posts
Our cars will go into a "sleep mode" - at least when left unlocked - such that they can sit for several months and still start.
You may be quite right on that. Running the alarm system with its internal motion sensor is certainly one power draw. But then, running the receiver to detect the wireless key fob also takes power. Running the telephone receiver to respond to Car Connect queries also must take some power. More importantly to me and presumably to you too, I would never leave the car unlocked, especially for an extended period, unless it was in a locked garage.
 

·
Registered
Joined
·
116 Posts
This topic is dense !

I use a ctek charger when I travel away for more than 2 weeks. In fact I have the same ctek model in my order 2013 BMW and battery works perfect.
 

·
Registered
Joined
·
615 Posts
This topic is dense !

I use a ctek charger when I travel away for more than 2 weeks. In fact I have the same ctek model in my order 2013 BMW and battery works perfect.
This. If I'm not driving it for more than two weeks, on goes the CTEK. The amount of over thinking some people do on this topic never ceases to amaze me. Worf did a great job at patiently explaining the nuisances in terminology but it likely won't get read by many.
 
  • Like
Reactions: mitsuba and worf

·
Registered
Joined
·
527 Posts
Running the alarm system with its internal motion sensor is certainly one power draw
Very true, which is why when I have the car in my locked garage, I double click the lock button to arm the alarm "without" activating the internal motion sensor. That is an option for those of you that didn't know it existed.
 

·
Registered
Joined
·
215 Posts
Discussion Starter · #30 · (Edited)
First let's do terminology:

  • Battery Chargers
  • Trickle Chargers
  • Battery Tenders/Maintainers

Chargers are only used to "charge" batteries. Tenders/Maintainers are used to maintain batteries and will never(*) overcharge.

(*) I have personal knowledge that a damaged tender/maintainer will kill a battery. So, don't use them for hammers.

What I write below is applicable to Tenders/Maintainers. Only. Unless I specifically write Charger.



Never. See above.



If I am reasonably certain that I won't be driving the car for two or more weeks I hook up a tender.

We've nine cars and only one commuter so most of the cars are on tenders most of the time.

The wife's commuter 991S is equipped with front/rear cameras that run in parking mode all of the time when parked. That mode, with the installed optional radar-activation is pretty miserly with parasitic draw. I did the calculations when I put it in two years ago and it should be totally fine for 2 to 3 weeks. (Without the radar-activation the figure is about a week, sitting.)

On the weekends, I put it on a tender.

The truck (Macan) always sits outside and is generally operated once or twice a week. About once a quarter it gets "electron therapy" - I hook it up to a charger for a few hours and then swap for the tender for a day-ish.

The Macan's battery is 7 years old at this point. Given how it's treated I do not expect it to last too much longer. But, we'll see.



@Barryng provided a veritable treatise on batteries. I use an AGM tender on our AGM batteries.

Note further than an "old-school" smart non-AGM tender will maintain an AGM battery. It just won't be as quick to reach maintenance mode. But, even so, I mostly use AGM tenders on the AGM-equipped cars.



Our cars will go into a "sleep mode" - at least when left unlocked - such that they can sit for several months and still start.

I've accidentally left one of ours off a tender for a three-ish months and the only evidence was the "auto-start/stop off" warning. However, our cars are unlocked when in the garage. I have no data on how long they can sit locked and then still start.

There is a "transport mode" than can be set with PIWIS that, I suspect, minimizes parasitic draw at the expense of convenience (Entry and Drive, etc.)

Let me add that, with the exception of the Macan, none of our cars are equipped with Entry and Drive.



Again... not a charger.

If you only drive your car every two weeks and then only for a short period then, in my opinion, yes you will shorten the life of your battery if you don't keep it on a maintainer.




Yup. But, do not expect that the battery will last for more than 6 to 8 years. If it's already 8 years old then expect it to die any day now.

If everyone goes back and re-reads @Barryng's post the between-the-lines implication is that starting and driving a depleted battery will cause damage to the battery. If your battery is at 50% and you drive around you will expend some of its calendar life. Even AGM batteries are subject to damage from mechanical shock (vibration, boucing from driving) when in a far-from-topped-off state.

The surest way to kill a battery dead is to discharge it fully, then charge it just enough to start the car and then drive away. 100% of the time you will kill the battery or at a minimum greatly shorten the battery's life. For the old pre-AGM batteries it was 100%. For the AGM batteries? I have no data.

If you forget to put a tender on your battery for a couple of months, then I consider it best practice to top it up with the tender before starting the car.
I have this I imagine it’s what you call a maintainer? From everything I’ve read on this thread I can’t find any negative issues with using a maintainer even if the car stands for two weeks only when im on vacation to be on the safe side ? Your opinion?
 

Attachments

·
Registered
Joined
·
483 Posts
I have this I imagine it’s what you call a maintainer?
Yup. That’s a tender/maintainer. It’s one of the CTEKs with the expensive Porsche logo.

From everything I’ve read on this thread I can’t find any negative issues with using a maintainer even if the car stands for two weeks only when im on vacation to be on the safe side ? Your opinion?
A tender/maintainer will not hurt anything. If you want to hook it up every time you stop the car you will not hurt anything.
 

·
Registered
Joined
·
589 Posts
@Barryng provided a veritable treatise on batteries. I use an AGM tender on our AGM batteries.

There is a "transport mode" than can be set with PIWIS that, I suspect, minimizes parasitic draw at the expense of convenience (Entry and Drive, etc.)

[/QUOTE]
That's a hidden "engineering menu" item on a number of cars - I know more recent Dodge models have a "transport mode" that can be activated through steering wheel button controls and turns off many ancillary systems - when the vehicle is restarted, it turns off the transport mode

I wonder if there's one for Porsche like that as well

Typically the keyless entry systems go to "sleep" after the fob is out of the proximity of the vehicle (often greater than 8') the fob sends a signal to the proximity antenna and that's how it knows to turn on the door handle sensors to allow that function.
 

·
Registered
Joined
·
104 Posts
You will be fine connected to your battery maintainer for the duration of your trip. Hook it up, make sure all the settings & lights are doing the right things and you're good to go. The car won't need to be started, but if you are concerned just have your son check to see that all is normal with the charger every few days.

FWIW, I use a CTEK brand on mine (same manufacturer as your unit) whenever the car is parked at home. It sometimes goes 2 weeks without a drive and zero issues with the battery or with the maintainer.
 

·
Registered
Joined
·
34 Posts
I have a 2019 boxster that is on the original battery that has no problems being left unused for three weeks without a battery tender. I have noticed a message on one occasion saying something like “battery saving mode” when starting it after 3 or 4 weeks not used. I usually close the soft toptop just as I start it and put it in the garage.
Starting the engine and raising the soft top must place s fair load on the battery. After realising this I bought a CTEK and now connect this if Its not going to be used for a couple of weeks or more.
 

·
Registered
Joined
·
126 Posts
Have gone over two months without starting. No problem. Car is garaged, A/C at 78, top down.
Have gone over two months without starting. No problem. Car is garaged, A/C at 78, top down.
Raven, are you saying your top has been down for 2 months? I ask because I'd be concerned in doing that with the top developing some pretty major creases that would take a long time to work out.
 

·
Registered
Joined
·
126 Posts
Unproven rumor has it that regular use of an AGM smart charger might extend the life of the OE battery. Maybe yes, maybe no, but I'm on year 6 of the OE battery and voltages are still good; Varta.
What are your battery voltages at year 6? Mine is year 5 and I'm starting to see some decline. Was 14.3 while driving and in recent weeks has slipped to 14.1. I typically drive the car mostly on weekends for short distances and when not driving it, I always use the CTEK battery tender. I took my car into the dealer 2 weeks ago for its annual oil change and 27 point check. I asked them to test the battery life and I was told they did that and it is near end of life. I was quoted something like $837 for a new AGM battery.
 

·
Registered
2021 Boxster
Joined
·
2,402 Posts
Raven, are you saying your top has been down for 2 months? I ask because I'd be concerned in doing that with the top developing some pretty major creases that would take a long time to work out.
I participated in a previous blog regarding tops and creases. On the few occasions I've put the top up no creases have appeared. I'll take some photos Saturday and post them.
Maybe the newer tops use a different material or the mechanical folding has changed? I have no experience with previous models. This top feels thick and plush compared to other rag-tops I've owned.
 
21 - 40 of 41 Posts
Top