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Discussion Starter · #1 ·
Hey All,
With the cold months need to keep my battery up while vehicle in garage.
Anyone use the Porsche Pro Premium Battery Maintainer? (Also see CTEK is the creator) And use the one with the Cigarette Lighter connection?

Do they work well - seem safe to use?
Ok to go with Manuf. CTEK brand to save money $$$? Say through Amazon.

Thanks,
RVACS
 

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Discussion Starter · #3 ·
I have a CTEK and use it through the cigarette plug on the passenger side of the center console with no issues at all.
Can you possibly get the model number off it so I can look it up online? Thankx
 

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If you do a search here, there was a service bulletin describing an issue where the system goes to 'sleep' to save power and cuts off the cigarette lighter jack (my impression is the car must be sitting a very long time to get to the point where it tries to gradually shut down electrical systems), in which case they recommend using the alligator clips or the ring terminals attached to the battery. If you buy the CTEK (not the Porsche branded unit) it will come with both the alligator clips and the ring terminals, and a connection to swap them off of the cord. It also accommodates a 12V extension cord from CTEK (although there's no reason you couldn't use a regular extension cord on the 120V end of the unit). You would need to buy the cigarette lighter plug separately with CTEK whereas the Porsche branded unit is hard wired for the cigarette plug only.

I noticed that the dealer demo cars and showroom models seem to have a plug wired into battery ring terminals under the frunk lid. That may be a practical thing because then the wire is less obtrusive to shoppers sitting in the cabin.

Full disclosure I have not tried the CTEK on my boxster yet because it doesn't exist (dealer just got the allocation and wrote up the order yesterday!). However the MXS 5.0 has additional mode settings that suggest it's an updated version. You can select motorcycle/atv, car, motorcycle recondition, car recondition, car AGM (which skips the recondition phase of the program), and car AGM recondition (for batteries that have been deeply discharged). My understanding is that the boxster has an absorbed-glass-mat (AGM) battery. I bought it early thinking I could use it on my '01 Mazda Miata, but that car disconnects the cigarette lighter when the ignition is turned off so i have an older battery minder plugged into ring terminals on the battery of the Miata (which also has an AGM battery).
 

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CTEK MXS 3.8. Directly on the battery on the positive and a bit further on the negative. The 718 has a special negative spot for it (don't know why).
It maintains the battery very well. Even when it's really cold.
 

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Discussion Starter · #8 ·
Ok thanks all - Think I will go with CTEK MXS 5.0 with cigarette cord attachment for now...may do the other attachment at a later time. By the way @Bob V - look at this info - think I just need to lock the doors and should be ok. For 2013-2018 Boxster, Cayman, & 911 Carrera models: Long term storage can put these cars in "Sleep Mode", which will disable the center console plug socket and shut off the battery maintainer. To bypass this, lock the door after setting up the battery maintainer. Or directly connect the battery maintainer to the recommended charging points using the optional alligator clips.
 

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CTEK via the 12v socket in at the passenger footwell. This seemed to change after 2017 where it was originally only possible via the center console.

I use my car for a daily driver but as short journeys I top up the battery once a month.
 

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Ok thanks all - Think I will go with CTEK MXS 5.0 with cigarette cord attachment for now...may do the other attachment at a later time. By the way @Bob V - look at this info - think I just need to lock the doors and should be ok. For 2013-2018 Boxster, Cayman, & 911 Carrera models: Long term storage can put these cars in "Sleep Mode", which will disable the center console plug socket and shut off the battery maintainer. To bypass this, lock the door after setting up the battery maintainer. Or directly connect the battery maintainer to the recommended charging points using the optional alligator clips.
You may want to do a search for "battery minder" or "winter is coming", to name a couple. There is lots of good info in other threads.
 

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I use the CTEK MXS 5.0 4.3 amp charger and maintainer plugged into the socket in the passenger footwell. It was purchased on amazon for about $80. Also purchased the eight foot extension cord for about $12 so I could run the wires in a tidy no tripping manner.
 
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I store my Boxster all winter using the Porsche brand battery tender (CTEK) plugged into the cigarette lighter in the passenger footwell and have had no problems over the past 3 winters. It does a great job.
 

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CTEK MXS 3.8. Directly on the battery on the positive and a bit further on the negative. The 718 has a special negative spot for it (don't know why).
It maintains the battery very well. Even when it's really cold.
To reduce the possibility of a spark igniting out-gassing that might be present from a car battery when jump-starting a car with another battery, it's best to connect to the positive terminal first, then connect to a ground point somewhere away from the battery. That's where you'll see arcing. Reverse the order when removing the cables. I believe that's the reason for the "negative spot" you mentioned. This isn't a concern when charging your battery with external equipment, assuming you wait until after the charger is connected to turn it on.
 

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Why though? CTEK comes with conenctors for the battery.
I ordered this extension for 10 euros for easy conenctions:
View attachment 30086
For me, I didn't like having to constantly remove and reinstall the plastic shroud that covers the battery, and then having to store it somewhere while it's on the tender. Also, I didn't want to wear out the clip/attachment points of the shroud either. The cigarette lighter location is easier for me
 

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To reduce the possibility of a spark igniting out-gassing that might be present from a car battery when jump-starting a car with another battery, it's best to connect to the positive terminal first, then connect to a ground point somewhere away from the battery. That's where you'll see arcing. Reverse the order when removing the cables. I believe that's the reason for the "negative spot" you mentioned. This isn't a concern when charging your battery with external equipment, assuming you wait until after the charger is connected to turn it on.
Negative spot is there to protect coulomb counting electronics for the ASS.
 
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