Battery tender

356 Porsche-related discussions and questions.
Post Reply
Message
Author
Hart Bochner
356 Fan
Posts: 17
Joined: Fri Jun 16, 2017 8:50 am

Battery tender

#1 Post by Hart Bochner »

Anyone tried a battery tender that plugs into the cigarette lighter?

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: Battery tender

#2 Post by David Jones »

I use one on my 97 boxster. I found out the hard way that if on the 97 the battery goes flat you cannot easily open the trunk lid because the lock is electrically operated. Only option other than the not so easy mechanical shenanigans is to charge the battery through the cigarette lighter which fortunately is always live.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

Hart Bochner
356 Fan
Posts: 17
Joined: Fri Jun 16, 2017 8:50 am

Re: Battery tender

#3 Post by Hart Bochner »

I have a 356, wondering if it’s always live

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: Battery tender

#4 Post by David Jones »

Depends on where the power is taken from. Originally it was from fuse #2 which was always live but it could have been changed so test it with and without ignition turned on.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
DonCichocki
356 Fan
Posts: 521
Joined: Thu Aug 22, 2013 4:29 pm
Location: Lafayette, NJ

Re: Battery tender

#5 Post by DonCichocki »

I've used a 6V Battery Tender brand through the cigarette lighter for over 4 years with no problems. I'm using a 6V Optima battery. Car is a '65 "C".

User avatar
Bruce Smith
356 Fan
Posts: 1624
Joined: Sun Jun 19, 2011 9:47 am
Location: Rochester, NY
Contact:

Re: Battery tender

#6 Post by Bruce Smith »

Dave - I owned a 2002 Boxster and had this problem once. I don't remember all of the details but a procedure is described in the manual on how to apply power near the fuse panel to get the trunk to open.

I now use a through-the-lighter style on the new 911, it seems to work fine. I'd wonder about the wiring resistance in older cars. I go directly to the battery with a float charger for these.
Bruce Smith

User avatar
Al Zim
356 Fan
Posts: 4304
Joined: Thu Mar 27, 2008 12:37 pm
Location: FT.WORTH/DALLAS TEXAS
Contact:

Re: Battery tender

#7 Post by Al Zim »

I have used the power point socket on my 1961 car to charge the battery. Zim's sells the adapter, unfortunately it is not reasonably priced! at $46.50. al zim 800.356.2964 al zim
Last edited by Al Zim on Wed Jan 03, 2018 3:02 pm, edited 2 times in total.
www.allzim.com 
356 Parts and Services
www.facebook.com/ZimsAuto/
www.instagram.com/zims_autotechnik/

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: Battery tender

#8 Post by David Jones »

Bruce, even with old wiring a battery tender connected through the cigarette lighter socket should be quite safe as the output of the battery tender is only going to be around 2 amps at most. I think the heater element of the cigarette lighter used more current than that. By the way my 356's have a pigtail which is supplied with the maintainer connected to the voltage regulator for maintenance charging. Easier than getting to the battery up front and a good reminder to check the oil and general look around when I unplug it before driving.
For those wanting an adapter to plug into the lighter socket here is one on Amazon. I will order one for myself because the one I bought 10 years ago is only about 8" long.
https://www.amazon.com/Cigarette-SinLoo ... B073WW13PF
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
Bruce Smith
356 Fan
Posts: 1624
Joined: Sun Jun 19, 2011 9:47 am
Location: Rochester, NY
Contact:

Re: Battery tender

#9 Post by Bruce Smith »

Dave - Not so much concerned with current overload on wiring but instead the resistance to the battery. Cheers.
Bruce Smith

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: Battery tender

#10 Post by David Jones »

I understand Bruce but the line from the lighter to the socket is directly from fuse #2 and directly from fuse #2 to the battery the other direction so only one intermediate connection. Check those two for cleanliness and corrosion and you are ready to go.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

James Watters
356 Fan
Posts: 361
Joined: Tue Apr 08, 2008 4:51 pm

Re: Battery tender

#11 Post by James Watters »

Had a Porsche cig lighter on m 997 over the winter. Car was covered with the windows rolled up and the hood down. The tender died sometime that winter but because the cover was on,I didn't know it. Let's just say that the days of electronic locks and switches made getting into the car very difficult. I use a Deltron battery tender now that sit's on the outside of the car so I can see the light.
59A Coupe
64C Sunroof

User avatar
Charles H Jacobus
356 Fan
Posts: 493
Joined: Wed May 28, 2014 5:02 pm
Location: Dallas, TX

Re: Battery tender

#12 Post by Charles H Jacobus »

My '65C is always live but you could check it with a multi meter. I use a NOCO and this inexpensive one has good health software in it and kept my 6 volt alive even though it is quite inexpensive. If you want to put it in the charger you can use the extension Dave is talking about and get an SAE connector.
https://www.amazon.com/NOCO-G3500-Ultra ... arger&th=1

I also use a NOCO 3500 for the 993 because you need the extra power for all the security and other equipment running when the car is off. The .75 amp does not work on that one.

Chuck
Current:
2012 Silver 991
1995 Midnight blue 993
1965 Red 356C

Past:
Fond memories of 14 others (including a '63 Normal and a 61 S90) :)

Art Kendall
356 Fan
Posts: 62
Joined: Sun Jul 05, 2009 7:12 pm
Location: Vancouver, BC, Canada

Re: Battery tender

#13 Post by Art Kendall »

Charles H Jacobus wrote:My '65C is always live but you could check it with a multi meter. I use a NOCO and this inexpensive one has good health software in it and kept my 6 volt alive even though it is quite inexpensive. If you want to put it in the charger you can use the extension Dave is talking about and get an SAE connector.
https://www.amazon.com/NOCO-G3500-Ultra ... arger&th=1

I also use a NOCO 3500 for the 993 because you need the extra power for all the security and other equipment running when the car is off. The .75 amp does not work on that one.

Chuck
I also purchased the G1100 a few weeks back, and I have found this to work amazingly well. I can keep the main charging unit attached to my wall near the car and can always view the status. The best thing is being able to remove the battery clamps and attach the ends directly to the battery terminals. There is a quick release with a short cable that is permanently in the car, and I store it behind the spare tire. Makes it so easy to disconnect or hook up as needed. Works great and the car started immediately after not running for 2-3 weeks. Not like the old style charger, heating up etc...great technology and very reasonable.
Art Kendall
Vancouver, BC, Canada
63 B sunroof coupe
#124949/ivory/black
Member 17242

User avatar
Jay Wiener
356 Fan
Posts: 572
Joined: Thu May 31, 2012 1:27 am
Location: Los Angeles
Contact:

Re: Battery tender

#14 Post by Jay Wiener »

The only problem with letting my 356s sit is that the carbs dry out and you will waste your battery getting them to fill up. The simple solution is a little gas in a water bottle to feed into the carbs and waa-la!

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: Battery tender

#15 Post by David Jones »

Jay, the problem with that approach is that you have to remove the air cleaners. The priming pump whether manual or electric is a better answer but I prefer to give it full throttle and spin it over until I have oil pressure then a dozen pumps and it usually fires right up.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

Post Reply