71 Porsche 911T 2.2 Battery Question

[BillyT]

I am working on starting a 71 911 2.2 that has been in storage for years. My question is the car has two batteries is there anyway I can rewire and use one battery? if so a point in the right direction would be greatly appreciated.

Thanks,
________________

Bill

71 Porsche 911 T 2.2
05 Saab 9-3 Convertible
Dufour Gib Sea 37 Sailboat

[ossiblue]

Relatively simple.

Remove the passenger side battery. The heavy black cable now must be safely insulated from any ground (sheetmetal) which can be done by wrapping the end with rubber and securely taping the wrap to the cable, or use nylon ties to bend the cable back on itself--anyting to guarantee the end will not ever make contact with a ground. Or you can disconnect and remove the cable from the connector on the left side battery--that is the safest way.

Remove the left side battery and buy a larger single battery that has enough power for the entire system. You will have to fabricate a hold down system outside the battery box as the larger battery will not fit. There are several threads in the Tech fourm which describes how others have secured the battery to a plastic cutting board which is bolted to the trunk floor.

Technically, it's not difficult and many have done it--even putting the battery in the smuggler's box. Try a search, or maybe someone can post a link to a thread that runs through the conversion.

Here are some links:

Early Dual -> Single Battery Conversion

converting to a single battery

Dual Battery Questions - Help!!

Share your LONGHOOD battery mounting solutions.

[BillyT]

Thanks ossiblue, I will check the forums for manufacturing a new battery tray

Thanks,
________________

Bill

71 Porsche 911 T 2.2
05 Saab 9-3 Convertible
Dufour Gib Sea 37 Sailboat

[Flat6pac]

On the left side you can remove the black wire on the positive battery terminal that runs behind the fuel tank. Than completely disconnects the right side.
In years past..we would get the battery for the VW bug that goes under the rear seat and use that for the left battery and the ground side would slide in the battery box.
Bruce

[HarryD]

Originally Posted by BillyT

Thanks ossiblue, I will check the forums for manufacturing a new battery tray

Thanks,
________________

Bill

71 Porsche 911 T 2.2
05 Saab 9-3 Convertible
Dufour Gib Sea 37 Sailboat

Bill,

The battery tray the '74+ cars can use does not work for us dual battery guys. Of you go the Optima route, you can put the battery in sideways into the left hand battery box and make a strap.



My story here: duel battries

[BillyT]

Thanks for the link HarryD, I will set out this weekend to shop for a battery and then build the housing. I have some really good ideals thanks to you guys on Pelican.

Thanks,
________________

Bill

71 Porsche 911 T 2.2
05 Saab 9-3 Convertible
Dufour Gib Sea 37 Sailboat

[HarryD]

Originally Posted by tuned6

Hi. I just got A new '72E. I was just browsing and came upon the thread. Why is it that you guys don't want to use dual batteries? Is it so you can buy them at walmart or is there not a source? I'm early into this new topic, is there a source for the dual batts?

Tuned:

Good question.

Well for us with Dual Batteries the "standard" groups do not fit so you are limited in your selections. There is no reason not to have dual batteries if you so desire. For me, the cost of one larger battery was significantly less than two properly sized ones. From an earlier post of mine, the story boils down to:

The cost of a lead acid battery is less until you consider the cost of a front suspension pan replacement from a boiled over or cracked battery.

From another post (duel battries - Pelican Parts Technical BBS

Originally Posted by HarryD

Paul is correct, Sonnenschein is the way to go to keep the factory set up. You will need their DF75 (A512 /40 A) gel cells - Wholesale Battery Distributor - Retail Battery Distributor.

An alternative is go with a single Optima on it's side in one of the boxes and disconnect the excess wire.

Also, you can get the exact fit lead acid style ones from your Porsche dealer (New Editions - Classic Catalogues - Porsche Classic - Dr. Ing. h.c. F. Porsche AG). Look for: "Battery 12V 36Ah for the 911, Model: 911, Model Year: 1965-1973, Part number: 999 611 014 91, Availability: 01.03.2009". Pelican lists them at $189/ea and a special order.

Here in the states, an Interstate Battery U911 is also an exact fit.

There are other options such as Miata, Oddessy or Stinger batteries as well.

FWIW: I went with a single Optima.

Do a search, you will find numerous ideas.