911 Batteries

[DonMc]

I have a 73 911e, which has the 2 battery system. The batteries are old and one no longer holds a charge. What are good replacement batteries for this model year 911, and where's the best place to get them? I've checked 3 Porsche dealers in the local area, and they ahve to special order them with prices ranging from $70.00 to $140.00 each. Thanks.

[Early_S_Man]

A 'Group 41' or 49 battery from Wal-Mart or Sears, or K-Mart can replace both batteries ... either is the proper 'low-profile' to fit into the battery box, but due to length, part will stick out and require relocation of tool kit and charcoal cannister; disconnect the positive lead to second battery aqnd you are set to go!
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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[This message has been edited by Early_S_Man (edited 10-22-2001).]

[Rich911E]

I just converted over to a single 12 volt battery and used side terminals rather than the top terminals. It works really well.

There are a couple of ones that fit (I currently have an Exide but I forgot the number but will check when I get home and repost tomorrow. You have to "persuade the bottom lip of the battery box a little bit to make things slide in easily, but it certainly simplifies matters. Plus, only one battery makes life easier and less expensive.

I'll try to take a picture and post it tomorrow.

Rich

[2.7911E]

Is there an Optima size that will work? Michael

[GregS]

Don, about a year ago, I replaced the batteries in my '73T with Interstate U911-50's. I believe they were about $64 each. They replaced similar ones that were over 5 years old. I had them tested the other day and they tested out as essentially brand new. Good luck.

[john walker's workshop]

i second the interstates. they're made for early 911s only. you can get the original holddown straps on them too.

[pwd72s]

John & others...Sonnenschein of Germany makes a "dryfit" gel-cell that is the exac size replacement for the original dual batteries. Known as the #A-200, (081-9640)
Easily obtained in europe, $pendy as all get out here. But, I've been running them with good results. On my 2nd set. 1st set lasted approx. 7 years. I found a local battery store that could get them for me, but you might want to check all your local battery sources first. IF you're willing to pay a bundle for 2 batteries, e mail me...I'll give you my local source. Okay, I'll admit it, paid around $400 for the pair. I'm too paranoid about battery boxes & corroded stuff. But now no fear of leaking acid, gasses, eaten carpeting...guess I'm willing to pay the price in order to keep these all original goodies indeed all original. Liquid battery acid sloshing around up there never did appeal to me, and I didn't like the way the sideways mounted optima looked.

[Jdub]

Do yourself a favor when you replace your batteries and test your alternator output at the battery terminals. It is a really good idea to make sure that your alt and regulator are in top condition so that they don't fry your battery investment.

Jw

[cds72911]

Hi my local Interstate dealer stocks an early Porsche replacement battery, he said he sells about 2 pair a year. I think it was about $150 for the pair and they fit perfectly in an early car battery box.

I've never used them, so I can't comment on how well they work.

When I purchased them I had planned a stock restoration - they'd be perfect. However, now that I have bastardized my '72 (3.0 with carbs) I wish I had just bought an Optima for the smugglers' box...

Charlie

[Oldporsche]

I believe that the series 42 is the size that has been previously referred to. It is really the old volkswagen battery. It is the correct height but too long. Thus one end sticks out of the battery compartment.

I know that the size 58 will fit however you should add some insulation to the hot terminal of the battery if you use them. They were the original size for the original Ford Fiesta.

Interstate Batteries can supply the correct size and replacement for your car if originalty is desired. I believe that the Optima has to be mounted on its side to work. Interstate also distributes the Optima. With them you can try several combinations to see what works best.

As previously stated, there are several side post mount batteries that will fit in the boxes without a problem. I am going to try to fit a Wal-Mart DT3 in a '70E tonight to get an idea of how it will work. This battery has both side and top mount posts. I am currently using one in a '75 with good results. This however is a single battery car.

Good luck,
David Duffield

[Allan Broadribb]

I put an Optima battery in my 70-911E last year and I'm very pleased with it. I installed it in the driver side bay on it's side and made a new tie in strap. I guess if you are a perfectionist you won't be happy about not having the battery weight evenly distributed. The up side is looking at your battery a year later and there is not even a trace of that white corrosive stuff. I think you'll find the batteries plus web site has a 10% coupon which will get the price down to about $110.

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Allan Broadribb
'70-911E, 2.2l with Webers
http://www.cheaterswayside.com/uploads/Mvc-002s355.jpg

[DonMc]

Thanks for the battery info - I'll probably get the Interstates.

[radcon]

I'm not too familiar with the older 911's. What was the reasoning behind having two batteries? Seems like added weight, replacement cost, more wiring, etc. When I needed a new battery for my '80, looked for replacement and they said they could special order one that is only for 911's and would cost about $110-130, depending on which parts place I went to. Armed with only a tape measure, I found a common size battery that was smaller, had more cranking amps, and you guessed it - was a lot cheaper. I think it ended up costing me around $60. I guess the lesson is, unless your out to maintain the original look of the vehicle, there are a lot better batteries to be had for less money and less weight.

[Oldporsche]

There were several reasons that the twin batteries were used.

You could get a lot of capacity with two batteries. In the position they are in, they don't take up much space. MG used this system also. Weight distribution was another. Previous models of Porsche actually had weights attached to the back side of the ends of the front bumpers.

Actually I think that the size was descided upon much earlier. You will find that this size of battey is very common in the 6 volt variety. It would be very easy to wire them in series to get 12 volts.

Like a lot of other things Porsche, they present their own peculiar problems.

Good luck,
David Duffield