Battery Source???

[motogman]

I am looking for new batteries for my 72 911. I had used Interstates product but it does not seem that they carry them any longer.

What can anyone recommend?

[boxster03]

I am pretty sure they still do. Model U911. Call the 800 no. on their website and speak to corporate.

[HarryD]

Hi:

Welcome to the best 911 BBS on earth. You should find anything you need to know about your car here.

We usually ask new folks to post pictures so we can see your cool ride. Please!

I used to have the Interstate U911's. They are drop in replacements.

Unless you are doing concours, you might want to consider going to a single Optima on it's side. No fumes or acid leaks. Plenty of Cranking Power.

I also hear that you can use the Miata Gel Cells in place of the factory lead acid battery as an alternative.

You can do a search here and find a zillion threads on battery ideas.

From one thread:

Originally Posted by HarryD

I went with a single Optima.

This thread has a good discussion:
duel battries

My thoughts are:

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 Genuine Parts & Literature - 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.

An Interstate Battery U911 is also an exact fit.

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

Also consider that unless your initials are M.S., chances are you will not detect a handling difference between a single and dual battery setup.

This is another one good one:

Early 911 Battery Options

[geshaghi]

Interstate still carries the correct battery for early 911's. We stock them at our shop and any Interstate battery dealer should be able to get them quickly.

[boxster03]

You would like to think so but I find Interstate has a few problems in their customer service area. As a company they maybe better but I only say this because my Uncle worked for them as a production engineer for 35 years.

[dicklague]

I used the Miata batteries and they are great. A bit smaller than the UA911, but very good.

I did a google search......maybe even eBay.

[vmb]

which miata battery? The Westco? Anyone know the specific part number?

I installed an Optima, but had too much trouble. My Battery Tender couldn't maintain a charge, but mostly the problem is I don't drive enough. Will the Miata battery require a new mounting system?

Thanks

[motogman]

The local Interstate dealer quoted 4 week delivery time. I need to call again but it sounds ridiculas. What Miata and Optimum part numbers are being used?

[Stophos]

When my local Intersate battery dealer told me that the U911 batteries were no longer available I went with Sonnenshein Gel batteries. Purchased them from Batterysales.com I believe. They have the proper battery for the boxes and no worry about corrosion.

[E Sully]

For the dual battery cars the Westco Miata AGM batteries are great. Slightly smaller than stock and no venting or acid spillage. Westco Miata Battery with $14.95 SHIPPING!!

[motogman]

The Miata battery is about the same height and width but about 2 " thinner. What mods did you make to fit this battery - seems a simple fabrivated 'shim' would be effective to use it directly in the existing box and tie downs.

[drm05]

I replaced my 72's with two Odyssey 1) PC 1200 MJT and 1) LMJT (left postive mount) - I have a few pictures posts here.. There is also a XS Power D1200 & XS Power S1200 that will fit great lay on there side.. of whatever is needed..

[Gary De]

I used Sonnenschein DF75's. It,s a German Exide and the fit was perfect. They were purchased from Battery Sales in Miami 1-800-771-2288.

[jetfrank]

Hi all, going through the same issues with respect to batteries..........does anyone know which Optima will fit the battery box - seems as though all the ones I see are too long - I know it goes on its side but none that I have seen are less than 9 inches long and I measure the opening about 8 inches. I have motorcycle bats in there now which have died - I got them at autozone, I'll post the part number tomorrow. I may have to go back to that route or go with the mazda - I'd like to try the single battery agm solution though. Also, VMB, in doing research on gel cells I saw somewhere that regular battery tenders will short cycle gel cells and wind up ruining them..that is, the battery has a memory and thinks its dead when its not (note not I'm not an electrical engineer but I've heard of this happening with cordless tools unless you run them the battery all the way to zero). Someone on another thread from 2008 has a pic of a NAPA side mount battery installed on the pass side with a single battery set up - would love to get the part number of that bat if I can. Meanwhile I will explore the Miata option.......thanks, frank

1970 911 T
1986 928S

[HarryD]

Frank:

From one the threads I posted above:

I put my Optima battery on it's side (with the ground post in the hole).

I used a flat braided ground strap to attach to the factory ground point.

Disconnected the crossover positive lead from the battery post clamp.

I made a hold down with some pipe support strap material. Pop riveted a D ring to one end to hook the strap onto the factory hook in the back of the battery box, bent it around the battery and used the stock hold down bolt to attach the other end to the threaded point in the floor of the trunk.

Be sure to put something to cover the positive battery post to prevent an accidental short or arc.

The end sticking out looks like this:

[rphillips]

I did a very similar Optima on it's side mount. I just remove the wing not of the negative battery cable post when I'm not running her for a few days, keeps the battery nice and fresh.

[cmcfaul]

I just went through this. The Sonnenschein's are a perfect fit, gel battery. They are expensive and mine only lasted about 3 years. The Miata batteries are tiny. The Interstate are the right fit and can be ordered directly from Interstate (local stores don't cary them).

I simply went to a battery store with a tape measure and found two that were the right demisions. Fit like gloves with a small spacer behind them. 50 CCA from two batteries and the hi torque starter.....She fires up in a second.

Chris
73 911 E

[jetfrank]

Originally Posted by HarryD

Frank:

From one the threads I posted above:

ha I had not even thought of putting it in that way---thanks.........just got two Ray O Vacs SL 170s today from Batteries Plus........about 70 bucks each - side terminals so the post clearance is no longer a factor. frank

[abbieinmd]

I would appreciate any kind of input as to where and how much I should spend.

Abbie

[bavaria911]

Interstate dealer in Glen Burnie, MD sold me two for $115 each.