Batteries - 73.5 911T.

[Aircool]

I need new batteries for my 73.5T. This is my 3rd set of Interstates in the past 5 years and am getting tired needing new ones every few years. I have kept them charged in the winter and disconnected them from the car when not in use. I am not sure why I am chewing them up so quickly. The alternater was serviced 7 years ago and is working properly.

Has anyone had good success in the past with other brands? I am interested only in batteries that fit the original boxes.

Thanks,

Steve

[LKreg]

I think Sonnenschein gell cells are the best solution.

[Bummler]

I think Sonnenschein gell cells are the best solution.

Do they fit properly and where does one get them?

I have been using the "Porsche" batteries acquired from performance products. I get about 3-4 years on a set before they go flat. I have a smart trickle charger on them from time to time. I use the Deltran Battery Tender...

[edmayo]

I've been using the sonneschein batteries for about 17 years. They are the only answer as far as I'm concerned. Yes, they are an exact fit, nothing need be changed. They seem to have a life of 5 or so years, but they do not tolerate being overcharged, that will build up too much internal pressure and a safety vent will pop and then it's toast. If you use a charger it must be one that will shut off when the battery reaches full charge. I don't even use one and the car will start even after a month of sitting. You must be prepared, however, to NOT have any more white corrosion or rusted out front pans. They can be purchased at batterysales.com, or maybe it's batterysalesusa.com, forget which.

[sithot]

Do they fit properly and where does one get them?

I have been using the "Porsche" batteries acquired from performance products. I get about 3-4 years on a set before they go flat. I have a smart trickle charger on them from time to time. I use the Deltran Battery Tender...

Stephan has this situation well in hand as the Smart Charger is the best advice you can get. I use these on my motorcycles and get very good service out of my batteries. I've only had 2 in my 11 year old Electra Glide using this gizmo.

Just unplugging them and letting them sit does nothing for the life expectancy.

Good luck,

Tom

[Bummler]

As Tom noted I too use Battery Tenders on my two BMW motorcycles, that was how I originally discovered its great utility after burning through a bunch of expensive lead acid batteries.

My questions is where and how much are you paying for the Sonnenschein batteries?

[ljowdy]

Personally, I believe that if you've gone through 3 sets of batteries in the past 5 years, it's not the fault of the batteries. A new set of expensive batteries installed into a car with electrical issues won't solve the problem.

I'd start checking for short circuits or if something is energized and drawing battery power. That car should only have the clock drawing power. Get out your amp meter and start checking.

My 73.5 had a battery drain that I couldn't figure out. In fact, the charger, on 12 amps couldn't keep the battery charged.

I've converted and only have 1 battery and it's a side post from NAPA that fits the battery compartment. I finally traced it down to a bad electric window switch that was stuck in a semi-on position. (window motor wasn't activated but it was pulling down the battery.

It cost me 6.00 for a new battery and everything has been great since I repaired the problem.

[edmayo]

The source for the Sonnenschein batteries is www.batterysales.com You want the DF-75 w/SAE posts, and the cost is $129.00 I have three 911's with two of those in each car, best money I've spent.

[HarryD]

The source for the Sonnenschein batteries is www.batterysales.com You want the DF-75 w/SAE posts, and the cost is $129.00 I have three 911's with two of those in each car, best money I've spent.

Ed,

What is the difference between the DF 75 you recommend and the A512/40A shown above?

[edmayo]

No difference Harry, they just changed their part numbers is all, DF-75 is the latest.