BIG-BRO

If you are going to try to charge/maintain a Porsche OEM battery, also be sure to verify battery "fluid" electrolyte level...... I had not had a battery go low in so many years that I forgot to check. I knew it was getting weak after sitting and I was plugging in the maintainer and/or charger. After I swapped it out, I removed the six little caps.....wow.... look I can see bare plates..... Obviously that's going to kill it real quick.....

Thaddeus

Thanks! I have my weekend project now.

chris walrod

I agree with the five year rule -- but extreme climates may require three year replacement intervals. As Bull said, depends on typical useage -- I believe daily driven batteries will last longer, possibly the full five years or beyond.

I had a Mercedes E class that would eat batteries about every two years -- and those are freakin' tractor batteries!!

Bull

Also proving that it depends on many things, including the car. We have an E Class that is also going into its 8th year on an Interstate battery. The car has never been on a battery maintainer and is my wife's driver, with about 6k miles per year.

Terry Adams

About 5 years.

endodoc

The 75/35 is now called the 75/25 for dome reason