Davel

Here is a strange one. Drove my 03 E to charlottesville, va last monday for work, car sat the whole week and i drove it home on Friday about 200 miles round trip. Did not drive saturday or sunday, went to drive to work on monday and the car was "dead". Used key to open trunk and gave it a jump start. Had an appt already (tuesday) to have an Audio gateway bracket replaced so i asked them to check the battery, the SA said "battery is charged but not fully charged" and $50 to install a replacement. So i decided to drive to work and call roadside since they dont charge to install battery $270.

The tech checked the battery with an electronic device and it showed that the battery was "Good", he said if anything was wrong including a single bad cell that it would not indicate "good" so there is nothing wrong with the battery. Nice guy and gave me a $40 off coupon for a replacement when needed. I asked him to check the battery under the hood, he said that needs to hooked up to the computer at the shop, but that battery only runs the SBC brakes.

Both batteries are the original batteries and the car is now 7 years old (i purchased new), i dont remember leaving any thing on and just about everything turns itself off anyway, what could the problem be ? By the way the car has been fine since i jump started it on Monday. 7 years is the longest i've every gotten from an OEM battery....

amdeutsch

There was an issue with the voltage regulator on V6 models. Might search on here for more info.

vettdvr

I replaced my Main battery with a carquest European direct replacement AGM battery when mine was 7 yrs old. It was still working but on one start gave a battery warning. I just decided to avoid all the hassle by doing a "preventative" replacement. My aux battery was replaced 6 months prior.

AMGSpartan

Hello Davel,

WOW, 7 years is fantastic service from car batteries.

If you are interested in DIY fixes...I just replaced my AUX battery pre-emptively at 5 years with the AGM BS-14 size from Walmart. Fits perfect. You will need a battery charger to give it it's initial charge. The nuts that come with it fit the MB bolts that are captive in the pos & neg terminals.

Davel

Thanks, i noticed we have the same cars except my vette is a 2008, and thats what i used to jump start the E class...

TPAbnz

Same Walmart replacement for me.

Then I saw the same battery for $20 less at Sam's Club: $44.

TPAbnz

That's not really correct. The aux battery provides supplemental power if the main battery voltage is low. You don't need a computer to check voltage. A voltmeter or other conventional tool works.