daking1959

Greetings..
Over the past couple of weeks ,Ive noticed my CLK has to make a effort to start.
It sounds like a weak battery. I had this battery put in by the local dealer in March 2014.
I went to Dyno mode, when the car does start, it shows 11.5 volts, but jumps up 14.2 volts before the car comes to its idle RPM.
My question is , 4yrs normal life span for a Mercedes battery.
Ive seen some posts on there being a problem with batteries being drained from electrical issues.
Any guidance would be welcome..
david

Rudeney

11.5v is too low. It probably is time for a new battery. The MBZ batteries used to last for may years, but lately, they seem no better than most, which is about 4 years.

daking1959

Many thanks Rodney..
Have you got a battery suggestion?
Any tips would be welcome as well. My car is a cabriolet.
D

Rudeney

i have been buying the Advance Auto Platinum AGM batteries for all my MBZs. You can usually get a 20% discount if you order online and pickup in store. Some stores will install it for you, other will say "we don't mess with them Muhr-SAY-DEES". They have a full 3-year replacement warranty. The one I had int he C-Class lasted well over 5 years and it did a lot of sitting unused.

zmmanley

Check out a "Bosch Premium AGM". I have two CLK's and replaced both batteries.....$175/ea. at Pep Boys

FYI....the OEM batteries in both cars lasted over 10 years..."that was then...this is now"

mcgsxrclk500

Does hooking the car up to a battery tender extend the life of the battery?

Obviously not great for a daily driver, but I tend to use mine 2-3 times a week. I have been hooking it up to my battery tender every 3 weeks over the summer. It usually shows a full charge after about 3 hours and then just maintains that until I pull it off and drive the car again.

zmmanley

A battery tender will extend the performance of the battery since it will maintain a charger that prevents the battery from sulphating (see link)
https://batteryuniversity.com/index...._to_prevent_it

Battery sulphation:
What is sulfation? During use, small sulfate crystals form, but these are normal and are not harmful. During prolonged charge deprivation, however, the amorphous lead sulfate converts to a stable crystalline and deposits on the negative plates. This leads to the development of large crystals that reduce the battery’s active material, which is responsible for the performance.

Sulphation is accelerated when the battery's charge drops below 12.5 volts.

I don't know if AGM batteries are less effected by charge depletion. The claims are that AGM batteries can be recovered more frequently from significant discharge then conventional lead acid batteries.

For the price difference....the benefits favor replacing with an AGM.

zmmanley

AGM vs. Flooded lead acid battery:
AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary. The battery stands up well to low temperatures and has a low self-discharge.

daking1959

thanks to all..
I put a Advance Auto Platinum AGM battery in the CLK..($209.00 after discount and core) I put it in myself.
The battery is heavy and your working in a pretty tight area, it went in without to much of a fight.
The tray was very clean, and I did have a small spark, when hooking up the last cable (-) , which I expected.
The only thing I had to reset was the clock, and my settings on the radio. ( the HK system sounds so much better than some Bose system to my ears)Ill sit in the car just to listen to David Gilmour play Sorrow..lol
It was a good project..thanks to all for the guidance,
post script.Thanks Rodney when it come to a Mercedes , Theres yourself and other members, and Google..Thats why If I need some help with my Murh- Say- Dees..ill enjoy our Forum

faded1004

which battery number was the advance part number? i want to save it for reference...

Rudeney

For future reference (or the next guy changing a battery), raising the hood to the Service Position makes the job easier. To do this, press the red button on the left side hood strut and then lift it to the full 90-degree raised position. To lower it press the button and drop it back to "normal open" and then close it as usual.