2005 Mercedes-Benz CL65 AMG: A Dead Battery Stops Even the Most Powerful
June 3, 2014
"It'll be fine."
This was me telling my wife about leaving the long-term 2005 Mercedes-Benz CL65 AMG parked at the airport while we went away for a trip. Originally, a friend was supposed to give us a lift. But he couldn't at the last minute so I decided we'd just take the CL. It did seem a little undignified to leave it parked, but I also considered that it's a nine-year-old car that Edmunds bought for less than $40,000. Plus, nothing can break on it if the car's just sitting, right?
Famous last words.
My wife and I returned from our trip late at night five days later. I knew something was amiss as soon as we approached the car. Nothing was happening when I pressed the key fob's unlock button. I pressed it a few more times. Nothing. My wife just gave me a look. "See, just like I said, it'll be fine," I told her.
Our CL65 AMG has keyless ignition and the electronic-style key, so there's no immediate way to just unlock the car. But I knew that the fob would have a hidden metal key that can be used to unlock the door, so I did that. And sure enough, there was no power whatsoever in the car. The battery was completely dead.
It was too late at night to do anything about it or get a ride home, so we just got a taxi ride home. I figured I'd deal with the CL65 the next morning. But I was a little concerned since I parked the CL65 head in, and I wasn't sure how I'd get jumper cables up to the engine bay (more on that shortly).
To play it safe, I just called a tow service and met them at the airport parking lot. I had a bit of time before the service arrived, so I checked the CL. It turned out that the battery was actually in the trunk. I was annoyed at myself at that point for not bringing my jumper cables and doing it myself, but at that point the tow service was already there.
Actually, it was just a guy in a Nissan Versa. He hooked up a portable battery jumper pack first and we tried starting the CL65. There was some power but it didn't seem like the portable pack was powerful enough. So we hooked up jumper cables from the Versa to the CL as well. The CL65 AMG's V12 came to life. Success! He figured the age of the battery (four years old), the days of parking and the 100-degree heat all conspired to kill the battery.
The CL65 seemed fine, and we both agreed that we should keep it running for 20 minutes or so. I figured I'd just drive it straight home. On the way I was feeling pretty good. I thought about how my wife had asked me to pick up some groceries since we had been out of town. "Well, the grocery store's about 20 minutes away," I thought to myself. "That should be enough time for it to recharge the battery."
After shopping, I came out of the Whole Foods parking lot with my groceries only to find the CL65 dead again. And it wasn't just mostly dead. It was completely dead just like it was at the airport. Even the doors wouldn't unlock. Sigh.
Thankfully, one of the employees at Whole Foods said he had some jumper cables in his car, and he offered to give me a jump. (He even put my cart of groceries in the store's cooler while we worked on the car. Nice guy.) We hooked everything up and...no luck. There was power but the V12 wouldn't turn over. We tried idling his car about 10 minutes for more charging, but still it didn't seem to be enough. Finally, I just called the tow service again.
This time it was a real tow truck. But we encountered the same problems as before. The V12 wouldn't turn over, even after keeping everything hooked up. Finally after about 30 more minutes the tow driver suggested we double up. I found my Whole Foods friend and he kindly brought his Altima over again. With both the truck and Altima hooked up, the CL65 finally started.
I was relieved. I drove it straight home and parked it. I knew I'd need to get a new battery. More on that in the next update.
Brent Romans, Senior Automotive Editor @ 63,954 miles