Hello all you experts.

I bought a new to me 2004 cl500 last year, loving the car, but did not drive and stored for the winter, When I went to start today and get the car out of my Garage. I did not realize the battery in the trunk problem, the battery was dead and I couldn't open the trunk, I did figure out the passenger side floor where I could access the Red battery cable and put some voltaGE to it and pop the trunk, I did get it started with a jump box after I tried for a little while using a charger. I had it running for about an hour, but as soon as I shut the car off and tried restarting , It was dead again. I certainly dont think I have a alternator issue, as I certainly thought running it for a hour would charge the battery.
?? It has a Mercedes battery in the car, do these batteries take a long time to charge. The other issue was the heater was cranking heat I could not shut it off. Was it doing this automatically because it was running in the garage and generating alot of heat. ?? I could try and test voltage on Battery once I get it started again to see if the alternator is charging.

Im very surprised the car would not be charged enough after an hour off running.

Any help or comments is appreciated. I was hesitant to put my charger on engine start mode , because of what about the spike in amps going through the system.

 

If the battery was fully discharged, it may not recharge just by letting the car run. It may be able to be brought back by a high frequency charger, or it may just need to be replaced.

 

Either take the battery out of the car and charge it , or just put in a new battery

You cannot store a w215 for months and expect to start. It will drain the battery without a battery tender /trickle charger . It's also terrible for the abc system .

These cars need to be driven at least every 2/4 weeks

 

^^ What they said.^^

Your battery is probably toast. HVAC may need to be reset like the windows and sunroof Do a search and you should find the reset procedure.