My battery hold a charge for 2-3 days! It goes from 12.6 v to 9.6 v

 

So, is the battery just bad or is there too much standby drain?

Go to the link below and download V3 of the tutorial and measure your standby current. If it is too high, fix that. If it is to specs, replace battery.
https://www.crossfireforum.org/forum...lp-papers.html

 

Oh, one thing. While I STRONGLY recommend you find out exactly what the current is, if you want to take a wild (lazy) guess, just disconnect the alarm siren, it has become a leading cause of dead batteries.

Remove the cover under the wipers. All those screws must come out, removing the wipers is probably a good idea, but you might be able to bend the cover up enough and get in there - the siren is near the middle of the car and has a three-wire cable going to it.

 

One thing. If you want to take a wild guess and be lazy - just remove all those screws from the cover under the wipers, bend the cover up, and about midway between the passenger side of the car and the middle of the car, is the alarm siren. Unplug the three wire cable going to it and see if that fixes the problem.

If so, leave the thing unplugged, if you want an alarm siren, order a new one.

 

How old is your battery? An old battery beyond its service life won't hold a charge either. One option is to pick up a float charger (e.g., Harbor Freight) and keep it plugged in when not in use. But if it is a new battery, then something is draining it and needs to be found.

 

I have same problem with my 2007 crossfire. Battery goes dead after 5 days of non use. A real pain. The battery is 1 year old. Bringing it in with forum printouts because these boneheads at Chrysler dont know what they are doing with crossfires.

 

Good video on checking for voltage drain, also on a R170. He also does a nice video on the Crossfire. If you have a battery/drain issue on your Crossfire, this is a great video that likely applies to your issue....

 

One problem is you don't have a Chrysler, you have a Mercedese SLK 320.