aznmode

My battery dies overnight or sometimes a few hours. I first noticed it after a car wash a month ago. They had to jump it. Next was about a 2 weeks ago when I was updating the maps it died after 20 min (engine off) and had to jump it. Then yesterday before I left for dinner had to jump it again. Drove about 30 min to the restaurant then 2 hours later had to get it jumped again. This morning the same thing. Would a disconnected trunk light do it? Also my window control lost the 1 touch auto close feature. I don't see how those 2 could drain battery. When I go into engineering menu it has a bunch of low battery warning with voltage going down to about 9-10v

RavenMDX

Yup had exact same issues last year. Time to get a brand new battery. after 3-4 years, the battery needs to be changed.

I am now using an Interstate Mega-Tron MTP (recommended)

P.S.: don't update maps on battery power alone. Either drive the car during the map updates or get a professional battery charger.

aznmode

I took it to the dealer and they said the battery doesn't hold charge so it does look like a battery issue. I got charged $252. $165 for the battery and the rest labor after 15% discount. How much did you buy your battery for? I was going to try to do it myself but I don't know of a way to do it without losing the programming on my car. If you swap battery the car needs to be reprogrammed so I figured the dealer would be my best bet.

I thought our battery is supposed to last 8 years. I'm surprised yours only lasted half that. Mine's almost 6 years old.

RavenMDX

The price you got charged for the battery is about right. No worries.

8 years? hehe not in our benz..too many modules/tech. Your lucky it lasted that long

boom132

Isn't there a little 9volt battery device you can plug into the cigarette lighter to keep "voltage" in the car while you are changing out a battery? I've seen that somewhere... not sure if applicable in our vehicles.

aznmode

That would be cool.

C300CA

To do that, key should be turned to the first stop (accessories?). Otherwise the 9V battery is not connected to the main power.

Carsy

Just a thought.... having the key on accessories may expose your car electrics ie sams to voltage spikes when changing the battery.

If the key is off & withdrawn is there less likely hood of this happening ?

NewtwoMB

Just another side to this battery issue - 5 years and 2 months on the original OEM battery - and it even held its charge while I left for 5 weeks at home late last year while we were on vacation in Australia!

Used most days and have the auto headlights on 24/7.

Just my 2 cents....

boom132

Original battery on my 2010 as well... I did have to put it on a charger once; overnight. With the freezing below zero Maine winter I've been having, the car has started every morning... pretty impressed with this particular battery so far.

C300CA

Good point. I think better way is to connect a charger directly on + and ground terminals under the hood, or wire them into the cabin for 9V connection if parking on the street.


I have a trickle charger and I charge the battery whenever battery reading is 11.4V or below.

aznmode

Nice! How many miles do you have? I have 61k. The dealer told me it was probably due to the number of starts that car had. Not really sure that validity of that but I'm the 2nd owner so I'm not sure how the car was used prior. But I've own a w203 that I had for 6 years and did not replace the battery on it. Traded it in last year so I'm not sure if it's still going.

NewtwoMB

Thanks - I have 59K miles on it now - most of those were done in its first 2 years as I was doing a lot of traveling around the UK and Europe. It'll get another 3000 this year as we're going to the south of France in it in the summer. Great car and looks as good as new (better even as the paint has had a lot of extra care and attention!).