STOP....do not use a cheap battery charger on these vehicles! After a bunch of research, it seems cheap chargers are just that....cheap! You run the risk of them malfunctioning and frying your battery and/or electronics.

MB approved chargers are made by CTEK which is a Swedish company that manufactures chargers. CTEK makes a lot of different models and you have to make sure and get one rated to handle the large batteries our diesel's have (> 95 Ah).

I found this one to be the correct size and this was the best priced new one I could find after going to a bunch of sites (seller also shipped it quickly):

CTEK charger suitable in size for our MB diesel batteries: MUS 4.3

This charger comes with two connection method's: clamps and eye rings. For the E320 CDI (or any vehicle with difficult to reach battery in trunk), I recommend hooking up the eye rings to the battery post bolts and snaking the wire out to a convenient place in the trunk. You then just connect the charger to the wall, connect the charger to the connection point (after removing the rubber protective cap), and then set the charger to charge.

Warning: do not run the "Reconditioning mode" with the charger connected to a battery and vehicle due to the higher voltage used. The newer diesels have very sensitive electronics and electrical systems! This mode might shorten the life span of electrical system of car.

The CTEK unit I purchased is very well made and thought out. I can see why MB approves of these!

The newer MB's use quite a bit of energy even when not running and this puts a lot of strain on the batteries. If you leave your newer vehicle for any length of time, using one of these occasionally or leave it on while in storage. Makes a lot of sense. You will be rewarded with a car that is always ready to start and you will get longer battery life.

Since I leave my CDI stored in the winter and it is cold here, I think this charger will pay for itself the first year of ownership.


-- Chris

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-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991