purplegrog

I recently took my car to Autozone to get the battery tested (I posted recently either in this thread or the tech talk forum about the car dying on startup) and their tool reports the battery tests bad. at the time I was being lazy, so I had the guy test using the positive and negative leads in the engine compartment instead of opening up the rear bench and connecting the tester directly to the battery. Will testing in this manner yield erroneous results? I was going to get it tested today connecting directly to the battery leads, but it was raining and they wouldn't test it unless I disconnected the battery and brought it inside. :-(

sosh

To get an accurate reading it should go directly to the battery and should be a load test. Just putting a meter on it will not give true condition. A specific gravity test of each cell should also be done.

RobertG

places like Auto Zone and R & S Strauss have these little handheld battery testers that they use to judge batteries which I don't think that they are accurate .If your battery is on the old side like 5 years plus then I would say that you should start thinking of replacing the battery. To add to that get the battery that belongs there ,not an aftermarket kind.The farther away from the battery you test then you must take under consideration the amount of extra wires ,which will add resistance to the circuit and that might fool the test equipment and then you get incorrect readings.Battery testing should always be performed on a fully charged battery at the battery.

Start battery testing following these steps;

visual inspection

specific gravity test of the electrolite

load test (half the cold cranking amps for 15 seconds)

E-Klasse

Does you starter crank over fine or is it slow?

Test your alternator as well. Mercedes can have a strange starting problem when the voltage regulator in the alternator alows to high of voltage to the system. You can actually be over charging your battery this way as well and cause it to fail sooner than it should. The engine idle speed control module can't handle a voltage spike. The engine starts and dies right away because it will not maintain idle.

Air Marshall Eldritch

I will add that the MB battery for the W210 is a monster. Much larger then any Sears battery. Twice as expensive too, of course. But if replacing one (my first one died at 3 years, my second is going on 4 years strong), get the OEM one.

E-Klasse

Sears makes a EURO battery that fits in a Mercedes. The battery in the E-Class is under the rear seat so you want one that has a vent tube. I have had an Interstate battery for 4 years now too. I have also seen one from AC Delco that are lage enough and for the european cars. Most are about $100 or more.

michakaveli

If I can add my 0.02 as I just replaced my battery. When I bought my car end of '02 I had to replace the battery also. I bought an Interstate (MTP93) from my local indy. The battery I bought would hold a charge, but would not cycle as fast as I thought it should. I figured since I have the diesel and it drains so much power when starting that it must take a while to recharge. Nonetheless this past week my battery totally quit while getting my tires replaced at Sams. I know I have completed drained this battery at least 3 times, from the time I had bought it. This battery still lasted me over three years and never quit. I bought a replacement battery, same model and the charging system maintains a nice and steady high voltage (low 13's high 12 w/ accesorries), higher than on the old battery and cycles much much faster.

Moral of story, although the battery I bought over 3 years ago was a def unit, it still had the stamina to withstand at least 3 deep cycle discharges, down to 6 volts mind you (verfied via climate control panel selection 24). Don't know if the OEM would withstand that torture, but I feel the best "aftermarket" alternative to the OEM is the Interstate. And I'm sure it is cheaper than the OEM. Also the Interstate is also vented just like the OEM. The Interstate warranty also is tought to match. If my battery fails within the first 18 months, I get it replaced without any additional charge. Does the OEM have that for a warranty?

purplegrog

update:

I've been able to narrow this starting problem to a strange quirk. Almost every time I start the car, the car will die *if* I have the climate control system on, regardless of the fan speed. if I first turn the climate control off prior to starting the car, the car roars to life with no problem at all. anyone have any ideas?