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Mercedes w220 s350 4matic 2004 battery probem... need some help
Hello everyone Im new here and my english is not very good, im sorry if im not writing correctly.
I have a problem with my s350 w220 model... is did change it with new one and after few days it was dead again.. im trying to find is there second auxiliary battery located i the car. Is any one had same problem?
Some where i did read something about car sleep mode,and that can be battery killer if not go off when the car is off..
Im waiting for yours experience and any information is good to know...
battery drain is common problem on these cars . It’s usually the radio /nav system not shutting down . Take out the nav cd and shut the car off see if that helps
I am new member and was trying to find threads or information on how to trickle charge the W220 battery (that is in the trunk). Some posts say that the battery needs to be disconnected while another gives the following instruction that I will cut-paste below. I wonder if anyone has tried this and if so, are there any pictures or instructions as to how a W220 battery can be charged when the car isn’t being used regularly.
Charging from Inside the Engine Compartment
Remove the lid from the Right (Passenger side US, Drivers side UK) fuse box.
Connect the negative lead from the charger to the earth point just in front of the fuse box (or any good earth).
Connect the positive lead from the charger to fuse f33, 40A, that one runs air conditioner and blower motor and is constantly live (at 12V).
It may be too difficult to connect to the terminal on fuse f33, 40A. If so get a spare 40A fuse and solder an extension lug onto one of the terminals. You may need a couple of goes as the heat from the soldering iron tends to melt the plastic. Use a spare so that if you damage permanently it you will not be stranded.
Here was a post on instructions on how to check battery drain on W220 models.
Checking Parasitic Battery Drain
If you find that the battery is constantly going flat or the unlocking system seems to take a long time to respond, it could be that you have a low voltage battery caused by excessive quiescent current draw. The W220 is particularly prone to large quiescent current draw, often called parasitic current drain through it's proliferation of electronic circuits some of which are constantly activated. Sometimes the electronic circuits can develop issues and become heavy continuous users of battery power. When the car has been locked and has fully gone to sleep (takes at least twenty minutes) the quiescent drain from the car battery must not exceed 0.05A or 50mA.
Follow these steps to test the current draw of locked vehicle:
1. Close the trunk lock latch to fool the car into thinking that the trunk is closed.
2. Lock the car. If you have keyless-go don't keep receiver close to the car otherwise car might not go to sleep.
3. Using a clamp meter that can measure small current (CEM DT-337 is one of such meters) clamp the positive or negative lead of the battery.
4. Right after the car is locked, the car can still consume around 0.5A (500mA).
5. After twenty minutes the car should fully go into sleep and should consume around 0.05A (50mA). Note that clamp meter is not very precise when measuring very small current, therefore, anything less than 100mA is probably fine.
W220 with trunk latch in closed position.
W220 current reading before going to sleep mode.
W220 current reading in sleep mode.If the battery draw does not drop after half an hour, you may try to remove fuse after fuse until the draw drops. Then using fuse charts locate faulty device. Be warned this technique can require a lot of resetting ECUs afterwards.
A common source for parasitic drain is the navigation device which might not go into sleep if the DVD has got stuck or the electronics has failed.
See the DIY guides below for more detailed parasitic drain current tests:
DIY High Current Sensor - Quiescent Current or Parasitic Discharge Tests Summary: Thorough quiescent current draw can be performed by making a current sensor by manufacturing a very low resistance resistor out of a piece of coat hanger and inserting it into the main battery lead. Then a normal Digital Volt Meter (DVM) can be used to measure the voltage drop across the resistance.
only charge it directly connected to battery terminals in trunk , or better yet remove the cars battery cables and charge it while not attached to the cars electrical system
only charge it directly connected to battery terminals in trunk , or better yet remove the cars battery cables and charge it while not attached to the cars electrical system
one wrong move can destroy your electrical system
Thank you so much for the information and advise.
I too was wondering if the information given is right. The web page I found the post seemed authentic but yet I wasn’t 100% sure. Here is the website link from where I cut-pasted the info.
BenzNinja YOU ARE SIMPLY BRILLIANT.... HATS OFF. Never knew such a mini fuse breakout extension even existed.
One question: For trickle charging the battery of a W220 when not being used regularly, a member advised that the battery must be charged by directly connecting it in the trunk or preferably disconnecting it. However, I have read that once you disconnect the battery to keep it trickle charged, the whole system has to reset in a particular way. Disconnecting the battery each time for trickle charging can be quite a bother.
What would be your recommendation on trickle charging a W220 battery (that is in the trunk) where the car is not in regular use?
First - there is a difference between a "trickle charger" and a "battery maintainer".
A trickle charger is older technology that continually applies a small charging current. The problem is that over time, this can over-charge the battery, resulting in damage.
A battery maintainer is newer technology that continually monitors the state of battery charge, and modifies the charge applied to keep the battery correctly charged. A good-quality battery maintainer can be left attached to the battery indefinitely, and will not over-charge or damage the battery. Newer, more expensive model even include battery conditioning modes that can help prevent or even reverse sulfation.
Most battery maintainers include connection options, such as ring terminals, to enable permanent connection to the battery terminals. There is usually a polarized disconnect in the cable, so that the maintainer can be left plugged into the wall, and the car-mounted hard connection simply unplugged.
Yes, disconnecting the battery can create problems, and requires several resets of various systems on the car. While you should not attach a very high-voltage/high-amperage charger to an installed battery, there is no reason at all to disconnect the battery when a battery maintainer is attached. With some knowledge and care, you can tap into one of the "30 bus" (always hot battery circuits) anywhere on the car. This is commonly done so that the hard-connection to the battery is done under the hood, and the maintainer cable run to an easily-accessable location at the grill or at a bumper opening, so that you can simply pull the mid-cable plug and drive away. Of course, many folks have discovered that it is very easy for the driver (either you or someone near and usually dear to you) to forget to unplug, and to pull the maintainer out of the garage and away...
First - there is a difference between a "trickle charger" and a "battery maintainer".
A trickle charger is older technology that continually applies a small charging current. The problem is that over time, this can over-charge the battery, resulting in damage.
A battery maintainer is newer technology that continually monitors the state of battery charge, and modifies the charge applied to keep the battery correctly charged. A good-quality battery maintainer can be left attached to the battery indefinitely, and will not over-charge or damage the battery. Newer, more expensive model even include battery conditioning modes that can help prevent or even reverse sulfation.
Most battery maintainers include connection options, such as ring terminals, to enable permanent connection to the battery terminals. There is usually a polarized disconnect in the cable, so that the maintainer can be left plugged into the wall, and the car-mounted hard connection simply unplugged.
Yes, disconnecting the battery can create problems, and requires several resets of various systems on the car. While you should not attach a very high-voltage/high-amperage charger to an installed battery, there is no reason at all to disconnect the battery when a battery maintainer is attached. With some knowledge and care, you can tap into one of the "30 bus" (always hot battery circuits) anywhere on the car. This is commonly done so that the hard-connection to the battery is done under the hood, and the maintainer cable run to an easily-accessable location at the grill or at a bumper opening, so that you can simply pull the mid-cable plug and drive away. Of course, many folks have discovered that it is very easy for the driver (either you or someone near and usually dear to you) to forget to unplug, and to pull the maintainer out of the garage and away...
Hello Wally,
Thank you so so much for the insight and taking the time to explain everything so clearly. TRULY AND EXTREMELY GRATEFUL.
I believe I have a battery maintainer (Ctek Multi US 7002 charger). I also have a 2007 S550 W221. This car has two batteries. One starter battery in the engine compartment and the other in the trunk. While maintaining the starter battery, I directly connect the charger to it, for the rear aux battery, they have a fuse box (under a black plastic cover) right next to the starter battery in the engine compartment. When you remove this fuse box cover, you can connect the positive of the charge to this long copper stem and the negative to the starter battery or the ground of the starter battery. This way one doesn’t have to disconnect any battery while maintaining the S550 battery. It is the reason I was wondering, whether any such thing can be done for the W220 cars (without disconnecting the battery as that is quite a task). A write up of (maintenance) charging a W220 battery from the engine compartment stated connecting the positive to f33,40 Amp fuse (apparently this is live!!) and the negative to any ground. I saw in Amazon there was this extension which I thought could be put in the f33,40 amp fuse location. May I request if you could give me an opinion if using this would be okay for maintenance charging the W220 battery? Here is the picture of fuse with an extension where the connection can be made.
P.S. I am the only one who drives the cars, hence I shall be careful not to drive away with the charger being plugged in.....
Last edited by Ramero Jorje; 02-03-2021 at 12:42 PM.
I decided to give the charging on the W220 a try. I removed the f33,40 amp blower fuse, put the fuse connector kit (picture posted earlier and obtained through Amazon) in place of that blower fuse and then connected the positive (red cable) from the maintenance charger to it, and the negative (black cable) to a bolt on the body (between the strut and washer fluid tank). It worked....!!! I circled the clamps. I have also posted a picture of the maintenance charger I am using.
Thank you for your help and advise.
Last edited by Ramero Jorje; 02-07-2021 at 12:37 AM.
I guess one could directly charge from the trunk as well but you had indicated it to be risky to charge without disconnecting the battery. Secondly, once the battery is disconnected for charging, then a reset of systems had to be done, which I considered a bit tedious.
I found this way to be easier rather than opening the battery cover, then disconnecting the battery, and then charging it.
This way I just had to take off the f33, 40 blower fuse, connect the red positive cable to right side of the connector, and the other to ground, and it seemed to work.
I guess one could directly charge from the trunk as well but you had indicated it to be risky to charge without disconnecting the battery. Secondly, once the battery is disconnected for charging, then a reset of systems had to be done, which I considered a bit tedious.
I found this way to be easier rather than opening the battery cover, then disconnecting the battery, and then charging it.
This way I just had to take off the f33, 40 blower fuse, connect the red positive cable to right side of the connector, and the other to ground, and it seemed to work.
You completely misread Tusabes post. What YOU did is risky - backfeeding voltage into the electrical system. You could fry all sorts of things.
The best way, the only way, to charge the battery is directly on the posts of the battery itself. You can disconnect it from the car for an added measure of safety, but you need to charge the battery directly, not via the fan, or other circuit.
Applying 12 volts to other parts of the electrical system is an emergency procedure to get you into the car if the battery is dead and the trunk lock is broken, and you have no alternative. Don't do it this way again. Seriously. Connect your C-Tek charger directly to the terminal of the battery itself in the trunk.
Oh GOSH.... I guess I got lucky that I did not screw up my systems in charging it the way I did. Actually a member (Wally) mentioned going through the “30 bus” and I found that too complicated without having a clear idea on how to go about charging the battery. The instructions seemed pretty clear on this website (that I had also cut-pasted above https://w220.ee/Battery) but I guess the website may not be genuine.
Secondly, the other reason why I thought the battery may not need to be accessed directly is because in the S550 W221, a similar size, Aux battery is in the trunk. For maintenance charging this, they have provided a point in the engine in a fuse box right next to the starting battery (I will attach a picture). The positive is connected to the long copper stem that is visible, and the negative to the starter battery. Hence, I thought that the W220 battery can also be charged from the engine compartment.
However, I would consider a member’s advise far more accurate than what websites state. THANK YOU SO MUCH.
Last edited by Ramero Jorje; 02-08-2021 at 12:28 PM.
The w221 dual battery system is totally different from the w220
yes it’s “possible “ to charge your car from the engine compartment , but it is highly dangerous and that’s only in an emergency where you can’t open the trunk like a broken trunk latch .
once you can open the trunk , charge directly at the battery posts .
12-28-2020, 02:20 PM
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