Battery problems on my C230 kompressor sport
#11
07-16-2019, 08:26 AM
To answer some of your questions, yes the alternator can be part of the problem. So let's get the basics down on the battery, alternator and voltage regulator. The battery is used to start the engine. This is why batteries are rated by cranking amps. Amperage or Amps can be describes as the amount of current flow or in simple terms muscle power. Once the engine is started the battery does not provide an electrical source to any part of the vehicle in order for the vehicle to operate. The alternator is the component that provides electrical source for vehicle (electronic fuel injection [fuel pump], all electricals). The alternator is an AC generator of sort that runs off the crankshaft as such varies with engine speed. The wavelength of AC current is not usable, however a set of diodes in a bridge essentially smooth the AC wavelength into a DC direct current that is usable.
So if the alternator is not working or partially working you can verify this by turning on your headlights with the engine running, then press the accelerator and watch if the headlights dim each time you rev the engine. If this happens, you are most likely running off your battery as you mentioned and the alternator is not powering the electricals.
Since you have 64k miles, the alternator brushes that contact the armature my be worn out or the springs on the brushes are weak. Another problem may be the windings on the coil are fried. These windings are made of thin cooper wire. You can actually teardown the alternator yourself and change the brushes and springs. The diodes are most likely embedded in Alternator case.
Another contributor may be the voltage regulator,VR. The VR does several things: regulates output voltage. Remember the alternator is running off of the crankshaft thru the belts and pulley. Because the engine speed varies with throttle input, the alternator turns accordingly as well. It is the job of the VR to maintain 115 volts for the vehicle's electricals, including the ignition sys, fuel system, lights,.accessories, etc... The VR has a reversed current relay (I think) that supposed to de-energize when the battery voltage is equal or greater than the output of the alternator. Remember after the car is started, the alternator does a trickle charge of the battery through the Reverse current relay. Typically, the reverse current relay is part of the VR (voltage regulator ) and most likely solid state in today's electronics.
Summary:
1. Check the brushes and springs on the alternator. There's probably 3 or 4 bolts to open the alternator... Of course you have to remove the alternator. No timing issues to be concern with when removing the alternator.
2. Replace Voltage Regulator and the Reverse Current Relay, these may be comprised of one unit. I would check with the MB dealer and ask them where it is located.
3. After step 1 and 2, replace the battery.
Remember a simple test right now that you can do in the existing condition. If you can start the car, and turn on the headlights, while pressing down on the accelerator (in park), have someone verify if the headlight get brighter with the acceleration of the throttle.
You can replace the alternator easily enough or if you have your alternator overhauled. Brushes and springs are cheap. A new rotor would be more expensive that is if the coil is fried. Look for a re-manufactured alternator, typically good as new but cheaper.
As far as the VR is concerned ask the MB dealer to.show you where it is located.. I would guess it is under the hood, mounted near the firewall or fuse box.
So if the alternator is not working or partially working you can verify this by turning on your headlights with the engine running, then press the accelerator and watch if the headlights dim each time you rev the engine. If this happens, you are most likely running off your battery as you mentioned and the alternator is not powering the electricals.
Since you have 64k miles, the alternator brushes that contact the armature my be worn out or the springs on the brushes are weak. Another problem may be the windings on the coil are fried. These windings are made of thin cooper wire. You can actually teardown the alternator yourself and change the brushes and springs. The diodes are most likely embedded in Alternator case.
Another contributor may be the voltage regulator,VR. The VR does several things: regulates output voltage. Remember the alternator is running off of the crankshaft thru the belts and pulley. Because the engine speed varies with throttle input, the alternator turns accordingly as well. It is the job of the VR to maintain 115 volts for the vehicle's electricals, including the ignition sys, fuel system, lights,.accessories, etc... The VR has a reversed current relay (I think) that supposed to de-energize when the battery voltage is equal or greater than the output of the alternator. Remember after the car is started, the alternator does a trickle charge of the battery through the Reverse current relay. Typically, the reverse current relay is part of the VR (voltage regulator ) and most likely solid state in today's electronics.
Summary:
1. Check the brushes and springs on the alternator. There's probably 3 or 4 bolts to open the alternator... Of course you have to remove the alternator. No timing issues to be concern with when removing the alternator.
2. Replace Voltage Regulator and the Reverse Current Relay, these may be comprised of one unit. I would check with the MB dealer and ask them where it is located.
3. After step 1 and 2, replace the battery.
Remember a simple test right now that you can do in the existing condition. If you can start the car, and turn on the headlights, while pressing down on the accelerator (in park), have someone verify if the headlight get brighter with the acceleration of the throttle.
You can replace the alternator easily enough or if you have your alternator overhauled. Brushes and springs are cheap. A new rotor would be more expensive that is if the coil is fried. Look for a re-manufactured alternator, typically good as new but cheaper.
As far as the VR is concerned ask the MB dealer to.show you where it is located.. I would guess it is under the hood, mounted near the firewall or fuse box.
Now, here is what I did and this may be helpful to other to diagnose the problem as well.
1) while the car is running( jump start it if you must, but get it running), connect the volt meter to the battery terminals. Check the voltage. It should be about 14.5 volts. Of course make sure you are checking the dc voltage and not ac. If you are reading 14.5 vdc while the car is running then the alternator is probably fine and you just may have bad battery.
2) if the voltage reading you are getting is 13vdc or lower or if it's jumping up and down then you have a problem with the alternator more than likely.
3) now how do you know if the voltage regulator is bad or if it's the alternator? I found that if the car, while it's running, is not making drinking or squeeling noise the alternator is generally still good and the problem is just the voltage regulator and you don't have to replace the whole thing. The mbz c230 kompressor voltage regulator actually part of the alternator. It's attached to is with 2 small bolts and it also has brushes on it.
The way I fixed it is by lifting the car up and from under the car I was able to access the two bolts that were holding vr inside the alternator. I took those out and removed the vr. I took the new be and installed it the same way the old one was. Put the two little bolts back on and that was it. It took me longer to lift the car than to replace it.
Price for the new alternator is between $200 and $600. Voltage regulator is about $20 bucks. I hope this helps.
Remember if the car is not grinding or squeeling it may not be the complete alternator. Alternators have bearings and if those are bad car will make noise. If they are fine it will run just like if it was working perfectly fine.
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