Battery Issue? Please help!
 

Hi Guys,

I've returned home after quite some time away, and it turns out my 98 SLK 230's battery has failed, according to my parents at least.

I tried removing the battery and recharging it with a Mercedes charger which plugs into the wall. After charging overnight, the charger indicated a full charge.

I put the battery back in, and was able to start the car just fine, but as soon as I started driving it and pressing down on the gas, it started to "sputter."

What I mean by that is, in 2 second intervals, the engine would seem to lose power, not responding to the gas pedal, then suddenly kick back into action before losing power again, causing the car to move forward in a bunch of lurching actions.

(edit) Also, releasing the gas pedal would not cause the car to slow back down to a nominal speed, as normally it would. Instead, the car continued to proceed at its current speed, lurching forward as it went, until I applied the brakes. I had not engaged the cruise control, although I did attempt to disengage it just to make sure, and that had no effect.

During this time, the ABS indicator light as well as the BAS/ASR light came on.

I brought the car back to the curb and parked it. After that, it cannot start anymore. Turning the key brings the power on, and then turning it more to start the car causes a complete power failure - at which point, it can no longer display the time or even use electronics to lock/unlock the doors. After exiting the car and coming back in, I am again able to power the systems on, but again the power fails if I attempt to start the engine.

I'm hoping this is all a battery issue? The unusual behavior while driving causes me to think that there could be other things wrong as well.

If anybody has any clues or suggestions, I'd be very appreciative!

I had a similar experience... SLK is very sensitive to battery change... After charging the battery and reconnecting it you have to leave it for a night... Just to permit the management computer coming back to life... Disconnect the negatif for an hour... Reconnect... Try next morning...

Yes, 230 slks are VERY battery retentive...they don't like giving them up and can create quite a stink when they are changed--- I know---it happened to me a few years ago. The extraction/exchange is now similar in my mind to a transplant operation; it must be done with great care ( oh, for a Ford!). Follow the owner's manual precisely and don't omit a step! Put new battery in the car (be SURE it is good, holding a charge, has water in every cell if it is a refillable type, terminals are clean, etc.). and connect EXACTLY as per manual. Leave it alone awhile to adjust. When you start the engine DON'T drive it for about 10 minutes to allow computer to reset all codes. Also, be aware that battery connections must be tight and not allowed to come loose while engine is running or comuter will fry! ABS/BAS lights will come on unless thye battery is fully charged---they are made to do that. Also, In short, say your prayers, because changing the battery is about the simplest thing on a SLK!