I have a 1997 C230 with original battery. Lately the car wont start and when I check the battery its dead. I charge the battery and everything is fine for 3-4 weeks, then it starts all over again. The alternator and battery have been checked and both put out the necessary specifications. I have checked for the obvious drains, inside lights , glove box, trunk everything is working. My mechanic said we should just replace the battery because of age.
Any ideas??

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5 Kids
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1 Wife