Mercedes Benz 190e Battery

Hi, I Just Put A Brand New Interstate Battery In My Benz. Sometimes My Car Doesn't Start. I Think It's The Alternator. When I Try To Start...

L Have Been Having This Problem For 1 Month First The Speed Meter Was Not Working Then A Mechanic Opened The Display Dash Board Later Failed...

Scenario: Battery Seems To Be Discharged When Headlights Are On. Anti-lock Light Comes On, Which To My Understanding Means Less Than 10v...