I bought a brand new Motomaster Jump Starter and Power Pack, the 1200 amp one. I plugged it in, it's fully charged. My battery in my 2000 Jeep is totally dead. Haven't driven in for 3-4 days. This is the 4th time this has happened. After the 3rd time I bought the jump starter. I plugged the cables adapter into the booster, hooked the cables to my battery, and not a sound when I turn the key. Do I need a new battery...and what is causing it to die ?

Cars & Trucks - Jeep