Dodge Charger Battery Jump

Battery Save Mode Warning Came On Driving To Work Left To Drive Home After Work And My Car Stereo Shut Off And Gauges And Warning Lights...

I Am Trying To Use The Dodge To Give A Jump Start To A Ford Expoditon. And When I Hook The Jumper Cables To The Battary In The Trunk It Dose...

The Battery Takes A Jump, But It Discharges When The Engine Is Running And The Lights Are Used. I Think It's The Alternator, Or Should I Be...