We have a 2006 Dodge Grand Caravan. We bought a new battery and the van ran fine for a out 4 days. Then I went out to start the car and it was completely dead at first I figured someone must have left a light on or something. My husband got a jump box and as soon as the cables connect the lights go on in the car and it starts right away but when you take the cables off to drive it all the dash lights flickers and the radio goes in and out I drove it 2 mins up the road to the gas station turned it off and couldn't start it again so I jumped it again with the box and it started right up and has no problem driving. I don't get what a going on help!
It sounds like your alternator isn't charging the battery correctly. With the engine running, check the charge. It should be at 13.5-14.2vdc when running properly. If the voltage is lower than that, and/or the voltage is continually dropping, the alternator isn't charging. Take it to a local parts store and have it tested.