Battery is 11 months old, but can't start my Trooper. Jumped it, no start. The lights work fine. I drove it to work. Parked, then was told I needed to move it. Went back out to move it (maybe 5 minutes later) and it wouldn't turn over. Is this a typical battery problem or the starter?

You need a good battery. It should read 12.6v while not running and 13.5v + while running. Sounds like a bad cell. Not curable.

take cables off and clean then put back on

CHeck for loose/bad connection at battery and starter.

Hi,
The Alternator is JUNK, sorry.
Regards,DT

B sure to check the wire oink to the starter for corrosion and check the ground under the hood also your problem is one of those okay thanx Chris

replace the alternator,this is the problem,please rate thank you.

Replace the battery

The ignition relay is faulty.
Look into that.
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Thanks!!

check to make sure the alternator is charging the battery.crank engine while idling the alternator out put should be 13.5 volts to 14.5 volts. if not alternator is not charging the battery.if alternator is charging battery.the battery is weak.if its over 5 years old its more likely battery.if battery not old checks out good .replace battery cables..

Alternator should have better than 13.5v output with all accessories on including headlamps.Check with volt meter right at battery terminals (running) If not it's not working properly. Doubtful from what you have said that starter is bad. Also check that terminal connections are clean and tight on battery.