new battery but after long trips in car battery shuts off

If battery it truly dead the vehicle will not restart. Is battery light coming on? Or volt gauge dropping real low? Is either of these two why you thinking your battery is dead? I would check all battery connections. Loose/dirty connections might cause this kind of issue. Also check alternator belt tension and alternator output voltage. A loose belt and or alternator going bad can cause a battery light or volt gauge to either come on or show low battery charge. Also check alternator connections

to answer your question the battery light comes on when I reach a stop light. but it turns off once I am able to restart the car. Thanks for your other suggestions

Ok battery light. probably loose/dirty battery connections. I would also check alternator output voltage.

dandy and taraneh, when the engine dies (and key is still on) the battery light will come on regardless, the engine is not running, it's just like when you first start the car, the warning lights will all come on and when engine is running will go off. Taraneh, do you have the CEL on when driving? If so, you need an OBD scan. All due respect dandy, there may be something else going on besides battery when a car simply dies after driving for a while then when slowing/stopping

I agree. I took it that the battery was just showing dead(battery light on) but vehicle was still running. But if vehicle is actually going dead then you correct and there is another issue going on.

thanks guys! If CEL means check engine light.. then no it is not on when driving..and yes dandyoun my vehicle does completely go dead when this occurs. I am able to drive my car now.. but only bc I'm driving short distances (short meaning under 3 miles).

Ok so vehicle is going dead. Sorry mis understood that part. This could be several different things.. Dirty/faulty idle air control valve. Dirty throttle plate. Or dirty egr valve. I might would look there first. Highway driving egr stays open for long periods of time. When you start slowing it should close. If it's not closing as quickly as it should your vehicle will go dead. Once it completely closes vehicle starts right back up. Might just need a good cleaning.

Oh and sorry didn't get back to you quicker. I been out of town.

the problem can be solved by JLR SDD here is the solution http://www.obd2knowledge.com/how-to-diagnose-landrover-new-battery- run-out-with-jlr-mangoose-sdd/