which when its starts up the alt should be charging the battery Right?

 

charge the battery fully. Start truck, check voltages. Report back.

How long does the truck have to sit before the battery dies?

 

Right. Does gauge show charging or discharging? If you leave it battery cables on for a bit does it keep running. If i was going to guess I'd say battery is shot and wont take a charge. It is hard on alternators using them as battery chargers. Did you get 12 volts across battery terminals with truck shut off?

 

yes the battery is doing its part i charge the battery full charge but it wont keep a charge

 

Take it back. If it's new there should be a warranty. I've had batteries that passed the load test, but every morning it would dead. Autozone gave me a new one and it worked fine. And I have got bad ones from Sears that were shot in a month. It happens.

 

Question becomes, was it doing this with the old battery as well?