My Nissan Cabstar does not start

My Nissan Cabstar does not start even though I have put the new battery, because it has the failure as if I had no battery, but once started (tweezers or pushing) after a while it does not fail again. although sometimes it seems that it does not start with the joy it should.

A test that you can turn off the vehicle measure with voltimeter the battery Example: 12.86 and in 1 hour without having started the battery again. If you see that at a lot of example: 12,22 is why you have a consumer example: when you close the trunk the light is still on and the battery spends.

Another issue would be that the starter has spent brobillas, it does not do it to beam and starts without force

Thank you, I don't know how the forum works, but I prefer to give you the graduates twice than not to do it.
Salu2