I wouldnt go anywhere or do anything nor park the car in the garage until you figure this out. None of us here like to hear that power disconnect is being associated with the position of the HOOD… This strongly suggests that you either have loose batt terminals…which may have been indeed tightened to their limit yet are still unable to produce clamping force on either terminal…a very common occurrence. OR…the new battery is now taller than the old one and there is some sort of unwanted contact of the hood to battery…this is NOT GOOD and must be diagnosed immediately.
Sounds like your hood is applying pressure to either connection and allowing it to make contact (most likely the ground side since no fires have erupted as of yet)…and when the hood is released…this pressure is also released and no battery contact is present. This is bad for many reasons…Worst case is hood contact with the positive side and grounding out the battery… Fire is the next act in this scenario.
If you find that your positive clamp is unable to grasp the terminal…or the negative as well…they sell battery post adapters made of lead that basically enlarge the diameter of either post of the battery…which allows the battery clamp to grasp hold properly. They cost .99 for a pair ? Not ideal but they work when needed. Replacement clamps are hard to install correctly and it is a dis service to install those .99 c batt clamps in place of the factory ones currently installed.
The batt posts are actually different diameters…the pos batt post is fatter than the negative…just apply the post adapter to whichever one that needs it. You may find that you can only utilize half of the post adapter bec the whole thing is too big…adjust as needed, they can easily be cut and sized accordingly.
Please figure this out asap. Shouldnt be too hard to troubleshoot…but by all means…do this NOW.