Car trouble

Flickering gauges are a sign of bad or weak charging system, and the fact even new batteries are dying in this car indicates a problem with the charging system. Even though you replaced the alternator take it in and have it tested, even new/rebuilt units can be defective, it may be a problem with the regulator. You need at least 13.5v to the battery when charging. Be sure to inspect your battery cables and grounds. There are multiple grounds on a car, but you really want to make sure the alternator and neg. batt. cable are well grounded. Last is wouldn't hurt to inspect the serpentine belt as well, make sure it isn't loose. If the tensioner is fading the belt may be slipping on the alternator pulley.

All that seems fine, as soon as you crank car it reads power at alternator then shows no power from alternator???? Is there something else that would make alternator not work even though it is a good altenator

Could it be some other electrical problem?

I've bought brand new alternators that turned out to be bad. They are remanufactured units, if it tests bad, return it and get another one.