1988 Toyota Celica Altranator

1988 Toyota Celica 4 cyl Front Wheel Drive Manual alot miles

2 monthes ago I had an altranator ( new ) put in.
Yesterday another had been put in and I had only drove it 8 miles and it had gone out again.
Now, the first time the machanic said that the battery was touching the metal that holds the battery in place thus sending a spark to the altornator and burning it out. Now, last night when I was driving to do chores for a friend, the battery light came on, it had done this again because of it touching the metal. The new altranator is burned up again. Is this true about the battery holder downer thing being made of metal and the battery touching it is why my altornator is burning out? And what can I do myself. (Find rubber to wrap the battery, ha, ha)