Won't stay charged!! 71 super beetle trike
 

Help please, we have a 71 super beetle converted into a trike and oh my we have a charging issue. We have changed starter, 3 different batteries, 3 different voltage regulator, a new generator, distributor cap and it will not stay charged. We had mice chew wired and it was shorting out, we then rewired the hole thing....It will not stay charged what can we do????