Gary Warner wrote:

Is there any easy & safe way to modify the gauge to change it's range?


Looking at their web page, the ammeters are internally shunted so
without tearing the gauge apart to remove the shunt and installing an
external shunt and then dividing the reading there doesn't seem to be
much you can do.

Do you really care that much about the charge rate or system load? They
make a matching voltmeter that will provide useful information about the
status of your system.

Rick