Depends on what year EVSE it is. Newer ones can only be upgraded to 16a, of course, if you only have a 3.6kw Leaf charger that would be OK, otherwise, if you have the 6.6kw charger, you'll only be charging ~1/2 the speed you could. Nothing inherently wrong with using a EVSEupgrade permanently though, if you're OK with possible slower charging than max.