I’ve used a granny charger exclusively since December and it’s worked fine. If we do a really big travel day then it might take 2 days to get back to charge target but it can put enough in overnight to more than handle our average days.
There are some safety downsides to the granny charger in that they may stress your house wiring and expose pre-existing weaknesses because they draw a lot of power for a long period, and there are also scenarios where they may not be earthed effectively which are I only relevant in fairly obscure circumstances but are real.
There are some safety downsides to the granny charger in that they may stress your house wiring and expose pre-existing weaknesses because they draw a lot of power for a long period, and there are also scenarios where they may not be earthed effectively which are I only relevant in fairly obscure circumstances but are real.