Using phone hotspot for yoto Wi-Fi

I’m not sure if this is the right space to post in. We spend a lot of time in our campervan without Wi-Fi and I use my phone to hotspot the boys yoto’s. However, when I do this, the connection isn’t very reliable and if we’ve been out for the day and come back, I have to reconnect all over again. It doesn’t automatically reconnect like it would on our Wi-Fi when we come home. Am I doing something wrong? Or is there something else I can do to keep a good connection? So I don’t have to keep fiddling around getting them to connect again.

Thanks!