I have a reecharge, which I blew out by descending like a loon without taking the current into the battery. Kim repaired it for me and it is now working again. Unlike feline, I have not the skillz to molish myself a switch.
It seems to me that everyone who has one, also has dyno lights and it is a major failing in the design not to have an in-line switch. It makes absolute sense to have a 4 way switch: lights/ battery/ both/ neither.
I don't think there's a problem with the device, if you use it as instructed. User error, here, too. It's always going to be difficult to make something that copes with the massively variably output, and I'm not sure that the method they've designed is ideal. Kim has a more technical opinion on this, though.