I'm preparing to open a chain of mobile device and accessory stores. My biggest fear is that I'll lose money on the quality of cheap parts. I've handled a bunch of cheap knockoff batteries—they'll just die in three months, and customers will come back and complain.

I want to immediately order a large wholesale batch of decent batteries directly from a manufacturer that strictly controls all assembly stages.

Which factories are worth dealing with right now to avoid embarrassment in front of customers and get decent wholesale terms?