So what does that have to do with DRM? That's what products liability suits are for. You sue the maker of the shoddy battery/charger. DRM can't protect you from that -- what happens when you buy the whole device from the shoddy vendor?

edit: Yes, of course some of the vendors will be gone or judgment proof. So don't buy from disreputable vendors. Which brings us back to the original problem -- if the user is willing to buy from them, they could just as easily be buying an entire laptop or a toaster for their kitchen. So solve it the way you solve those instead of stamping out competition, because you need to solve those anyway.

Or put it another way: If OEMs really wanted to solve this, they would stop overcharging so much for chargers and battery replacements so that people wouldn't have to play the Chinese equipment lottery to avoid paying a 1000% markup.