Anyone else got internal blinds in their bi-fold doors?

Aibu to be fed-up of mine? The individual battery units that stick on the glass all run out of charge at different times. They're very noisy too. Now it's getting sunnier I need to use mine again & it seems the battery units have lost their capacity to accept charge as I haven't tried to recharge them all winter. The very best I can achieve seems to be a painfully slow & laborious crawl up or down. I undid the screws on one controller to see if it's a battery I can replace but sadly it isn't. It's some weird L-shaped thing that's wired in. Has anyone else had experience of these?