Found these old rechargeable C batteries. They look like they are from the early 90s. : r/batteries
Duracell - Alkaline C batteries, pk. of 4 | Rossy
C Cell USB Rechargeable Batteries | Pale Blue – PaBlueEarth
Energizer NH35BP-2 2-pk C NiMH Rechargeable Batteries, Pre-Charged, Long Lasting | Canadian Tire
C Alkaline & Rechargeable Batteries | Energizer
Lithium C Batteries, 1.5V / 3000mAh, Micro USB Rechargeable C Cell, Durable & Lasting Performance - ECO-Friendly & Recyclable - No Memory Effect - 2 Pack : Amazon.ca: Health & Personal Care
Buy Energizer Max C Batteries at Well.ca | Free Shipping $49+ in Canada