Pawan G's Comments

The link heart of the SolarBeat is a new Cartier quartz movement, powered link by light, which Cartier says should run link for at least 16 years before its rechargeable battery needs to be replaced. The only parts of the dial which let light through to the photovoltaic cell underneath, are the numerals. This is a neat trick – it probably doesn't hurt that the watch only has to update the positions of the hour and minute hands, so energy costs for actually moving something are pretty low.