Eco-Drive- Extracting The Power From Light

The Citizen Eco-Drive Watches Insight

By Sam Ammouri


sam ammouri

The Citizen Eco-Drive platform that made the Eco-Drive concept possible was the Eco-Drive caliber 7878 movement. This unique brainstorming by citizen was the first light powered movement where the solar cells could be mounted under the dial.


Past light powered watches from Citizen and other manufacturers had the solar cells mounted directly on the dial. This new innovation was enabled by marked improvements in thin film amorphous silicon solar cells, which, by the early 1990s had become significantly practical. 

The new concept thrived By locating a sufficiently translucent dial material over the now more efficient solar cells, enough light could pass through the dial face to power the movement. Though the Eco-Drive caliber 7878 movement solar cells remained slightly visible through the dial, the design of the light-powered watch was no longer constrained by visible solar cells.

In order to restore electrical energy,  the first Eco-Drive movements employed titanium lithium-ion rechargeable or secondary batteries. This battery type became available in the early 1990s, enabling an Eco-Drive 7878 movement to run for almost 6 months on secondary power before requiring recharging via light exposure- a very noticeable  improvement in energy storage over previous light-powered watches.

If you find this helpful please share and spread the good news, you can also leave a comment below, and if you need any further assistance please don’t hesitate to contact me either by the comment box below or using this contact form here.

sam ammouri

Sincerely Yours

Sam Ammouri

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.