Mechanism and Recharging

A solar watch is not recharged even though it was exposed to light. Is it broken?

Sufficient strength of light and amount of time are necessary in order to recharge sufficiently. In case the strength of light and amount of time are not enough, there is a possibility of insufficient recharging.

A Solar Watch is a watch which moves by converting light energy into electronic energy.

Light energy received by a solar cell (solar cell unit under the dial) is converted into electronic energy. The energy is stored in the rechargeable battery and is used to move the watch.

Unlike a disposable battery such as dry battery and button battery, a rechargeable battery is an eco-friendly battery. It can be used for a long period of time by recharging and discharging the energy repeatedly.

Environment Suited for Recharging

In order to recharge a solar watch, it is necessary to expose it to light.

Since room light is weaker compared to sunlight, it takes a longer time to recharge the watch. Therefore, when recharging, please place the watch by a window and expose it to sunlight with the dial facing the sun.

When recharging the watch, make sure that the watch is not heated to a high temperature.

Guideline for Light Source (lux)


Under direct sunlight on a summer day About 100,000 lx
Cloudy day
About 10,000 lx

Room Light

5cm from 30W-fluorescent lamp
About 10,000 lx
20cm from 30W-fluorescent lamp
About 3,000 lx
General office
About 700 lx

"Lx (lux)" is a unit of illuminance and luminous emittance used for measuring the intensity of light.
One lux is equal to one lumen (amount of light) per square meter.

For details on necessary recharging time for each caliber, please refer to the instruction booklet.

Environment not Suited for Recharging
A solar watch cannot be recharged in the dark. Under the following situations, the energy is likely to run out, resulting in stoppage of the watch.

  1. The watch is concealed under a sleeve.
  2. The watch is used or stored under conditions where it cannot be exposed to light for a long time.

The watch cannot recharge enough energy from wearing it on the wrist. Make sure to place it by a window and expose it to sunlight when not wearing it.

How to Care

The capacity or recharging efficiency of a rechargeable battery may gradually deteriorate for various reasons, such as long-term use or usage conditions. Worn or contaminated mechanical parts or degraded oils may also shorten recharging cycles.

We recommend you have it serviced (overhauled) every 3 or 4 years in order to ensure it functions perfectly and will be able to be used for a long time.

An overhaul is like a health checkup for a watch. It is important to check inside the watch for retention of oil lubrication, looseness of screws, rust from dirt and sweat, and deterioration inside the case. By having an overhaul, dirt and sweat on an unseen part will be cleaned off, preventing a malfunction. In addition, any worn out parts and gaskets will be replaced to ensure that functions and water resistance works perfectly like a new watch.

If you need an overhaul, please contact the nearest Customer Service Center.