When the power reserve is low, a Sundial watch will indicate this by the seconds hand “jumping”, or moving in two-second intervals.
To replenish the power reserve, expose the watch to light. Sunlight will charge it fastest, but strong artificial light of more than 1,000 Lux can also be used. Please see the recharging table below for approximate charge times under various lighting conditions.
If the watch has stopped, it may restart immediately on exposure to light. However the seconds hand will initially move in two-second intervals, indicating that the energy stored in the power cell is not yet sufficient for normal use. If the watch is turned away from the light at this point, it may stop operating.
Keep the watch exposed to the light at least until the second hand resumes normal one-second intervals.
It is not necessary to charge a Sundial watch fully in order to use it. Just one or two minutes of strong sunlight will charge it for a whole day’s use. However, a full charge as per the guidelines on the recharging table will increase the chances that this process will not have to be repeated, as the reserve will then have more time to automatically replenish during day-to-day use.


When charging a Sundial watch, do not place it too close to a fluorescent lamp or other light source as temperatures exceeding 50°C could cause damage to the watch movement.
If a Sundial watch has completely stopped, the date and time will need to be set after charging.


A Sundial watch has a power reserve which allows it to run for six months on a full charge, without further recharging (i.e. if it is stored in the dark for that time).
During normal use, the power reserve is automatically replenished whenever the watch is exposed to light.
Every Sundial watch features a quick start function. If the power cell is fully depleted, quick start allows it to resume operation within a few seconds after exposure to a light more than 1000 Lux (equivalent to a 30W fluorescent lamp at 70cm distance).
When the power cell charge reaches a predetermined voltage, an overcharge prevention function is activated to prevent the power cell from deteriorating.
The following table shows details of how long it takes to charge a Sundial watch from zero, under various lighting conditions.  If your watch has stopped, a full charge is recommended when possible.
sundial watch specification


Since a Sundial watch needs no battery changing or maintenance, it has been designed without a removable caseback. In the unlikely event of a Sundial watch needing repair, we recommend contacting our Service centre.

Solatrex International Ltd., t/a CALCUL
Bay 20 Free Zone West, Shannon, Co. Clare, Ireland.
Tel.: +353 (0)61 472 722


To prevent energy depletion and therefore avoid the need for the above recharging procedure, a Sundial watch should be left it in a brightly lit place on days when it is not being worn. The giftbox supplied with every Sundial watch is designed to be kept and used for storage (without the lid in place). The watch can be angled as needed on the c-clip to give maximum light exposure to the dial.