Power Reserve Complications

The power reserve complication displays the amount of energy that the watch has in its mainspring and for how long the movement will continue to run without winding. The power reserve complication is special and unique to mechanical watches.

On a full winding, automatic watches can run for 36 to 42 hours before another winding is required. Some brands of automatics deliver a reserve of up to ten days per winding. Likewise, the manual wound mechanical also features awesome power reserves.  You can expect manual timepieces to run for between 48 hours and up to an incredible 15 days per winding!

Watchmakers showcase their creativity and ingenuity when placing indicators for power reserve display. Therefore the commonplace dia isn’t always where you will find the power reserve indicator. The lack of a power indicator on the dial, however, doesn’t mean there is no power reserve available. Watches may have, depending on design, visible power reserve on the case back.

Types of Power Reserve Indicators in Watches

• Aperture

On the dial, an opening or window features a rotating wheel, via which the power reserve is indicated. Colors on the rotating wheel correlate with the amount of power giving you an idea of how much power the mainspring has remaining. The window is similar appearance to a retrograde.

• Linear

The linear power reserve complication displays the amount of power left in scale format. Watch designers use horizontal markings and a miniature hand that moves along these markings to indicate the respective mainspring power.

• Pie

The pie power reserve complication has a band and hand that moves across it. These show the wearer the mainspring power reserve in terms of hours or days. The amount of residual energy in the mainspring determines the movement of the hand.

• +/-

This power reserve complication uses the + and – signs as a means of reserve power indication. To give the wearer an exact idea of how much reserve power is left, the signs are differentiated. Furthermore, the position of the miniature hand indicates the actual power reserve in the mainspring.

More Information

You may at one time ask yourself, what’s the logic in having a power reserve complication in a self-winding watch?

A key aspect to maintaining accuracy is mechanical watches is having a daily full winding routine. The handiness of a power reserve indicator can’t be downplayed. This is more the case for automatic watches which give no resistance when the crown is wound. Regardless of the improbability of overwinding today’s modern timepieces, having a power reserve indicator is a definite plus.

Furthermore, our forgetful nature doesn’t help much. Picture yourself having gone through the day without noticing how inaccurate your watch has become. A simple case of a half-empty mainspring can cause you many unwarranted inconveniences. Therefore, I am much in favor of having a power reserve complication on my watch anytime.