Over the past ten years, the power reserve of mechanical watches (PowerReserve) has gradually increased, although this trend is slow but firm. The long power reserve is simple and convenient, once considered a feature, and it is becoming more common today.
For a long time, mechanical watches usually had a two-day power reserve. At that time, most people only had one watch and wore it every day, so the short power reserve was not a problem. At the time, the watch and the movement were small in size, and there was not enough room for a large-capacity spring, so it was difficult to achieve a long power reserve.
Grand Seiko 9S65 caliber has a power reserve of up to 72 hours
For most of the 20th century, watches with long power reserves were rare. LeCoultreCalibre124 is one of the few examples. The movement has an eight-day power reserve and was produced in the 1930s and 1940s. It is supplied in small quantities to brands such as Patek Philippe and Cartier. On May 14, 2014, a Patek Philippe with Calibre124 movement sold 93,750 Swiss francs at Sotheby’s. In 2005 and 2009, two Cartier tank watches with Calibre124 movement were sold at Sotheby’s and Christie’s for 84,000 Swiss francs and 99,000 Swiss francs.
In the early 2000s, the long power reserve suddenly became popular. Several manufacturers, including Patek Philippe, IWC, Parmigiani, Jaeger-LeCoultre and Chopard, launched movements with a power reserve of one week or more. Most of these movements are manually wound, and Calibre 5000 movement of IWC is a special case. At that time, the watch equipped with a long power reserve movement was very special, and the watchmaker described its advantages in the press release. For example, in 2000, Patek Philippe launched the Ref. 51000 ‘Devil’s Fish’ watch to commemorate the new millennium, which is equipped with a newly developed Calibre 28-20 / 220 movement with a power reserve of up to ten days.
Interestingly, the gradual increase in power reserve coincides with the popularity of “big” watches (the standard diameter of men’s watches increased from about 35 mm to 40 mm and above). The larger case provides more space for the movement and fits longer springs. There are also watches with power reserves that are beyond practical use, such as the Lange (A. Lange & Söhne) with a 31-day power reserve, the Rebellion T-1000 with a 41-day power reserve, and 51-day power. Reserve Hublot Ferrari watches.
A month or longer power reserve is a special case, but a long power reserve is very practical and will become more common. The standard power reserve of modern mechanical watches is still 48 hours. The next three days or longer, a power reserve sufficient to spend the weekend will become the norm. One reason is convenience. Today, watches have evolved from practical instruments to personal accessories or luxury goods, and it is common to have multiple watches. Alternating wear requires repeating the winding and adjustment operations, except for automatic watches placed on the winder.
Once a complex timepiece with a calendar function is stopped, it is particularly inconvenient to recalibrate, especially those calendar watches with multiple buttons. The new-generation GrandSeiko movement all has a 72-hour power reserve and is specially designed and developed. The watch owner can remove the watch on Friday and not have to wear it all weekend. When work started on Monday, the watch was still running and no adjustments were required. The three-day power reserve is extremely convenient and is likely to become the new standard.
Thanks to technological advances, it is possible to achieve a three-day power reserve even for relatively affordable watches. Advances in metallurgical technology have made springs thinner and more flexible, so that barrels of the same specifications can store more energy. This is important because the increase in watch case size has stagnated, and the average diameter of men’s watches is about 39 mm to 42 mm.
Without changing the size or architecture, a number of well-known modern movements have achieved power reserve upgrades. The new-generation Calibre L951.6 movement in the Lange Datograph watch has a power reserve of 60 hours, which is higher than the original 36 hours. The same is true of the Hamilton H-21 movement, which is an improvement on the Valjoux 7750. The Valjoux 7750 movement can operate for 42 to 44 hours, while the H-21’s power reserve is 60 hours, a 36% increase.
The popularity of silicon parts (especially in escapements) also helps to improve the power reserve because it means a reduction in friction losses. For example, silicon components (and other improvements) extend the power reserve of the Patek Philippe Caliber 240QP movement by 50%. The Cartier IDTwo concept watch has a power reserve of 32 days despite its unusual size (42 mm). This watch has several features, including a frictionless escapement, a vacuum case, and the most interesting four small springs made of fiberglass (coated with parylene). Perhaps the only drawback of this progress is that it makes watches with a power reserve of seven or eight days from novelty to ordinary. (Photo / text watch home compiled by Xu Chaoyang)