DAYS TO SPARE

Days to Spare THE WORLD OF LONG POWER RESERVES

Power reserve is one of those things that isn’t always talked about or praised as much as it should be in the watchmaking world. We all love a good complication, but the technical capability required to deliver a long power reserve efficiently and accurately is a skill worthy of significant praise. To do so at the sacrifice of accuracy is easy, as this can be accomplished by just slapping in a big ‘ol mainspring and hoping for the best. The longer the power reserve, the more one needs to rely on innovation in materials and other elements to maintain accuracy.

Shy of getting into things like the Hublot MP-05 and its 50-day power reserve, when looking at more conventional pieces, anything over the four-day mark is considered lengthy in comparison to industry convention. Much as some ‘standard’ in-house calibers have pushed their power reserves up to 70 hours (just shy of three days), the real industry standard power reserves run around the 40ish hour mark. In the last five years or so, more brands have been pushing these boundaries, and as you’ll see below, the range of mechanical power reserve quickly escalates into the range of several days.

DE BETHUNE DB28 Now available in a wide array of configurations, the beauty of the DB28 lies in more than its clever case design and fantastic finishing. The classic DB28 models (of which there are several variants out there now) has boasted an over five-day power reserve from day one, which isn’t as long as some of its competitors in this list, but still impressive given the slender proportions of its casing. The 42.6mm diameter titanium cases are only 9.3mm thick---not enough to be dubbed an ultra-thin by any stretch, but still quite compact for something as detailed and complex as a De Bethune.

Watch DB28 Reviews Now

PANERAI LUMINOR 1950 10-DAY DESIGN MIAMI LIMITED EDITION (PAM 986) Launched in 2018 as a limited edition extension of an earlier reference, this sun-brushed blue Luminor is one of a 250-piece series launched during Design Miami---an event that runs each year adjacent Art Basel. Using the classic Luminor case with lock-down crown, the combination of a sun-brushed blue dial and faux vintage luminous hands and indices is a nice deviation from more conventional models. Powered by an older in-house automatic caliber, the P.2003 boasts a 10-day power reserve made possible by a trio of mainspring barrels. Its power reserve indication is an interesting one, as it displays reserve over a linear scale.

De Bethune DB28 GSB

Panerai caliber P.2003 delivers 10 days of power to PAM986

“BY CREATING A PIECE WITH A LONGER RESERVE, HE COULD CREATE A STABILIZED WINDOW OF OPERATION WITH OPTIMAL EFFICIENCY.”

F.P. JOURNE OCTA AUTOMATIQUE RÉSERVE As a man obsessed with chronometric accuracy, there’s little surprise that F.P. Journe has thrown his hat in the ring in this category repeatedly. The interesting part of the equation here is that the Octa Automatique Réserve carries a stated power reserve of 120 hours (five days), however it is plenty capable of running a fair bit longer. For Journe, the idea was simple. By creating a piece with a longer reserve, he could create a stabilized window of operation with optimal efficiency. Outside the 120h range, the piece would certainly keep running, but within it you can expect stability that is at least equal or greater to that of COSC-certified calibers.

A. LANGE & SÖHNE LANGE 31 31. That’s right, 31. Not hours, but days, which means a staggering 744 hours of reserve out of an otherwise conventionally designed wristwatch from the Glashütte powerhouse. To make this magic happen, we’re dealing with quite the substantial piece of metal, measuring 45mm in diameter and 15.9mm thick. Using only two VERY long mainsprings contained in a centrally positioned barrel, the Lange 31 is manually wound rather than self-winding like the two previous models discussed. This is primarily on account of the amount of effort that would be required to spool up these beefy mainsprings using a self-winding rotor.

Watch the Review Now F.P. Journe Octa Automatique Réserve; pictured in platinum and rose gold (below)

A. Lange & Söhne Lange 31

Caliber 9R01 powers the Grand Seiko Spring Drive 8-Day; SBGD201

Hublot Big Bang MECA-10

IWC Portugieser Annual Calendar Limited Edition

HUBLOT BIG BANG MECA-10 Polarizing as they are, I’ve long had a soft spot for the big bad Hublot MECA-10. Movement architecture modeled after the children’s industrial erector set known as Meccano, there’s something to the futurist/industrial skeletonized caliber with a 10-day power reserve that has long been calling my name. The simple time-only watch has a pair of unique ways to indicate the state of its reserve: a digital disc that shows the number of days remaining, and a red segment on its mainspring barrel that comes into view as the watch creeps towards the end of its running potential.

Watch the Review Now IWC PORTUGIESER ANNUAL CALENDAR LIMITED EDITION While most of our selections are light on the complication front and focus more on extended run time, the IWC Portugieser Annual Calendar delivers the best of both worlds. 44.2mm across and sporting a slick forest green dial, this in-house powered beast packages an easy-to-read annual calendar function with a 7-day power reserve, saving its owner the hassle of having to adjust the calendar function should the watch stay dormant for a few extra days than planned. While the intent of the Portugieser line is to play to a dressier crowd, this piece dances the line between dressy and casual, while displaying faint hints of the brand’s pilot-centric heritage. GRAND SEIKO SPRING DRIVE 8-DAY SBGD201 Those more familiar with Grand Seiko are likely not surprised to see this reference surface in this list. Taking advantage of both mechanical and quartz technologies in especially interesting fashion, and mating calibers with cases, dials, and hands with finishing levels that trump pretty much anything in the price point makes a Grand Seiko a no-brainer recommendation. When talking about power reserves, the SBGD201 packs a mechanically driven 8-day reserve that powers its way through a quartz oscillator, so there’s no cheating going on as far as where the power comes from. The 2017 release was the first from the Grand Seiko Micro Studio, using the first of its new 9R series calibers with extended power reserves.