Some of the early solar watches of the 1970s had innovative and unique designs to accommodate the array of photovoltaic solar cells needed to power them. In the 1990s, Citizen started to sell light-powered watches under the Eco-Drive series name. Since their introduction, solar devices have greatly improved their efficiency and thereby their capacity. Watchmakers have developed their technology such that solar-powered watches are now a major part of their range of watches.
Some vintage Solar watches
Typically, sunlight and artificial light are absorbed by a solar panel behind the crystal. The dial is either on a layer above or actually on the solar panel. This solar panel converts the light into electrical energy to power the watch. The watch will usually store energy in a rechargeable cell to power itself during the night or when covered such as a wearer’s clothing. Citizen’s watches use lithium-ion batteries to store sufficient energy to power the watch for several months/years without light exposure, by allowing the watch to enter a power-saving or hibernation mode during which the seconds hand stops until the watch is re-exposed to light. Not all have a power-save mode, yet will still hold a charge for typically six months, as with uncomplicated (date only) analog versions made by Citizen.
Since the release of the early solar powered watches there have been massive improvements in the efficiency and storage capacity of the solar panels on your watches. The storage capacity of today’s solar powered watch is so great that an Eco-Drive watch can run with no further charging from 30 days to 3,175 days (over 8 years) depending on which model you buy.
Another positive of the technological improvements is that solar watches of today don’t have to have the crazy innovative designs that the solar watches of the 70’s and 80’s needed in order to incorporate the solar panels to power the watch. Thankfully the solar powered watch of today doesn’t look like some scary vision of what the 70’s thought the future would look like. They look just as stylish as any other watch you’d find today.
Solar watches dont Not Just Take Power From The Sun
Even though the name solar powered implies that the watches derive all of their power from the sun, this is not the case. You can charge up solar powered watches with artificial light as well as sunlight. This means that your solar powered watch is going to be a lot more reliable than you would imagine as it will charge up whether in sunlight or artificial light.
Even though you’re unlikely to be out of the sun for long enough for your watch to run out of charge, if your watch charges up under artificial light then you know that you’ll always have a lot of charge on your watch.
Constantly Charging
One great positive of solar powered watches is that they are almost always charging, which means that the power reserve is only used when there is no light source. Some Eco-Drive watches have a power reserve of more than 8 years.
Made By The Most Trusted Watch Manufacturers
Solar watches are made by the top watch manufacturers like Eco-Drive by Citizen, G-Shock by Casio and Solar by Seiko. Buying from the best quality brands means that you will receive quality accurate watches which will stand the test of time. It also means that you will receive a full guarantee from the manufacturer, which will give you piece of mind in case anything goes wrong.
Citizen Eco-Drive
The technical platform that made the Eco-Drive concept possible was the Eco-Drive caliber 7878 movement. This movement was the first light-powered movement where the solar cells could be mounted under the dial. Previous light powered watches from Citizen and other manufacturers had the solar cell(s) mounted directly on the dial. This innovation was enabled by improvements in thin film silicon solar cells, which, by the early 1990s had become significantly more efficient. By locating a translucent dial material over the now more efficient solar cells, enough light could pass through the dial face to power the movement. Though the Eco-Drive caliber 7878 movement solar cells remained slightly visible through the dial, the physical styling of the light-powered watch was no longer constrained by visible solar cells.
To store electrical energy the first Eco-Drive movements employed titanium lithium-ion rechargeable or secondary batteries. This battery type became available in the early 1990s, enabling an Eco-Drive 7878 movement to run 180 days on secondary power before requiring recharging via light exposure – a marked improvement in energy storage over previous light-powered watches. The movement also featured an “insufficient recharging” indicator
Since the first solar powered watch was released in the 1970’s, solar technology has improved. Early watches were made in strange styles in order to accommodate the solar panels and weren’t always all that reliable.
The improvements mean that a solar powered watch is just as reliable as a quality quartz watch. So, if you want a quality watch which helps the environment and is incredibly reliable – a solar powered watch might be just what you are looking for.
12 Comments
Johnny McLain
Very interesting and informative (as always).
Bert Perdue
Love my solar Seiko’s ! Thanks Mark !
Bob
I’ll always be a mechanical guy but these are great devices all the same.
Mark Morgan
Great story Thank You Mark
Russ Keller
Also a big fan of the Seiko solar.
Miami Mike
Someone brought me an Eco-Drive watch which wasn’t running and asked if I could fix it. He said it was from an estate and had been in a drawer for a couple of years. I put it out in the sun for two days to charge it and it worked just fine. I told him the reason the watch wasn’t working was because it was afraid of the dark. (I only charged the watch, not him, after all, I do have SOME conscience!)
Manh Pham
This article has shed light on the manufacturing of solar-operated watchmaking industry. Famous watchmakers such as Omega, Citizen, Seiko, Bulova, and others also make solar-operated products. to satisfy their customers’ taste.
A question arises regarding mechanical and solar watches. Which type lasts longer and more economical in term of service charge?
Thank you so much for your blog, which is as interesting as ever!
craig eades
thank good info there was thinking of getting a citizen ecco drive
Wallace Clements
I have had a Seiko solar quartz watch for 4 years now and it is not only the most accurate watch I have ever had but it remains charged up even when I don’t make any special effort at all to expose it to light of any sort, sunlight or artificial light. I just go about my daily business without even thinking about whether it is exposed to light or covered up by my sleeve. I highly recommend Seiko solar quartz watches.
Rick
Love my Citizen and Seiko solar watches. (Purchased a Seiko Coutura recently. ) If you elect for an analog solar with perpetual calendar you can have a practically zero maintenance watch. No winding. No calendar resetting. No fussing.
Steve Cary
I have owned and repaired quite a few solar or kinetic charging watches, and personally I have learned to dislike them. If you collect watches and have several around that need to be kept charged, it becomes a nuisance. Also, despite all the claims to the contrary, they all need a new cell after 10-15 years, no exceptions. The cell is somewhat expensive and sometimes difficult to replace. I try to avoid buying them now. Just my opinion/observation. Steve
Mats Moberg
Hello, I own a pretty expensive German Junghans radio-controlled solar watch. I’m very pleased with its appearance, but it has a recurring fault, which makes it impossible for me to rely on it. Every now and then, the watch is suddenly a couple of minutes slow (typically 3 or 5 minutes). It’s only the minute hand that is affected; hour and second hands run ok. This only happens when I’m actually wearing the watch. If I just put it on a table where it gets a fair amount of daylight, it works beautifully. I have a feeling that the problem typically happens when I’m driving. I’ve sent it back to Junghans for them to check it, and they find no problem with it (nor do I, as I said, if I just leave it on a table). There’s nothing wrong with the automatic setting of the watch, so it corrects itself after midnight if the problem has occurred, but it’s obviously a nuisance if your supposedly absolutely accurate watch is several minutes behind. Is there anybody who recognises this problem?