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An old, worn wristwatch with a scratched case

Automatic vs solar

Automatic vs solar watch

One can be rebuilt forever and costs something every few years. The other costs almost nothing and is replaced when it fails. Here is how to choose.

By Sawyer V. · Published

The short answer

Solar if you want the lowest running cost and the best accuracy: no battery changes and, from Citizen, five years of warranty. Automatic if you want a watch a watchmaker can rebuild indefinitely, at a published $176 to $296 per Seiko overhaul. The Seiko Alpinist SPB317 and the Citizen Garrison are the best of each here.

Automatic and solar are the two ways to own a watch without a battery on a schedule, and they get there from opposite directions. An automatic winds itself from the motion of your wrist and can be taken apart and rebuilt indefinitely. A solar watch is quartz charged by light: far more accurate, nearly free to run, and built around a module that is replaced rather than repaired.

Side by side

AutomaticSolar
PowerYour wrist's motionAny light
Published accuracy+25/-15 sec/day (Seiko 6R)±15 sec/month (Seiko V192)
ServiceAbout every three years; $176-296 (Seiko)$163 V-series service (Seiko)
If left unwornStops after its reserve — 40 to 80 hours hereSix months on a full charge (Seiko V192)
RepairRebuilt, for as long as parts existModule replaced
Longest warranty here5 years (Citizen NJ0150)5 years (Citizen Eco-Drive)

On prices: we publish no figure we have not verified today, so every buy button reads "Check price on Amazon". Service prices quoted here are the manufacturers' own published figures.

How we picked

We have not worn these watches. What follows is what we checked instead, on documents you can open yourself — the same criteria, in the same order, on every roundup on this site. The full method is on the methodology page.

  1. 01Running cost

    Seiko publishes $176-296 per automatic overhaul, about every three years, and $163 for V-series solar service. Citizen publishes no service prices.

  2. 02Accuracy

    Seiko publishes ±15 seconds a month for its V192 solar and +25/-15 seconds a day for the 6R automatic.

  3. 03Lifespan

    An automatic lasts as long as parts exist; a solar module is replaced when it fails, and its future depends on the maker.

  4. 04Warranty

    Citizen's Eco-Drive five years; Seiko three either way.

Disclosure · Some links below are Amazon affiliate links. If you buy through one we earn a commission at no extra cost to you. It does not decide what goes on this page or in what order — here is exactly how that works.

Quick picks

Ranked on the Keep Score below — six published specifications, weighted identically on every page. The last row is the one we would not buy.

#WatchBest forKeep ScorePrice
1

Seiko Prospex Alpinist SPB317J1

6R35, sapphire, 200m, $296 overhaul.

The automatic to buy9.6/10
Check price
2

Hamilton Khaki Field Auto 38mm H70455533

80 hours, Nivachron, sapphire, 38mm.

The automatic that forgives a weekend off8.6/10
Check price
3

Citizen Garrison BM8560-53E

Sapphire, Super Titanium, 100m, five years.

The solar watch to buy7.9/10
Check price
4

Seiko Prospex Speedtimer Solar Chronograph SSC947

V192 solar chronograph, sapphire, 100m, $163 service.

Solar with a published service price7.7/10
Check price
5

Citizen Promaster Diver BN0200-56E

Super Titanium, 200m, five years.

Solar and titanium at 200m6.8/10
Check price
—

Citizen Promaster Skyhawk A-T JY8078-52L

Solar at its most complicated — a module with a finite future.

Skip this one

Not if the point is to keep it8.3/10
Check price

Keep Score is arithmetic, not opinion — six published specifications, weighted the same way on every page. The formula is on our methodology page, so you can re-run it yourself.

01

Seiko Prospex Alpinist SPB317J1

Best for: The automatic to buy

9.6/10

Keep Score

Crystal
2.5/2.5
Serviceability
2.5/2.5
Water resistance
1.5/1.5
Warranty
1.05/1.5
Strap standard
1/1
Cost-to-keep transparency
1/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

A named 6R35 with a published accuracy tolerance and a published $296 overhaul, behind sapphire and rated 200m — an automatic you can plan to keep.

70 hours of reserve and three years of warranty.

This is where Seiko starts publishing an accuracy figure (+25/-15 seconds a day) and fits sapphire. A 6R35 overhaul is $296 against $176 for a 4R36 — a real difference, and one you can plan for.

Manufacturer specifications for the Seiko Prospex Alpinist SPB317J1
MovementSeiko 6R35, automatic with manual winding, 24 jewels, +25/-15 sec per day
Power reserve70 hours
Case41mm stainless steel
Lug-to-lug46.9mm
Thickness12.3mm
Lug width20mm
Crystalsapphire
Water resistance200m
Warranty3 years

Specifications read from Seiko Watch Corporation product page, SPB317J1.

02

Hamilton Khaki Field Auto 38mm H70455533

Best for: The automatic that forgives a weekend off

8.6/10

Keep Score

Crystal
2.5/2.5
Serviceability
2.5/2.5
Water resistance
1.1/1.5
Warranty
0.7/1.5
Strap standard
1/1
Cost-to-keep transparency
0.8/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

80 hours means it is still running on Monday, and the Nivachron hairspring addresses magnetism — the two usual complaints about living with an automatic.

Two years of warranty and no US service price.

Mechanically identical to the Murph and usually cheaper, because it does not carry a film's name. 47mm lug-to-lug on a 38mm case is a genuinely versatile footprint.

Manufacturer specifications for the Hamilton Khaki Field Auto 38mm H70455533
MovementHamilton H-10, automatic, Nivachron balance spring
Power reserve80 hours
Case38mm stainless steel
Lug-to-lug47mm
Thickness11mm
Lug width20mm
Crystalsapphire
Water resistance100m
Warranty2 years

Specifications read from Hamilton product page, H70455533.

03

Citizen Garrison BM8560-53E

Best for: The solar watch to buy

7.9/10

Keep Score

Crystal
2.5/2.5
Serviceability
1.4/2.5
Water resistance
1.1/1.5
Warranty
1.5/1.5
Strap standard
1/1
Cost-to-keep transparency
0.4/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

Light-powered, sapphire, a Super Titanium case and Citizen's five-year warranty — the solar case at its strongest.

Citizen publishes neither the thickness nor the lug-to-lug.

Sapphire is the upgrade the 37mm Chandler never got, on a Super Titanium case with Citizen's five years of cover. Citizen publishes neither the thickness nor the lug-to-lug, so try it on before you commit to 42mm.

Manufacturer specifications for the Citizen Garrison BM8560-53E
MovementCitizen E101 Eco-Drive, light-powered
Power reserveNot published
Case42mm super titanium
Lug-to-lugNot published
ThicknessNot published
Lug width22mm
Crystalsapphire
Water resistance100m
Warranty5 years

Citizen's five-year limited warranty excludes the power cell, case, bracelet and strap.

Specifications read from Citizen Watch product page, BM8560-53E.

04

Seiko Prospex Speedtimer Solar Chronograph SSC947

Best for: Solar with a published service price

7.7/10

Keep Score

Crystal
2.5/2.5
Serviceability
1.4/2.5
Water resistance
1.1/1.5
Warranty
1.05/1.5
Strap standard
0.6/1
Cost-to-keep transparency
1/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

Seiko publishes both the accuracy — ±15 seconds a month — and the service price, $163, for this solar chronograph: the only solar watch on this site with a published service figure.

The 21mm lug width is the annoyance.

Seiko lists V-series solar service at $163 — cheaper than a 4R36 overhaul and far cheaper than a mechanical chronograph. The 21mm lug width is the annoyance: standard straps come in 20 and 22.

Manufacturer specifications for the Seiko Prospex Speedtimer Solar Chronograph SSC947
MovementSeiko V192 solar chronograph, +/-15 sec per month, six-month run when fully charged
Power reserveNot published
Case41.4mm stainless steel
Lug-to-lug45.9mm
Thickness13mm
Lug width21mm
Crystalsapphire
Water resistance100m
Warranty3 years

Specifications read from Seiko Watch Corporation product page, SSC947.

05

Citizen Promaster Diver BN0200-56E

Best for: Solar and titanium at 200m

6.8/10

Keep Score

Crystal
1/2.5
Serviceability
1.4/2.5
Water resistance
1.5/1.5
Warranty
1.5/1.5
Strap standard
1/1
Cost-to-keep transparency
0.4/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

A 200m Super Titanium diver on light power with Citizen's five-year warranty — nothing to wind and nothing to change.

Mineral glass, and 44mm across.

Citizen's Super Titanium is surface-hardened, which is the point — plain titanium marks more easily than steel, and this does not. It is the closest thing on this list to a watch you can stop thinking about.

Manufacturer specifications for the Citizen Promaster Diver BN0200-56E
MovementCitizen E168 Eco-Drive, light-powered
Power reserveNot published
Case44mm super titanium
Lug-to-lugNot published
ThicknessNot published
Lug width22mm
Crystalmineral
Water resistance200m
Warranty5 years

Citizen's five-year limited warranty excludes the power cell, case, bracelet and strap.

Specifications read from Citizen Watch product page, BN0200-56E.

Skip this one

Citizen Promaster Skyhawk A-T JY8078-52L

Best for: Not if the point is to keep it

8.3/10

Keep Score

Crystal
2.5/2.5
Serviceability
1.4/2.5
Water resistance
1.5/1.5
Warranty
1.5/1.5
Strap standard
1/1
Cost-to-keep transparency
0.4/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

The Skyhawk is solar at its most impressive: radio-synchronized, a chronograph, a perpetual calendar and 200m behind sapphire.

All of it lives in one module. When the module stops being made, the watch is finished — the solar trade-off at its sharpest. If you choose solar to stop thinking about the watch, choose a simple one like the Garrison above.

It sets itself by radio, runs on light and is rated to 200m behind sapphire — and it is a module, not a movement. When the module stops being made, the watch is finished, however good the case still is.

Manufacturer specifications for the Citizen Promaster Skyhawk A-T JY8078-52L
MovementCitizen U680 Eco-Drive, light-powered, radio-synchronized to 43 cities, chronograph, perpetual calendar, dual time
Power reserveNot published
Case45mm stainless steel
Lug-to-lugNot published
ThicknessNot published
Lug width22mm
Crystalsapphire
Water resistance200m
Warranty5 years

Citizen's five-year limited warranty excludes the power cell, case, bracelet and strap.

Specifications read from Citizen Watch product page, JY8078-52L.

Which to buy

  • Automatic if you want a watch that can be rebuilt for decades and will budget for servicing — the published prices are here.
  • Solar if you want the most accurate, lowest-cost watch you never have to think about — the best solar watches are ranked.
  • A simple solar over a complicated one. The fewer functions a module carries, the less there is to fail.

The wider quartz question is covered in automatic vs quartz.

Questions people actually ask

Is a solar watch better than an automatic?

It is more accurate and cheaper to run: Seiko publishes ±15 seconds a month for its V192 solar and $163 to service it. An automatic can be rebuilt indefinitely, which a solar module cannot.

How long does a solar watch last?

As long as its module is supplied. The rechargeable cell is the part that wears — Citizen's warranty excludes it — and the module is replaced rather than rebuilt.

Do automatic watches last longer than solar?

They can. An automatic lasts as long as parts exist for its caliber; how long automatic watches last explains why.

Which is cheaper to own?

Solar. Over twenty years a Seiko 4R automatic costs $1,056 in published servicing; solar quartz costs a few hundred dollars at most on the cost of ownership arithmetic.

Sources

Every specification and figure on this page came from one of these documents. Where a manufacturer does not publish something, the page says so rather than filling the gap.

Read next

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