3 min read · Updated
Tough Solar Explained: How Solar G-SHOCKs Charge and How Long They Last
Short answer
Tough Solar is Casio's solar charging system: a solar panel in the dial charges a rechargeable battery from sunlight or indoor light. Casio says about 8 minutes of direct sunlight gives a day of power, and a full charge runs a GA-B2100 about 7 months or a GW-M5610 about 10 months with no light at all.
How does Tough Solar work?
A Tough Solar watch runs on a rechargeable battery that a solar panel in the face keeps charged. Casio's manuals explain that power is generated whenever the face is exposed to light, including indoor lighting.
How much light does a solar G-SHOCK need?
Very little. Casio says about 8 minutes of direct sunlight gives roughly a day of power, and normal daily wear keeps the battery topped up. When a watch is left in the dark, power saving blanks the display to stretch the charge.
How long does a full charge last?
Casio rates a fully charged GA-B2100 at about 7 months of normal use without light, the GW-6900U and GW-M5610 at about 10 months, and the GMW-B5000 at about 22 months in darkness with power saving on.
| Model | Display | Tough Solar | Multi-Band 6 | Bluetooth | Power |
|---|---|---|---|---|---|
| GA-2100 | Analog-digital | No | No | No | 3-year battery |
| GA-B2100 | Analog-digital | Yes | No | Yes | Solar, ~7 mo per charge |
| GM-2100 | Analog-digital | No | No | No | 3-year battery |
| GW-6900 | Digital | Yes | Yes | No | Solar, ~9 mo per charge |
| GA-700 | Analog-digital | No | No | No | 5-year battery |
| DW-5600 | Digital | No | No | No | 2-year battery |
| GW-M5610 | Digital | Yes | Yes | No | Solar, ~10 mo per charge |
| GMW-B5000 | Digital | Yes | Yes | Yes | Tough Solar |
| GA-V01 | Analog-digital | No | No | No | 10-year battery |
| G-7900 | Digital | No | No | No | 2-year battery |
How to charge a solar G-SHOCK
Leave it face up near a bright window for a few days, or wear it outdoors. Casio's manuals advise against charging where the watch can get very hot, such as on a car dashboard in direct sun.
- Store it in a lit room rather than a drawer.
- If the display is blank, it is likely in power saving: put it in light and it wakes up.
- A low battery indicator on solar models tells you when to give it more light.
Which G-SHOCKs are solar?
Of the models we cover, the GA-B2100, GW-6900, GW-M5610 and GMW-B5000 use Tough Solar. The GA-2100, GM-2100, GA-700, DW-5600, GA-V01 and G-7900 run on replaceable batteries.
FAQ
Do solar G-SHOCKs work indoors?
Yes. Tough Solar charges from indoor lighting as well as sunlight, just more slowly.
Is the GA-2100 solar?
No. The GA-2100 runs about 3 years on batteries; the GA-B2100 is the solar version of the same design.