CTL1616 battery: equivalents & specs
The CTL1616 is Casio's rechargeable solar watch cell: 2.3 volts nominal, 16 mm by 1.6 mm, about 18 mAh of lithium titanate chemistry. Tough Solar G-Shocks charge it through their dials, and no ordinary CR1616 can take its place.
Compatible replacements
- CR1616: Primary 3 V cell of the same size. Not interchangeable: wrong voltage in both directions and the CTL position is charged by the watch.
⚠️ Fit only a CTL1616 in Casio Tough Solar watches. A standard CR1616 has the wrong voltage, cannot be recharged and can damage the module.
Buying and replacement notes
This cell trips up more G-Shock owners than any other part. It shares the CR1616's dimensions but runs at 2.3 volts and is designed for continuous solar charging; a 3 volt primary CR1616 in its place can overdrive the module and will not recharge, dying within months. Panasonic makes the cell, and watch parts sellers carry it with the insulating spacers some models require. A solar G-Shock showing LOW after days in sunlight has usually worn out its CTL1616, a 10-to-15-year event.
Commonly used in
Need a replacement?
Shop CTL1616 batteries on Amazon →⚠️ Keep away from children. Swallowed button batteries, especially 20 mm lithium coins, cause severe injury within hours. If a child swallows one, call the 24/7 National Battery Ingestion Hotline (US) at 800-498-8666 or poison control at 800-222-1222 immediately. What every parent should know.