The ML2032 is a 3 volt rechargeable lithium coin cell in the familiar 20 by 3.2 mm case, rated about 65 mAh. Solar keyboards and solar watches use it because their panels can trickle-charge it, something a primary CR2032 must never be subjected to.
ML2032, face and side profile, drawn to scale: 20 mm across, 3.2 mm thick.
Voltage
3 V
Size (D×H)
20 × 3.2 mm
Chemistry
Lithium manganese rechargeable (3 V)
Capacity
65 mAh (rechargeable)
Compatible replacements
CR2032: Primary cell of the same size and voltage. A CR2032 must never be fitted where the device charges the battery.
LIR2032: 3.6 V li-ion in the same case; different chemistry and charge profile, not a substitute.
⚠️ Never install a primary CR2032 in a solar or self-charging device that specifies the ML2032; charging a non-rechargeable lithium cell is a rupture hazard.
Buying and replacement notes
The ML series is the answer to a common confusion: how can a device recharge a coin cell that looks exactly like a CR2032? It cannot; devices like the Logitech K750 keyboard and many Casio solar watches ship with the ML type, whose manganese-lithium chemistry accepts about 3.0 volt trickle charging. Fit a CR2032 into one of these and the charging circuit may cause it to leak or rupture. The reverse swap merely leaves the ML cell undercharged and short-lived.
Commonly used in
solar keyboards (Logitech)solar watches (Casio Waveceptor and similar)backup power in clocks
⚠️ 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.
Frequently asked questions
What is the difference between ML2032 and CR2032?
Same size, same 3 V nominal, completely different duty. The ML2032 is rechargeable and built to absorb trickle charge from solar panels; the CR2032 is single-use and dangerous to charge. Devices specify one or the other, and the swap is unsafe in one direction.
My solar keyboard is dying quickly. Is the battery replaceable?
Usually yes. In Logitech solar keyboards the ML2032 sits in a small tray; after five-plus years its capacity fades and a fresh ML2032 restores weeks of dark-running time. Buy the genuine Maxell ML2032, and avoid sellers shipping mislabeled CR cells.
Why does my ML2032 die if I do not use the device?
ML cells self-discharge faster than primary lithium and rely on regular top-ups from the device's solar panel or charger. Leave a solar watch in a drawer for a year and the cell runs flat. Periodic light exposure is genuine maintenance for these devices.