CR2032 vs ML2032: why solar devices need the rechargeable one

CR2032 vs ML2032

The CR2032 and ML2032 share a case, 20 mm by 3.2 mm, and a nominal 3 volts. The CR2032 is a primary cell holding 220 to 240 mAh. The ML2032 is rechargeable and holds about 65. Solar keyboards and solar watches charge their cell, so they need the ML.

CR2032 vs ML2032 at the same scale: both 20 mm across, 3.2 mm thick.

	CR2032	ML2032
Chemistry	Lithium manganese dioxide (Li/MnO2)	Lithium manganese rechargeable (3 V)
Voltage	3 V	3 V
Diameter	20 mm	20 mm
Height	3.2 mm	3.2 mm
Capacity	220-240 mAh	65 mAh (rechargeable)
Also sold as	DL2032, ECR2032, 5004LC, KCR2032	–

This pair answers a question people ask constantly: how can a device recharge a coin cell that looks exactly like a CR2032? It cannot. Devices such as the Logitech K750 keyboard and many Casio solar watches ship with the ML type, whose manganese-lithium chemistry accepts around 3.0 volt trickle charging from the panel. The CR2032 is a primary cell and must never be charged.

Fit a CR2032 into one of those devices and the charging circuit works on a battery that cannot take a charge, which can cause it to leak or rupture. That is the one direction of this swap that is genuinely dangerous, not merely disappointing. Check the code printed on the cell you removed and on the battery door before ordering.

The reverse swap is safe but poor value. An ML2032 in an ordinary CR2032 device runs on roughly a quarter of the capacity and, with nothing to recharge it, dies quickly. Note also that the LIR2032 is a third member of this family: a 3.6 volt lithium ion cell in the same case, with a different charge profile, and not a substitute for either of these.

Frequently asked questions

Can I put a CR2032 in a solar keyboard or solar watch?

No. Those devices charge the cell, and charging a primary lithium coin can make it leak or rupture. They are designed around the rechargeable ML2032. If the battery you removed is marked ML, replace it with an ML, even though a CR2032 drops into the same holder.

Can I use an ML2032 in place of a CR2032?

It is safe, but it holds about 65 mAh against 220 to 240, so it lasts roughly a quarter as long and nothing in the device will recharge it. Use it only to bridge a gap, then fit the correct primary cell.

Is the ML2032 the same as the LIR2032?

No. Both are rechargeable coin cells in the 20 by 3.2 mm case, but the ML runs at 3 volts and the LIR at 3.6, with a different charge profile. Fitting an LIR where an ML belongs overvolts a circuit designed for 3 volts. Match the exact code.