LIR2450 is a coin cell, Lithium-Ion rechargeable battery. Physically the same size as CR2450, LIR2450 can be used as a rechargeable replacement to CR2450 in most cases. This little battery has little over 100 mA/Hour capacity, with nominal 3.6 V output. LIR2450 battery is perfect for powering a small project.

The problem was that there were only poor quality chargers available for this very useful battery. Here's a good proof of how scarcely one of those charges can be: 

Since I could not find a good charger for it, I made one.

This charger is based on the popular MCP73831 by Microchip to charge Lithium-Ion battery safely. It is very compact and plugs right into an USB port.

Features/Notes:

• Compact design plugs into an USB port
• Charge/Done LEDs indicate the charge status
• Uses MCP73831 Lithium-Ion battery charger IC for precise control of charge current & voltage.
• Charge current: 45 mA typical
• Charge time: about 3 hours
• Dimension: 1.15 x 1.45 x 0.38 inches