Picoclick miniature LiPo battery

Features

• Typical capacity:
  • 30mAh for the 4mm cell (minimum 25mAh)
  • 20mAh for the 3mm cell (minimum 15mAh)
• Solderable nickel tabs (the tab with the small dots is the positive terminal)
• W x L: 10.0×12.0mm ±0.5
• Height: 4.0mm or 3.0mm ±0.2
• Nominal voltage: 3.7V
• Charge termination target: 4.2V
• Discharge termination voltage: 3.0V
• Typical charge current: 0.5C
  • 15mA for the 4mm cell
  • 10mA for the 3mm cell
• Max. charge current 1C
• Weight: <1g
• Max. discharge current: 2C

What can I do with one of these batteries?

Lithium ion and lithium polymer batteries are currently the most used batteries in rechargeable consumer electronic products. Your smartphone contains one, as do notebooks and many electric cars. What we mean is that your imagination is probably the limit.

These ones are really tiny ones that are designed to operate in low power devices like the Picoclick. Based on @maker.moekoe’s measurements, one of the 30mAh cells should last about 300 clicks in a typical Picoclick application, the 20mAh cell should last about 1/3rd less.

Be aware that these cells do not have any inbuilt protection!! This means that in order to operate safely you have to take some provisions. Here are some requirements for a fitting protection circuit:

• Charge termination at 4.2V ±0.05V
• Overcharge detection at 4.275±0.025V
• Discharge termination at 3.00±0.10V (in order to ensure long cell life)
• Overdischarge protection detection at 2.5V±0.10V
• Overcurrent/Short circuit protection at 0.5A

The cell manufacturer rates both for 500 cycles (specified as 70% of the initial capacity remaining after 500 cycles in a 0.25C charge/discharge test with a 3.0V discharge cut-off).

Soldering to the battery terminals can be done, but should be quick and as low temperature as possible. Be careful to not short the cell while handling it!