Varta Microbattery – Miniature rechargeable NiMH button cells suited to battery back-up applications


VARTA Microbattery offers four series of rechargeable Nickel Metal Hydride (NiMH) button cells, giving designers a choice of energy-storage devices optimised for robustness, high- temperature operation at up to 85°C, or high power output.

The smaller NiMH cells are particularly well suited for use as a battery back-up for the Real-Time Clock (RTC) device found in many types of electronic systems. For instance, the small V 6 HR cell is highly reliable, offers a nominal capacity of 6mAh, and at just 2.15mm high easily fits on space-constrained circuit boards alongside low-profile surface-mount semiconductor components. Tolerant of a 0.18mA continuous over-charge current, the V 6 HR enables the designer to implement a simple charging circuit which continuously trickle-charges the cell.

All VARTA NiMH button cells include a built-in pressure vent to guarantee safe operation in the event of mistreatment. The cells also have a low rate of self-discharge, which means that they are ready for use without charging or special handling procedures even after an extended period of storage.

It is an inherent property of batteries that their capacity declines with use: the VARTA NiMH button cells have an extended product lifetime of more than 1,000 cycles.

The four series of NiMH button cells are:
• V..H series – robust cells with a discharge capability of up to 2CA.
• V..HT series – robust cells with high-temperature capability. Discharge capability of up to 2CA.
• V..HR series – high-rate button cell with a discharge capability of up to 5CA.
• V..HRT series – high-rate, high-temperature button cell with a discharge capability of up to 5CA.

All cells are UL recognised.


  • Tolerates deep discharge
  • Patented crimp sealing system eliminates risk of leakage
  • No memory effect


  • RTC battery back-up
  • Battery-backed memory
  • Industrial equipment
  • Healthcare equipment
  • Automotive systems
  • Wireless headsets and headphones