MCCI Blog

Subscribe to feed Viewing entries tagged batteries

Getting power from coin cells

Posted by Terry Moore
Terry Moore
 
User is currently offline
on Friday, 02 December 2011
in Uncategorized

Buried on TI's website, there's a very nice white paper on practical considerations for getting power from coin cells: "Coin cells and peak current draw," http://www.ti.com/lit/wp/swra349/swra349.pdf.

The author, Mathias Jensen, obtained CR2032 coin cells from a variety of vendors, and tested how much energy could be obtained in a variety of circumstances.  His key findings:

  • CR2032 cells have varying real capacities (based on the vendor).
  • Because of internal resistance, if you need bursty power, you should add a capacitor that can be trickle-charged at low current.

Out of politeness, he probably didn't mention some important additional conclusions:

  • Customers are going to buy batteries based on convenience and price, not based on vendor.
  • Many batteries don't nearly acheive their rated capacities in real-world tests.
  • If you want your customers to be satisfied, you have to design for the worst-case battery, not for the best-case.
  • Careful design for the worst-case battery can result in 1.4 times the battery capacity with low-quality batteries.

This is the kind of detail that, properly attended to, makes the difference between products that are loved, and products that are merely used.

Hits: 2325 0 Comments
0 votes
Legal and Copyright Information