I have a project where I need long battery life but I have very little room for a battery. On my prototype, the power consumption is between 8 and 12 milliamps and that lasts about 20-30sec then the device goes to sleep where it consumes about 0.01milliamps.
Currently I am using a CR123 battery but it is too large for the project. An other option is a coin battery CR2477 would work but a CR2032 would be better. In both cases, the standard current is in the 0.2amp range and I am concerned about he impact of the higher current on battery life.
Am I worrying for nothing? Is there a better battery choice? The Cr2477 give me a nominal 1000 mAhr but I could tolerate a smaller battery if it is commonly available so it can be replaced in the field.
Thanks for any comments.
Ian
Not sure what you mean by this:
In both cases, the standard current is in the 0.2amp range
Even the attempt to draw that much current from a cell like CR2032 will permanently damage it. You need to look very carefully at battery specifications when making this choice, and you may need to reconsider the overall design.
Sorry I meant 0.2 mA is the standard current on the battery when my project is in the 8-12mA range. 8-12mA is the maximum for the batteries
You may find this analysis of coin cell current draw versus battery life useful: http://www.ti.com/lit/wp/swra349/swra349.pdf
Per the report
"In addition,measurements show that different peak currents up to 30mA have minimal impact on
effective battery capacity. Bringing the average current down is therefore the most important
factor when maximizing battery life of CR2032 coin cells in low power RF applications. "
It would seem that I am ok.