(Adding tag) I have often heard that drawing pulses of more than about 15 mA from a CR2032 coin cell will permanently degrade its capacity. But TI has done the experiment and claims up to 30 mA with minimal change in battery capacity: http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=3Ds= wra349 Battery internal resistance is still the enemy, though. =A0A big capacitor can help hold up the voltage during the current peak. Looks like all testing was at room temperature too, which seems like a big limitation. =A0Also interesting is the difference between claimed and actual performance. (spoiler: Sony good, noname bad). Regards, Mark markrages@gmail -- Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com --=20 Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .