In the interests of minimizing weight, I'd like to use a coin battery in my project. Unfortunately, my project is going to need about 2mA, and I see from the data sheet of the Energizer CR2032 that its "continuous background drain" is a mere 0.19mA. However, it also says that 6.8mA are possible as a "pulse drain", and if I read this correctly, a "pulse" is a period of two seconds. As these things go, what can I expect from such a battery if I draw my 2mA for a period of, say, ten seconds? Would I be pushing the envelope there, or not really?
maximum practical current flow from a battery
Jun 08, 2007
1 Replies
As long as your pulse is smaller in magnitude than the one specified, I think it is safe to extend the time and lower the current, as long as the current, time product is not larger than the specified pulse rating.
Since the specified pulse rating is 6.8 mA times 2 seconds, for a product of 13.6 milliamp seconds, you should be safe pulling 2 mA for 13.8/2= 6.8 seconds. However, as the current approaches .19 mA, that time extends to the life of the cell. I also suspect that this surge rating includes lots of rest, so that the average current stays well below the .19 mA continuous rating. In your case, that means that for every 2 second pulse, there is a lot more than 20 seconds rest time before the next pulse, to let the chemistry catch up.
In the final analysis, you should run a load test on a few cells with your load and see in the voltage remains useful for a significant part of the cell's life.
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