Author Topic: OAK low power Sleep  (Read 14538 times)

BobC

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Re: OAK low power Sleep
« Reply #15 on: August 23, 2015, 11:30:11 pm »
The first thing you need are the constant-current discharge curves for the NiMH cells you plan to use.  Not all battery datasheets provide constant current discharge curves, but this one for an Energizer 2300 mah NiMH AA does.

Second is an estimate of your average current use.  If your Oak/Acorn never sleeps and very briefly transmits once each hour, then you can take a guess at 70ma.

Next, verify if the constant-current discharge curves consistently deliver the rated mah.  The above Energizer does, so for these batteries feeding a linear regulator, the math is simple:

    Hours use = cell mah rating / average current use = 2300 / 70 = 33 hours use

Again, the above battery life is without any kind of sleeping, since I have no idea if the WiFi connection will tolerate a sleeping node without some heroics to precisely manage procotol configuration details.