Small Form factor battery powered?

[entity]

Hi

I'm considering looking into these Flutter modules. But I want it to be powered by cell batteries, to keep the formfactor low for my purpose (wearable). Is this doable, and how much batterylife can I expect?

[psp1024]

From Taylor's Reddit post (as I couldn't find anywhere else this was listed):
"10-40mA current draw (under normal use)"
This was a year ago from his AMA, so specs might have changed, but lets assume this is still roughly accurate, and let's also assume on the high end/worst-case battery life.

Using what is the correct math as far as I can tell, if we have a 1000mAh battery, then at a draw of 40mA it will last 25 hours. (1000mAh/40mA=25h). Now, what is the mAh of your button cell battery?

The Wikipedia page for batteries lists 'Typical Capacity' anywhere from 25-1000mAh.
The CR3032 is rated at 500mAh and is 30x3.2mm, and is 3 volts.
The CR2427 is rated at 1000mAh and is 24.5x7.7mm, also 3 volts.
These would last about 12.5 or 25 hours respectively, assuming that the Flutter would be okay receiving 3v instead of 3.3v (which I think it would be, but not sure).

Depending on what sort of battery life you're looking for, those appear to be decent options.

[jet_flyer]

I'd suggest using a lipo battery rather than a button cell. you can get much more MaH per volume and since the micro RC aircraft market has taken off recently there's a lot of very small batteries that are really cheap

[psp1024]

Excellent point, and obviously LiPo is rechargeable as well, saving on long-term costs. Single-cell LiPo's run at 3.7v, but probably aren't going to be quite as small as the button cells.
The smallest LiPo I found on Amazon (that still has enough mAh) is still quite bit bigger then the button cells we were looking at, but if it's able to be implemented would probably be better overall... especially since the Flutter Pro has a battery charging circuit if I remember correctly, so recharge with USB micro charger(?).

[tweir]

I'd recommend checking lipos from sparkfun & adafruit - they can get pretty small. Here's an example from adafruit:
https://www.adafruit.com/products/1317

[psp1024]

The problem being what I mentioned above though: 150mAh will only get you 4-6 hours. Most wearables are looking to last a lot longer then 4-6 hours.