Moteino Regulator Choice & Drain

[ichilton]

Jeelabs tried that here: http://jeelabs.org/2011/06/21/mcp1702-current-draw/

[smni]

Jeelabs tried that here: http://jeelabs.org/2011/06/21/mcp1702-current-draw/

Interesting! Ok, so it looks like that testing was done without any load on the output. But it seems to suggest that you probably don't need to input the full ~600mV above the 3.3V output to still get good performance with a low power project.

I'm mainly trying to decide how to handle powering a project with 3 AA batteries. Alkalines will drift down from a starting 4.5V and become unusable at around 3.3V when using the onboard regulator.

[KanyonKris]

I will be using 3 Eneloop AAAs, they have a flatter discharge curve that should work well with Moteino.

[smni]

Yes, Eneloops have a pretty flat discharge curve:
http://www.eneloop.info/fileadmin/web_data/Data-Sheets/HR-4UTGB.pdf

Energizer Ultimate Lithiums also have a very flat discharge voltage curve, and they work great at low temperatures if that's important:
http://data.energizer.com/PDFs/l92.pdf

The Energizer lithiums are pretty pricey though. But at 1200 mAh vs 800 for the standard Eneloops, they should last 50% longer. And even more at cold temperatures.