SparkFun Forums

[joe5939]

I read the Artemis OpenLog Hardware overview. I'm confused about the difference between 3V3 and the VBATT / GND pins. I would like to power it with a 3 Volt C2032. Advice on how to connect it? Use 3V3 and cut the MEAS trace?

At some point, I plan to have it connected to USB to read serial output if that makes a difference

Application:
Log IMU and load cell data once a minute for 8 hours.

Thank you kindly.

https://learn.sparkfun.com/tutorials/op ... e-overview

[PaulZC]

Hi joe5939,
Trying to power the OLA from a CR2032 sounds like a really bad idea...
Their voltage is typically 2.9V and parts of OLA will need the full 3.3V. (We use a voltage supervisor to detect when the battery is low and I suspect it will see a fully charged CR2032 as "low".)
Also, CR2032's can only deliver limited current, typically: 0.2mA continuous; 7mA pulsed. The OLA will draw much more than that.
Please consult the schematic for more details on the power circuit.
Best wishes,
Paul

[joe5939]

Thanks for the reply PaulZC. You've convinced me not to use the C2032. Can you explain the difference between 3V3 and the VBATT / GND pins?

My goal was to avoid the minimum 450 mAh LiPo battery suggested because it is too big for my application and I want it as safe as possible. If I use a 110 mAh battery and don't have it connected to the OpenLog while it's connected to USB power, will it be OK? I would charge the 110mAh on a separate charger (PRT-15217).

"Please make sure your battery capacity is at least 450mAh (0.45Ah); bad things will happen if you try to charge our smallest batteries at 450mA. "

[TS-Chris]

My goal was to avoid the minimum 450 mAh LiPo battery suggested because it is too big for my application and I want it as safe as possible. If I use a 110 mAh battery and don't have it connected to the OpenLog while it's connected to USB power, will it be OK? I would charge the 110mAh on a separate charger (PRT-15217).

You will need PRT-14380 set to 100mA to charge the 110mAh battery, but as long as you don't have the battery connected to the OpenLog Artemis and USB at the same time, you should be fine.

**Don't forget to remove the battery from the OLA before connecting a USB cable!**