I have a large(280ah) Lifepo4 cell and looks like the 3.3v rail is good from 2.8v to 3.5v for the heltec v3 board I have. I figured I would ask here, Any reason this is a stupid idea? Seems to be to simple and I feel like I am missing a catch…
This is for a node I am hoping to place on a hill and leave over the winter with no solar. Originally I was going to use a 12v battery with a Buck converter plugged into the USB port.
I just started doing some testing with a Heltec V3 (Mine is not the Lite version though) and measured the average current consumption at 100mA when the unit is not transmitting.
If your unit never transmits and you get the full capacity of the battery that is only about 116 days of runtime.
Keep in mind extreme cold temperatures can be bad for lithium batteries. I’m not sure about how it affects LifePo4 but with other chemistries it can actually stop the battery from putting out a useful voltage until it warms back up.
Only other thing I would recommend is putting an appropriately sized fuse in line with the power cord. With a battery of that size if something were to fail on the PCB it could easily cause a fire
I see 100ma on my heltec v3 as well when setup as Client. If you switch it to router I see mine drop to around 10ma when idle.