The inadvisability of charging LiFePO4 batteries below 32F/0C (akabelow freezing)

Say what?

"Work" in an electrical circuit is volts and amps.
Double the volts, basically halve the amps.
Part of why some home equipment (eg, window AC unit) goes to 220VAC because the normal load is beyond a typical 15A breaker, maybe even beyond later 20A breakers.
Cost (buying the unit vs. running a dedicated 220VAC single phase circuit) vs. benefit.

Hmmmmm....let me think......inductive loads are a bit different. Resistive loads are fairly linear.
Coil or motor loads are on the inductive load end, they vary. They typically have an inrush current.
Resistive loads are fairly linear, they are what they are, minor variance based on temp.

OK, not arguing a field guy vs. an EE, way beyond the topic of this thread.

I will say I am looking for info about the "plating issue" in some battery chemistries, never heard that before, I may learn something new (which is a good thing......).

On Saturday, March 24, 2018 at 2:10:01 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
Say what?

"Work" in an electrical circuit is volts and amps.
Double the volts, basically halve the amps.
Part of why some home equipment (eg, window AC unit) goes to 220VAC because the normal load is beyond a typical 15A breaker, maybe even beyond later 20A breakers.
Cost (buying the unit vs. running a dedicated 220VAC single phase circuit) vs. benefit.

Hmmmmm....let me think......inductive loads are a bit different. Resistive loads are fairly linear.
Coil or motor loads are on the inductive load end, they vary. They typically have an inrush current.
Resistive loads are fairly linear, they are what they are, minor variance based on temp.

OK, not arguing a field guy vs. an EE, way beyond the topic of this thread.

I will say I am looking for info about the "plating issue" in some battery chemistries, never heard that before, I may learn something new (which is a good thing......).

For resistive loads, Ohms law rules: V=IR. Fixed resistance means if volts go up, current goes up. AC and inductive loads get complicated real fast. Transients are even more complicated. For things that draw power to do "work", like a DC starter motor, ignoring transients, then Power = VA, so at a fixed power if volts go up, amps go down. Inrush current on motors is actually limited because they are inductive. But stall current can be quite high as they look like a very small resistor.

It must be winter. I'm still looking for that scholarly paper that discusses LiFePo4 charging at low temps. Closest one I've found is a study to see how they work in a satellite, which spends half it's time on the dark side of the earth at very low temp (but doesn't charge much, there being no solar radiation....)