The "Truth" about cycle life and temperature.

[grizzzman]

"If you want the truth about LFP and the effects of temp and cycles."

 

[Dzl]

Very interesting video, thanks for sharing.

Do you know anything about who this guy is?

I see he also has an hour long video "LiFePO4 batteries 101" which I haven't watched, but its now on my 'to watch list.'

 

[grizzzman]

I highly recommend that you take the time to watch that class.

 

[Ceberha]

Very interesting, and consistent with the papers on the subject I read a few months ago.

 

[Dzl]

One thing I found interesting is that this guy makes the same assertion as the BattleBorn CEO did in Will's interview with him (that low temperature is more of a soft limit relative to C rate than a hard limit).



If I understand the chart correctly, wear and tear on the battery is roughly equal at 1C @ 10°C, 0.5C @ 0°C, 0.25C @ -10°C, or 0.1C @ -20°C

It would be interesting to see how the chart would look beginning with a more modest charge rate at a more comfortable temperature (say 0.5C @ 20°C) or beginning with the standard testing profile which I believe is 0.2C @ 25°C

 

[Ceberha]

One thing I found interesting is that this guy makes the same assertion as the BattleBorn CEO did in Will's interview with him (that low temperature is more of a soft limit relative to C rate than a hard limit).

View attachment 9581

If I understand the chart correctly, wear and tear on the battery is roughly equal at 1C @ 10°C, 0.5C @ 0°C, 0.25C @ -10°C, or 0.1C @ -20°C

It would be interesting to see how the chart would look beginning with a more modest charge rate at a more comfortable temperature (say 0.5C @ 20°C) or beginning with the standard testing profile which I believe is 0.2C @ 25°C

I wish he had included the source for those data (perhaps it was embedded below the video and I missed it). From the studies I looked at, many different test parameters need to be considered, and some showed more substantial degradation below freezing than this suggests. Nevertheless, the notion that this is a curve with no hard inflection point at freezing seems quite reproducible.

 

[Dzl]

I wish he had included the source for those data (perhaps it was embedded below the video and I missed it).

Agreed

From the studies I looked at, many different test parameters need to be considered, and some showed more substantial degradation below freezing than this suggests. Nevertheless, the notion that this is a curve with no hard inflection point at freezing seems quite reproducible.

Yeah, I think that (the bolded text) is the takeaway the author intended us to come away with. He does state that we should pay attention to the general trend not the specific numbers. But still it would've been nice if he gave more context and cited a source.

 

[EVpower]

Trojan battery illustrates a similar curve on charge current versus temperature in their Trillium specification manual. Looks like they have done their homework.

 

[orangeminnie]

I wish he had included the source for those data (perhaps it was embedded below the video and I missed it). From the studies I looked at, many different test parameters need to be considered, and some showed more substantial degradation below freezing than this suggests. Nevertheless, the notion that this is a curve with no hard inflection point at freezing seems quite reproducible.

Link for higher-quality version of this chart? This renews my wish for a charge controller that programmably rolls back the max charge rate with temperature.

 

[Dzl]

Link for higher-quality version of this chart?

If you are referring to screenshot I posted, unfortunately I don't have have a higher quality version of the chart (its just a screenshot from a youtube video I watched) But I do have a link to the youtube video I got it from.