John61CT wrote:Far from authoritative source.
Actual numbers vary by the specific chemistry.
For LFP at the standard 25°C
0.4C or lower is best for longevity.
Many care more for saving time, say an EV scenario, happy to sacrifice life cycles, go up to 1C or even faster.
In racing, preheating cells to 90°C is common in order to make 3+ C-rates somewhat safe, but they are buying new packs ever season.
In sweater weather, no pre-heating I'd stick to 0.2C or slower.
Anywhere near freezing I would bring inside or do pre-heating.
I would like to see your source, battle born batteries wont charge or discharge over 135-140 or so degrees F, or about 57 degrees. their BMS wont allow it, if heating them to 90 C or 194 F helps them charge then why is one of the biggest makers making their batteries shut down at 134-140 degrees. The standard for almost everything is 25C or 77F, why because that normal room temp range. Again link at bottom says dont charge at high temp.
Do you really think Tesla would set their chargers to charge faster than the batteries can handle and loose capacity when they are warranting the batteries for many thousands of miles. Now granted tesla uses li ion not lifepo4. Even battle born says up to 1 c is fine, but .5c is preferred for longevity.
I do agree if close to freezing, bring inside or warm it up. Standbuy loss on a lifepo4 is about 2% amonth, so a battery at 75% stored for a year would be about 50% at the end of the year.
A few authoritative sources
https://youtu.be/mTeoweIkKgc
https://battlebornbatteries.com/faq/
https://batteryuniversity.com/article/b ... mperatures
