Standard Charging LFP Battery

The research, published in the Journal of Electrochemical Society, tested LFP cells across different charging ranges and temperatures. Cells cycled between 75 and 100 percent state of charge degraded faster than cells kept lower. Some lost 24 percent capacity over what the researchers called a 10-year equivalent of use.

Carol Greider, who won the Nobel in 2009, has been vocal about battery research transparency. She did not comment on this particular study. But in previous interviews she has argued that automaker recommendations often prioritize user experience metrics over longevity data that takes years to gather.

Tesla's official line has not changed. The company's support page still says LFP owners should keep their charge limit at 100 percent and hit a full charge at least weekly. Tesla says this helps the battery management system estimate range accurately.

Pedro Lima runs PushEVs, a site that tracks battery industry developments from Portugal. He has written that Tesla's recommendation exists because LFP voltage curves are flat. The BMS struggles to calculate remaining charge when voltage barely moves between 30 and 70 percent. A full charge gives the system a reference point.

The study came out of a lab that has received Tesla funding in the past. The authors disclosed this. They also noted that degradation from full charging, while real, lands within warranty parameters for most drivers. Tesla's battery warranty covers 8 years or 100,000 miles with retention above 70 percent capacity.

On the Tesla Owners Online forum, a thread about LFP charging habits has run to 47 pages since 2021. One user who goes by the handle "evdoctor" wrote that he charges his Model 3 Standard Range to 80 percent on weekdays and 100 percent on Sundays. He called this a compromise between what Tesla recommends and what the battery chemistry literature suggests.

Recurrent, a Seattle company, collects battery data from thousands of EV owners who install their app. Their dataset shows LFP Tesla drivers charge past 90 percent far more often than owners with NCA packs. Most LFP vehicles sit between 90 and 100 percent. Most NCA vehicles sit between 50 and 90 percent.

Ford puts LFP in the base Mustang Mach-E. The company recommends a full charge once a month rather than once a week. Ford has not commented on the study.

Rivian started offering an LFP option on the Standard trim R1S and R1T this year. The pack is 92.5 kWh. EPA range is 270 miles. Rivian's guidance on charging habits has not been published.

The study authors wrote that drivers who leave their cars parked for days or weeks should consider keeping the battery lower. High voltage sitting in a parked car creates the same harmful reactions as cycling, just slower.