Why do car manufacturers recommend only charging a battery to 80/90%?
In: 9
*All* (lithium ion) batteries should be charged to only ~80ish%. Many smartphones will have a setting that stops charging at 80%, and Windows 11 will discharge to 80% if it detects the laptop has been plugged in for a long time. Charging to full accelerates damage to the battery and reduces the lifetime more quickly.
I don’t know the exact chemistry of what’s happening, but I found an explanation [here](https://www.reddit.com/r/ebikes/comments/nzatsu/evidence_that_storing_liion_at_100_charge_causes/h1panws/)
Basically, heat is really bad for lithium ion batteries as it causes by-products that inhibit the chemical reactions that make the battery work. As the battery approaches full charge, the amount of reactants decrease, requiring more energy to force the reactions. That means more heat and therefore more by-products. Ultimately reducing the capacity of the battery.
For the same reasons, fast charging also causes more heat and more damage.
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