“Bad” is relative, but it does reduce the long-term lifespan of your battery. Ideally you should charge to 80%, but if you actually need the 100%, I wouldn’t worry about it either.
My phone has a option in battery settings for setting max charge to 80%.
This is what I do. I allow it to go to 100% for traveling. I don’t need 100% charge when I’m around the house or at work with access to a charger.
Yes. 74% is the “average” point of diminishing returns to preserve the battery, according to Accubattery’s data. It tracks charging cycles and battery wear across many thousands of smartphones.
In fact, the reason many phones/gadgets don’t offer this feature (and that Apple sometimes charges to 100% in spite of the toggle) is likely planned obsolescence.
…To add to this, the actual charging threshold of the battery is a bit arbitrary and set by the manufacturer, as a tradeoff of capacity vs life. Fast charging is the same; charging quickly is hard on the battery, and the limits at different charge levels are configured as a “balance” between convenience and life.
…And sometimes they get those thresholds wrong.
Like Samsung rather infamously did for the exploding Galaxy Notes. Google did for the Nexus 6P. They pushed the batteries too hard and borked the phones.
Yes.
