This week a reader asks two specific questions about charging batteries.

1. Are faster chargers harder on batteries than slower chargers (for example, is a 20W charger harder on a battery than a 12W charger)?

2. Are more partial charging sessions (for example, to only 50%) harder on a battery than fewer charging sessions to 80%? Is it, for example, hard on a battery that’s at 35% capacity to recharge it to only 60%, resulting in more charging sessions than waiting for the battery to drop to 20% before charging it to 80%? Are those partial charges hard on the life of the battery? Would a battery always kept between 20% and 80% last longer than a battery more frequently charged between 30% and 60%? Is there an advantage in waiting to 20% before charging?