In talking to support about a warranty issue, they seem to indicate that it’s normal for the Librem 14 to need to charge overnight in order to complete charging. My other laptops seem to charge within a couple of hours.
Approximately how long do your Librem laptops take to charge fully when fully depleted?
Charging is normally slow at the low (<20%) and high (>80%) ends of the cycle to reduce battery wear, but it normally only takes about 9 hours for a full charge 0-100%, not 18 hours as you mentioned.
Actually, the slower a battery is being charged, the longer it will last. It has to do with the amount of current (Amp) that is being fed into the battery / per unit of time. Very fast charging equipment will kill your battery in no time!
I myself think that Purism took a wise conservative stance on charging time for their laptops - it is true that my Librem 15 also takes a very long time to charge when completely discharged, but its capacity is still 113% after several years of use (amazingly, this battery registered 117% of its rated capacity when I bought the laptop)
To be clear, I have the 3-cell battery, not the 4-cell battery. The latter will likely take 8-9 hours to fully power cycle, assuming it is in lightly used condition and at room temperature.