a new Model 18 owner here. Just in case it’s useful to anyone else, I enquired about the Model 18 charge indicator never showing full (all bars) and always being red. Jen was kind enough to explain: “This is quite normal- the four bars are never lit even when the battery is fully charged.”
Incidentaklly, for those that need a faster charging time we are now stocking some fast chargers which can be purchased on the Accessories page of our website. These will more than half the charging time.