Dave Martindale wrote:

There are two different types of cheap charger. They're both constant
current with no detection of end of charge. One type uses a low enough
charge rate that a full charge takes 14 hours; that's what you're
talking about. If the batteries start out partially charged, not
completely discharged, they will be overcharged - but at such a low
current that it won't hurt them.

From my reading, this seems to be somewhat cotroversial, some authors
and manufacturers claiming C/10, some C/20 and some saying even lower.
My MAHA 204 charges at C/60 after the end of the fast charge cycle.

It's probably on sacle of decreasing badness. :-)

Ted