I got my CEF23 yesterday and have been testing it in preparation for my trip to South Africa.
The AC-DC power-supply built into the charger is an archaic transformer-based design which gets quite hot. disappointing.
The USB-charge circuitry also seems to get
very hot in use, when USB-charging from batteries, it got so hot that it shut off along with a strong chemical smell.
Because the AC-psu is terrible, i have opted to use the charger solely with a 12V DC input, as provided by the power-supply that came with my XTAR WP2 Li-ion charger. This seems to work very well, although the CEF23's casing needed to be modified so the regular-length jack from the PSU would fit properly.
When using the USB-charge feature on the 12V DC input it still gets hot, albeit less so.
As a result i'm only going to use the USB charge feature in emergencies, and will only power the charger from the 12V input.
Otherwise it's good, and its charge termination detection is a damn sight better than my last NiMh charger