WF 138 5.2V charger output

[Abe]

This charger has a selector switch that allows for charging of 3.6v and 3.0v batteries, if I test it unloaded then it reads 5.2v on the multimeter, I would have thought this too high for the batteries to be charged at? I must be missing something here, can someone explain this to me please?

 

[Rocketman]

Open circuit voltage may be higher. I would monitor cell voltage to see it it goes over 4.20 (with selector at 3.6).

Call it defective if cell voltage goes over 4.2. and stop it immediatly.
Some chargers have a sense voltage (not trickle charge voltage) to determine type and size of cell inserted.