How to test 12V automotive battery charger?

[Warp6]

I have an old Exide automatic battery charger that I'm not sure is charging properly. It's one of those that you just plug in and leave it. Has 2 slider switches.

Switch on left is for battery type and has 2 settings: 1-Deep cycle/maintenance free or 2- Regular/Gel

Switch on right is for charge type and has 4 settings: 1-6V 10amp, 2-12V 2amp, 3- 12V 10amp and 4- 12V 60amp engine start

On the left is a needle type guage that points to 3 batteries: Empty, half full and full.

I'd like to know the method for testing this thing with a voltmeter and what readings to expect.
Are readings taken while attached to a battery?

Thanks in advance, Craig

 

[garyk1970]

yes test w/volt meter. hook volt meter to battery first,then plug in batt charger.you should see the voltage increase(the amount depends on the condition of the battery) you should see at least 12 volts or more. but no more than 14.5....
HTH