I have the latest version of the Battery Tender Plus and it terminates the constant voltage phase (Green LED Flashing) earlier than expected. The orig inal design appears to have been an analog design and the manual showed the constant voltage phase ending when current declined to 0.1 amps. My tests on the new design show the constant voltage phase ending when the charge cu rrent has declined to 0.8 amps. Testing was done with an automotive battery in good condition.
Does the change from 0.1 amps to 0.8 amps sound like a concern? The manual refers to bulk mode, absorption mode, and float mode charging but no longer includes a specification or chart showing the current cutoff threshold.
I'd be interested if others have taken any measurements on either design. M y device charges at 1.25 amps and the constant voltage phase starts when th e voltage reaches 14.5 volts. The float voltage measures 13.1 volts.
Saturation might still be possible in float mode given enough time dependin g on the float voltage.
The latest design uses switching technology. The charger does appear to be more efficient with AC power measuring a maximum of 24 watts. The power lev el declines to 16 watts at the end of the constant voltage phase and then d rops to a very low level in float mode.