I don't have the Nitecore D2/4 charger (I have an i4 though) so I can't be sure, but I seem to remember from the specs that the information shown is quite rudimentary. I have a Shoshine h2-v2 (one bay has given up after half a year's use though) that in addition to voltage and how long the battery's been charging shows how much mAh has been charged. Much more useful than the D2/4 in my opinion. I've also ordered an Opus diagnosing charger with much more features. In all honesty, I don't see much use in the D2/4's display, but perhaps someone who has it can enlighten us?