If you are refering to my post, realize that -DeltaV is only used after the cell has been nearly charged as seen by dV²/dt² and the charge current reduced. It's used when the charger is in "top off" mode. I think just reducing the charge current causes some voltage drop.
Actually I'm not sure if the criteria for ending top-off mode is -30 mv. Saitek doesn't reveal all it's secrets. It seems that the charger switches from top-off to trickle when the voltage drops by 30 mv from what it was when switching from fast to top-off. That's based on sitting there and staring at the voltage display. It's boring but it's easier than building a data logger
I guess I should mention that using this method instead of the delta temperature seems to work in cases where there is virtually no temperature rise. For instance if I charge a fully charged AA cell, the charger will go through all three charge phases and switch to trickle in about 5 or ten minutes. The cell stays almost at room temperature I think. (gotta build that data logger
)
Anyway I've been charging NiCad and NiMH this way for over 4 years and I see no ill effects. How warm the cells get depends on what I'm charging. I think the highest temperature I measured was 130°F (54°C). Maybe some day I will try to see if the highest temperature occurs during fast or topoff mode.