RC-Monster Forums - View Single Post - Higher pinions = safer MMM's? Or no? Someone's lying....

BrianG · 11.03.2009, 01:02 PM

I'm curious how chargers do this. Resistance can change even over the course of a charge/discharge cycle so that would mean the charger would have to monitor pack voltage while applying the charge current in on/off cycles over the course of the charge, apply the resistance formula (r=(V_unloaded-V_loaded)/A), and then plot the curve. Or do these chargers simply measure the ir at the start of the charge?

Also, doesn't the ir change dramatically at near the cells max discharge rating? So, the ir value you see when charging at 1C may not be even near the value at 20C.

	(#7)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	11.03.2009, 01:02 PM I'm curious how chargers do this. Resistance can change even over the course of a charge/discharge cycle so that would mean the charger would have to monitor pack voltage while applying the charge current in on/off cycles over the course of the charge, apply the resistance formula (r=(V_unloaded-V_loaded)/A), and then plot the curve. Or do these chargers simply measure the ir at the start of the charge? Also, doesn't the ir change dramatically at near the cells max discharge rating? So, the ir value you see when charging at 1C may not be even near the value at 20C.