Recently I got a MC3000 charger. It is good for lithium-ion based batteries. But there is some problem when charging NiMH.
First problem is charger can't stop charging (HKJ's review also mentioned that). I used standard AA Eneloops. They always stop correctly on c9000 or BT-C2000 charger (when charging capacity reaches 1900-2000mAH. Current is 0.2A). But MC3000 will not stop even at 2500mAH (Current 0.2A, DeltaV set to -3mV & -2mV). Battery is already about 40°C and MC3000 seems will continue forever.
Second problem is the battery voltage. On MC3000, battery voltage rises to 1.53-1.54V when charging capacity is1900mAH (This is the position where c9000/BT-C2000 stop). As I remember, on c9000/BT-C2000, battery voltage never went above 1.5V (typically 1.47-1.48V when stop).
So my question for the first problem is, why MC3000 fails to detect the -deltaV? How to let MC3000 correctly stop when charging Eneloop (some other NiMH brands which correctly stop on c9000/BT-C2000 also have same problem).
For the second problem, the voltage difference may not be important, but I wonder why. Why there is such voltage difference? Is it because MC3000 uses constant current instead of pulsed current? If yes, why pulsed current leads to lower voltage? Which is better?
[edit]
Thanks HKJ. I've read his article on charging NiMH. It contains convinving experiment data/chart. Now I know why MC3000 is a good charger. I will make voltage termination program for NiMH.
The left question is pulsed charge VS CC charge, CC charge seems lead to higher off load voltage at same charge level. It is interesting.
First problem is charger can't stop charging (HKJ's review also mentioned that). I used standard AA Eneloops. They always stop correctly on c9000 or BT-C2000 charger (when charging capacity reaches 1900-2000mAH. Current is 0.2A). But MC3000 will not stop even at 2500mAH (Current 0.2A, DeltaV set to -3mV & -2mV). Battery is already about 40°C and MC3000 seems will continue forever.
Second problem is the battery voltage. On MC3000, battery voltage rises to 1.53-1.54V when charging capacity is1900mAH (This is the position where c9000/BT-C2000 stop). As I remember, on c9000/BT-C2000, battery voltage never went above 1.5V (typically 1.47-1.48V when stop).
So my question for the first problem is, why MC3000 fails to detect the -deltaV? How to let MC3000 correctly stop when charging Eneloop (some other NiMH brands which correctly stop on c9000/BT-C2000 also have same problem).
For the second problem, the voltage difference may not be important, but I wonder why. Why there is such voltage difference? Is it because MC3000 uses constant current instead of pulsed current? If yes, why pulsed current leads to lower voltage? Which is better?
[edit]
Thanks HKJ. I've read his article on charging NiMH. It contains convinving experiment data/chart. Now I know why MC3000 is a good charger. I will make voltage termination program for NiMH.
The left question is pulsed charge VS CC charge, CC charge seems lead to higher off load voltage at same charge level. It is interesting.
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