Charger Panasonic BQ-CC51E





Panasonic has a line of NiMH chargers, some are fast and smart, others dumb. This one here is a very slow and rather dumb charger. I got the charger together with the latest revision of Eneloop, they are tested separately.
I have tested this charger before, but Panasonic asked me to test this E version (I do not know if E is European or a new revision of the charger).



I got the charger in a blister pack. There was the charger, 4 eneloop batteries and a instruction sheet.
The instruction sheet specifies charge time for different cell capacities, from 5 hours for a 1000mAh AA to 12 hours for a 2500mAh AA, you are supposed to remove the batteries after that time.
The included batteries are Eneloop AA BK-3MCCE 1900mAh.



The charger is designed with a EU plug.



The only user interface is two leds, one for slot #1 & #2 and one for slot #3 & #4, i.e. the charger can only charge two or four batteries at a time.
The leds is green while charging and will flash on error. When charging is done they turn off.




The charger has the typically two level slots used for AA and AAA batteries.







Measurements charger

• When not powered it will discharge the battery with 0.05mA
• If the charger detect an error the green led for that channel group will flash.
• Steady green light is charging.
• Charge will restart charging after power loss, or battery insertion.
• Can only charge in pairs.
• Power consumption when idle is 0.22 watt

The two cells is fully charged and a bit more, using about 12.5 hours. This looks like the charger uses a fixed charge time.



There is no surprise with the second channel, it uses exactly the same time.



Using higher capacity cells fills the batteries and will not change the charge time.



Charging AAA cells will reduce the current and use the same time.



Starting with two full cells is not a good idea, they get another full 12.5 hour charge.



Four batteries do also take 12.5 hours to charge.



M1: 30,9°C, M2: 32,1°C, M3: 32,5°C, M4: 30,9°C, M5: 36,5°C, M6: 31,8°C, HS1: 36,7°C
The charger uses a fairly low charge current and the cells stays fairly cool during charge.



M1: 33,5°C, HS1: 37,0°C



M1: 41,2°C, M2: 44,3°C, M3: 44,4°C, M4: 41,4°C, HS1: 46,7°C
When the cells are full any further energy is wasted as heat in the cells and they will warm up.




The charger needs about 0.5 second to start. I wonder about the pulsing, because it do not need to measure the voltage to terminate.



4 cells uses exactly same charge pattern as two cells.

Testing the transformer with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

This charger do always need 12.5 hours before it says done.
It is not a good idea to charge full or half depleted batteries on this charger, it is best to charge only empty batteries.
I do generally not like this type of charger, it is hard on the batteries, because it always overcharge, but it will charge many old mostly worn out batteries.



Notes

The charger was supplied by Panasonic for review.

Here is an explanation on how I did the above charge curves: How do I test a charger