Ikea Ladda YH-990BF





Ikea does not only sell furniture, but does also have some other stuff. With some help from Sweden I got this charger to test.



The charger is packed in blister pack with the charger on one side and the mains cable on the other side.



There box contains the charger, mains cable and a manual in 26 languages.



The charger has build in power supply and is universal voltage (100-240VAC 50/60Hz).



There is no buttons on the charger, only a single indicator. It is red when any of the four channels is charging and changes to green when all channels are idle.
I.e. it is not possible to know if one battery is finished, only if all batteries are finished.




The charger uses a two-step connection for AA and AAA batteries and will automatically change charge current depending on battery size.






Measurements

• Discharge battery with less than 0.1mA when power is disconnected.
• Charge battery with about 12mA in trickle current, when charging is done.
• Charge will restart charging after power loss or battery insertion.
• The led is common for all four batteries and will first turn green when all are charged.
• It takes about 10 minutes to detect a full battery.

The charger uses a 1A charge current and a -dv/dt termination. When charging only one battery the charger is fairly cool, except when terminating (Exactly as expected).





There is not much difference between the four channels.



The eneloop XX takes a bit more time to charge.



With AAA batteries the current is reduced to 0.5A for the last part of the carge, as can be seen on the curves below this is done with pwm.



The charger uses -dv/dt to detect a full battery, this means it takes about 10 minutes to detect if charging is tried on a full battery.



With four batteries the charger gets fairly warm.



M1: 51,4°C, M2: 43,4°C, M3: 47,2°C, M4: 46,7°C, M5: 43,3°C, HS1: 58,3°C



The charger is fairly fast to start when powered up.



During charge it turns the current off each other second to check the voltage.



With AAA cells it uses pwm to half the charge current.



The trickle is pulses, but at a fairly low current and the average trickle charge is also at a fairly low level with 12 mA.


Testing the mains transformer with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



Conclusion

The charger does a good job of charging NiMH batteries with correct -dv/dt algorithm and has a nice low trickle current.
I would have liked it cooler, but that is very difficult to do with a small charger than can charge four batteries at 1A. I would also very much have liked to have a indicator for each channel, not only a common indicator.
I will call this a simple and good charger.



Notes

The charger was supplied by an open minded fan from Sweden for review.

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