Charger Rydbatt 16 NiMH JBC038-11






This is a 16 slot NiMH charger for AA and AAA cells.






I got the charger in a cardboard box with some Chinese writings on.



The pack included the charger and a power supply.



The charger has a 12V input for the power supply, it is rated for 2A.



There is two displays, each covering 8 slots and a button to trigger a discharge cycle.
The button must be held down to trigger the discharge cycle.



The battery symbols are animated while charging or discharging and a text shows what function is active.



Discharge mode.










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








Measurements charger

• When not powered it will discharge with less than 0.15mA.
• Power consumption when idle is 0.3 Watt, the power supply alone is 0.06 watt
• Charge will restart charging after power loss, or battery insertion.
• The charger has four charge channels, that is switched between the 16 slots.

Charge



The charger uses a -dv/dt (or 0dv/dt) termination and supplements with trickle charge. The termination is a bit slow, it takes more than a hour to detect a full battery. Average charge current is a bit below 0.5A

















It looks like the charger uses a charge circuit for each 8 battery, the charge current for the two sections are different.



On this fairly old cell the charging stops a bit early.



This cell looks fine.



The leise cell is also handled fine.



With AAA batteries the current is reduced to about 0.25A.



Usually the charger is very slow to detect when a battery is full, with a full battery it is faster, but still needs more than a half hour.



The 0.5A charge current is maintained with 16 batteries in the charger.



The charger uses up to 1.5A from a 12V supply.



M1: 39.5°C, M2: 42.5°C, M3: 41.8°C, M4: 38.5°C, M5: 32.0°C, HS1: 45.8°C




The charger is fast to start and uses a pulsing charge current.



There is a 2A pulse every 8 second, the pulse is about 1.7 second long.



Checking voltage on the 3 first slots, as can be seen the charger switches between them and also the fourth slot.
The next four slots are synchronous with the first four slots. The last 8 slots is in another group.



The trickle charge is done with similar pulses, but the time between them is 10 times longer, i.e. a 2A pulse every 80 seconds and it is about 1.7 second long, this means a average trickle current of about 40mA



Discharge



The discharge cycle will discharge all batteries and then charge them again.
With a single cell the discharge current is in the 0.6 to 0.7A range and the charger stops at about 1V.



With many cells the discharge current is reduce to about 0.2A and the charger may discharge down to 0.7V or lower.
It will first switch to charging When all batteries are empty.



M1: 39.6°C, M2: 36.6°C, M3: 36.7°C, M4: 34.7°C, M5: 37.2°C, HS1: 47.7°C
The heat is distributed over the full length of the charger and it is acceptable.


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



Conclusion

This charger is fairly good at charging many AA batteries, I could have wished for faster termination and lower (or none) trickle charge. The cycle/discharge function is not that good, because it over discharges some batteries when doing multiple batteries at a time.




Notes

The charger was supplied by Banggood for review

Here is an explanation on how I did the above charge curves: How do I test a charger
Read more about how I test USB power supplies/charger