Danae DUO 9000 (Sometimes it is also called MAHA)






This is a charger and usb power bank, it has space for two AA or AAA batteries and with a switch it can either charge them or be used as a usb power bank.



The charger is delivered in a blister pack. In the last picture I have collected all the markings, if anybody wants to read it.



The package included the charger, mains power supply, car power adapter, usb power adapter and a usb charge cable for something.



On the back the charger has a very thin barrel (ø2.35mm)connector for DC input, either 5 volt ot 12 volt can be used. It can be used for the mains adapter, car adapter and usb adapter. The usb output is also located here.



On the side is a 3 position switch: usb output, off, charge.



There is two leds, one for each battery, they are used while charging:
Red=charging.
Flashing red=Error or full battery
Green=charging done



The slots are the common two positions for AA and AAA batteries.







Measurements

• When charger is selected, but no input power connected it will draw 0.3mA from the battery.
• Charger will detect at battery at about 0.3 volt and start charging.
• Led will light steady red during charge and flash on errros.
• When charge is finished the led will change to green.
• Charging on a full battery will show error, not green.

Charging NiMH



The charger uses a bit below 400mA charge current. It looks like it terminates on voltage, but there is a small temperature increase, i.e. the battery is full. The charging time is fairly long at 5.5 hours.



On the second slot it does not look like it erminated, but more like a timeout after 7.5 hours.



With the eneloop pro is is a bit difficult to see if termination is due to timeout or due to a real termination.



The XX are terminated on a timeout.



With the powerex it might be a real termination or timeout.



For the AAA it looks like a timeout after 2 hours 35 minutes.



Starting with full batteries the charger do stop, but with an error indication.



Again termination on timeout.




The charger will work with both 5V and 12V input and in both cases the terminations is on timeout.



M1: 41,0°C, M2: 39,5°C, M3: 31,3°C, HS1: 43,1°C
The charger generates a lot of heat for the low charge current.
Note: Thermo test is done with the supplied 12V power adapter as power supply.



M1: 45,1°C, M2: 45,0°C, M3: 39,7°C, HS1: 56,9°C
A quick opening of the lid shows the battery temperature.



M1: 41,7°C, M2: 42,7°C, M3: 39,5°C, HS1: 55,2°C
The batteries are slightly cooler if I am charging with the lid open.



The charger is fairly fast to start. The voltage checks are used to terminate the charge with error if the voltage gets to high.



The charger current is the same with two cells.



USB output

• Usb output is coded as Apple 2.1A, this is wrong for 0.35A output.
• When usb output is not loaded it will draw 3mA from the batteries
• Usb output requires only one battery to work.

The usb output cannot deliver much current. The maximum is about 0.35A or 350mA.



Using two batteries does not really change it.



The usb output has an efficiency about 55%, this is resonable for the low input voltage.



I did my test with 0.25A output and with eneloop it could maintain the output for about 2½ hour.
Note: The efficiency if wrong because I only measure current for one cell and assume same current draw for both cells.



With two pro cell I got longer runtime
Note: The efficiency if wrong because I only measure current for one cell and assume same current draw for both cells.





There is a lot of noise in the output, even at this low current: 250 mVrms and 4.4 Vpp (Some of the spikes are more than 2 volt).


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




Conclusion

This charger uses a fixed time when charging, when it stops premature it will show an error. This is not a very good charging algorithm for LSD cells and the current is also too high to be useable for old style NiMH cells.
The manual warns agains using this usb power bank with a smart phone and as can be seen the current is way too low for that.

This is neither a greate charger nor usb power bank because the charger terminates on time and lots of noise in the weak usb output.
I cannot recommend it.



Notes

I found this device on Ebay from buykingkorea_seoul

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

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 and chargers