Charger PSPower NT2000





This charger is a NiMH analyzing charger, it also has a usb power output.






I got the charger in a cardboard box with specifications on.



The pack included the charger and a power supply, the manual was not ready yet.



The charger has a 12V input for the power supply and a usb output.



The charger has two buttons and a lcd display to show functions and charge status.
The SLOT button is mislabeled, it is used as a current select button and as a display select button.
The MODE button is used to select mode, it will always select for all channels. To activate it hold it down for a bit.



The display can show mA, mAh, volt and hour (mAh will change to Ah for larger values).




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 0.1mA on AA cells.
• Power consumption when idle is 1 watt
• Voltage display is within 0.03V
• Charge will restart charging after power loss, or battery insertion.

Charge

In charge mode the current must be selected between 200mA, 500mA, 700mA and 1000mA



The charging is terminated on voltage and has a trickle charge, but not a top-off charge.
Display shows 1706mAh in 1:42





It is the same on the other channels.
Display shows 1729mAh, 1681mAh, 1710mAh





It works the same on the high capacity cells, the eneloopXX is fairly old and voltage is jumping up and down with the pulsing.
Display shows 2.33Ah, 1996mAh, 2.34Ah




There is no problem terminating at low charge currents.
Display shows 1712mAH in 8:34 and 1694mAh om 3:23



The AAA cell is charged fine.
Display shows 616mAh in 1:13



As usual a voltage termination is fast at detecting a full cell.
Display shows 59mAh in 0:03



With four cells the charger gets warm, this is unavoidable with the small charger size and no fan.
Display shows 1686mAh, 1786mAh, 1740mAh and 1766mAh



The charger uses less than 1A from 12V when charging four cells.



M1: 48,1°C, M2: 51,1°C, M3: 49,9°C, M4: 43,8°C, M5: 43,5°C, HS1: 57,5°C



The charger is about 14 seconds to start, because it waits for the user to select current.



Current is regulated with a slow pwm, here at lowest setting.



And here at highest setting.



Trickle charge is also done with the pwm, but the pulses is down to 80ms, this gives a average current of about 40mA with 1A charge current.



Discharge

In discharge mode the current must be selected between 100mA, 250mA, 350mA and 500mA. The charge current will be twice the discharge current. The display will show charged capacity and time.



The charger discharges to 0.9 volt, then waits about 20 minutes before it recharges the battery.





The 3 other channels works the same way.
Display shows 1758mAh in 1:45, 1750mAh in 1:45 and 1741 in 1:44



Lowest discharge rate, this takes a long time with a AA cell, but works fine.
Display shows 1755mAh in 8:47



No problem discharging four cells at the same time.
Display shows: 1800mAh, 1813mAh, 1808mAh, 1757mAh



M1: 36,7°C, M2: 38,7°C, M3: 38,8°C, M4: 36,9°C, M5: 43,7°C, HS1: 44,4°C
It is easy to see that the discharge resistors are place in front of the charger, not below the batteries (good).




Discharge is controlled with pwm, here at lowest setting.



And at highest setting.


Discharge refresh

In discharge refresh mode the current must be selected between 100mA, 250mA, 350mA and 500mA. The capacity shown is the discharge capacity.



The refresh function will do 3 discharges (My first one was a bit fast because I stated with an empty battery).
Display shows 2,03Ah in 4:03


Charge test

In charge test mode the current must be selected between 200mA, 500mA, 700mA and 1000mA. The capacity shown is the discharge capacity.



This test will charge the battery, discharge it and charge again.
Display shows 2,04Ah in 4:04


Usb output

• Usb output is coded as Apple 2.1A, but the coding may be out of tolerance.

The usb output can deliver 1.1A, that is fine for a 1A rated output. The efficiency is rather low.



The output can deliver 1A for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.



HS1: 67,4°C



M1: 45,6°C, HS1: 66,7°C



Noise is 12mV rms and 111mVpp



Noise is 13mV rms and 133mVpp, this is very low noise.


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



Conclusion

The charger uses pwm and terminates on voltage as most battery analyzers do, but it is lacking a top-off charge to guarantee the batteries are full charged. At 1A charge current the trickle charge current is a bit high.
It looks like the capacity display is a bit low when charging and a bit high when discharging.

The usb output delivers 1A with very low noise, but the coding is not correct.

The analyzer is acceptable to keep track of NiMH batteries




Notes

The charger was supplied by Power Advanced Limited 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