Charger Yi Fang EIZFAN WF4

DSC_8360

DSC_8365 DSC_8364

Yi Fang Technology is a company selling chargers and batteries branded EFAN and EIZFAN.

DSC_8358

The charger arrived in a cardboard box with the model number on it and not any other information.

DSC_8359

The box contained the charger, a power supply, a car adapter and a instruction manual in English and probably Chinese.

DSC_8368

The charger has a single 12V input for use with the power supply and car adapter.

DSC_8369

The user interface is a small display and a single button to select current.

DSC_8428

The display shows voltage with two decimal places and animated battery symbols when charging.
Like many other chargers it is missing a dedicated battery full indicator, you have to look at the animation. It will stop with all blocks in the battery shown, when the battery is full.

DSC_8374 DSC_8375

The slots uses the typical design with a slider. They are with metal rails, but the slider is locking up when pressed at an angle, like when putting batteries in.
The slots can accept batteries from 30.5 to 71.2 mm.

supportedBatteryTypes

supportedBatterySizes DSC_8411 DSC_8412 DSC_8413

DSC_8404 DSC_8405 DSC_8406 DSC_8407
DSC_8408 DSC_8409 DSC_8410

The charger can easily handle 70 mm long batteries including flat top cells.



Measurements


Charging LiIon

Efan%20WF4%200.25A%20(PA18650-31)%20%231

At 0.25A the charger does a nice CC/CV charging with about 50mA termination current.

Efan%20WF4%200.5A%20(PA18650-31)%20%231

At 0.5A the charger has the same nice CC/CV curve and the same 50mA termination.

Efan%20WF4%201A%20(PA18650-31)%20%231

And also at 1A.

Efan%20WF4%201A%20(PA18650-31)%20%232
Efan%20WF4%201A%20(PA18650-31)%20%233
Efan%20WF4%201A%20(PA18650-31)%20%234

The 3 other channel is charging fine.

Efan%20WF4%201A%20(BE18650-26)%20%231

Efan%20WF4%201A%20(PA18650-34)%20%231

No problem with 18650 batteries with other capacity.

Efan%20WF4%201A%20(AW16340-IMR)%20%231

The charger handles this old cell nicely, even at 1A.

Efan%20WF4%200.25A%20(AW16340-IMR)%20%231

A more realistic charge current for this old cell.

Efan%20WF4%200.5A%20(AW18350-IMR)%20%231
Efan%20WF4%200.5A%20(KP14500-08)%20%231

Two more normal small cells are charged fine.

Efan%20WF4%201A%20(4xPA18650-31)

Using all channels is no problem, there is full current for all cells.

Efan%20WF4%201A%2012V%20(4xPA18650-31)

The charger uses nearly 2A at 12 volt.

Temp1493

M1: 40,9C, M2: 44,3C, M3: 45,0C, M4: 40,5C, M5: 45,3C, M6: 42,1C, M7: 47,8C, HS1: 58,3C
As usual there is som hot parts inside the charger, the two center batteries do get fairly warm (To avoid this use 0.5A charge current).

StartupLiIon

The charger needs 5 seconds to initialize.

CurrentChangeLiIon

Current can be changed at any time during charge.



Charging NiMH

Efan%20WF4%200.25A%20(eneloop)%20%231

With 0.25A current the cell is charged fine and it terminates, there is no trickle charge.

Efan%20WF4%200.5A%20(eneloop)%20%231

With 0.5A current the termination looks like maximum voltage termination.

Efan%20WF4%201A%20(eneloop)%20%231

At 1A it is also a maximum voltage termination. I do miss a small temperature raise, showing that the cell is filled completely, i.e. it stops before the cell is full.

Efan%20WF4%201A%20(eneloop)%20%232
Efan%20WF4%201A%20(eneloop)%20%233
Efan%20WF4%201A%20(eneloop)%20%234

All channels look similar.

Efan%20WF4%201A%20(eneloopXX)%20%231

With the XX cell the temperature raise is present, i.e. the cell is filled.

Efan%20WF4%201A%20(powerex)%20%231

Same with the Powerex and here it looks like a -dv/dt termination.

Efan%20WF4%200.5A%20(eneloopAAA)%20%231

The AAA is terminated a bit early.

Efan%20WF4%201A%20full%20(eneloop)%20%231

The charger is fairly fast at detecting a full cell.

Efan%20WF4%201A%20(4xeneloop)

Four eneloops is no problem, here the termination is on voltage.

Efan%20WF4%201A%2012V%20(4xeneloop)

With an external power supply I can see the charger uses about 1A at 12V when charging.

Temp1507

M1: 44,4C, M2: 47,8C, M3: 52,8C, M4: 44,6C, M5: 44,5C, M6: 41,4C, M7: 42,9C, HS1: 69,1C
NiMH do get rather warm, especially the two in the middle. It can be avoided by using 0.5A charge current.

StartupNiMH

The charger only need 3.5 seconds to start a NiMH charger.

ChargeNiMH

The charger stops charging to measure NiMH voltage during charge. These pulses are also the reason for the pulsing input current.

CurrentChangeNiMH

Again the current change button can be used at any time.




LiIon & NiMH mixed charge

There is no problem charging one LiIon and one NiMH battery at the same time.

Efan%20WF4%201A%20(eneloop+3xPA18650-31)

Efan%20WF4%201A%20(PA18650-31+3xeneloop)



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



Conclusion

The charger has a good CC/CV charge curve for LiIon. With NiMH it uses a combination of voltage and -dv/dt, in my opinion the voltage termination is slightly to low and it would have been nice with a top-off charge after a voltage termination (This behaviour is very common for NiMH chargers).

The only real minus I have about the charger is the slider, everything else works fine.



Notes

The charger was supplied by Yi Fang 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 and chargers