Test/Review of Charger Yi Fang EIZFAN WF4

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HKJ
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Test/Review of Charger Yi Fang EIZFAN WF4
Charger Yi Fang EIZFAN WF4

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

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

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

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

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

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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

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



Measurements
  • When not connected to power it will drain about 0.2mA from batteries.
  • Voltmeter is within 0.03V.
  • The voltmeter can show voltage below 0.3 volt, but will not be started before the voltage has been above 0.5 volt.
  • The voltmeter will show up to 4.23 volt and will be turned off if voltage is above about 4.3 volt.
  • The charger will charge with 0.8mA from 0 volt and not report any battery.
  • At 0.5 volt regular charge current will be applied and show the charge animation.
  • Above 2 volt the charger assumes LiIon.
  • Charger always starts with the 0.25A setting.
  • When charge is finished the charger will charge with 0.1mA.
  • Charger will restart if voltage drops to 3.9 volt
  • Charger will restart charging after power loss, or battery insertion.
  • The charger has a buzzer with low volume that will sound when charging is done.
  • Specifications on charger says 4.2V +/-0.02V (Usual it is +/-0.05V).


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: 40,9°C, M2: 44,3°C, M3: 45,0°C, M4: 40,5°C, M5: 45,3°C, M6: 42,1°C, M7: 47,8°C, HS1: 58,3°C
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.

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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.

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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: 44,4°C, M2: 47,8°C, M3: 52,8°C, M4: 44,6°C, M5: 44,5°C, M6: 41,4°C, M7: 42,9°C, HS1: 69,1°C
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

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Edited by: sb56637 on 06/25/2015 - 14:21
HansWursT619
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Although i have never heard of this company, the review sounds very positive.
Is this charger a valid alternative for the Nitecore i2/i4? This reviews sounds quite a bit more positive.

But for the nitecore we have longtime experiences and i seems to hold up pretty good over several years.

P.S. I love you website, but its a bit overwhelming. How about adding a “recommended” section for the several categories like charger and batteries. With recommended charger under 20$ and above. And a recommended batterie per size?

HKJ
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HansWursT619 wrote:
Although i have never heard of this company, the review sounds very positive. Is this charger a valid alternative for the Nitecore i2/i4? This reviews sounds quite a bit more positive. But for the nitecore we have longtime experiences and i seems to hold up pretty good over several years.

The problems with the slider is very frustrating with this charger and as you says: There is no long time experience with this charger.

HansWursT619 wrote:
P.S. I love you website, but its a bit overwhelming. How about adding a "recommended" section for the several categories like charger and batteries. With recommended charger under 20$ and above. And a recommended batterie per size?

What charger to recommend depends on the requirements for the user. I do sometimes make recommendations on emails, usual it is Xtar and Nitecore.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

TheBo
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It seems to me that the curves are slightly better than in the i4? At least on Li-ions, Or am I wrong?

Rufusbduck wrote:
Getting discouraged is normal but doesn't finish the job.
garrybunk
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Thanks HKJ!  Anyone know what the going price is for one and where it's sold?  Also, does it do 1A to each of the 4 channels at the same time? 

-Garry

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HKJ
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garrybunk wrote:
Also, does it do 1A to each of the 4 channels at the same time?

Look at the curve where I specify (4x___), it is still 1A current.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

garrybunk
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Ah, I see.  Thanks!

-Garry

My Bike Lights Thread, Optics (TIR) Comparison Beamshots, Diffusion Techniques

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Photons Away
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The price on one site is €27.90 including VAT.

chi2
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Hi,
I’m wondering if the WF4 is capable of charging batteries of different capacities at the same time. If so, how is it possible to choose a suitable current? Sorry if this is clear to everyone else but I couldn’t find any info on this in the review and there seems to be no pdf version of the manual available online.
Thanks, Urs

HKJ
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chi2 wrote:
Hi, I'm wondering if the WF4 is capable of charging batteries of different capacities at the same time. If so, how is it possible to choose a suitable current? Sorry if this is clear to everyone else but I couldn't find any info on this in the review and there seems to be no pdf version of the manual available online. Thanks, Urs

You can always change different capacities at the same time, but you must select low enough current that it can be used for all batteries.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

chi2
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Thanks for the fast reply. This is quite a limitation.

HKJ
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chi2 wrote:
Thanks for the fast reply. This is quite a limitation.

That depends on what you use for batteries and when you charge.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

chi2
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Oh and I forgot: Thank you for this great review and all the other ones! Your work is valuable to so many folks here and in other places and it is highly appreciated!

chi2
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I have received the WF4 a week ago and while it charges batteries just fine, the problem with the locking up sliders is more annoying than I would have thought it to be.

With short batteries like 18350 it’s less of a problem than with protected 18650 ones. Not only is there no chance to put them in one-handed, it’s even a problem with both hands, especially with the last of four batteries as in this case there is no more space left for a finger to block the slider in its outmost position

I don’t know if the developpers have ever tried to actually put in four 18650 on their own :X.

Has anyone found a solution to this? Would you rather apply WD40 or silicone grease – or something else?

Thanks in advance, Urs

chi2
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Tried silicone spray and got quite good results. Still, I went for an X4 which has much better sliders and 2*2A. Happy with that one.

colliedoggy
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This charger available in the UK under the name Foxnovo looks to be the same:

http://www.amazon.co.uk/Foxnovo-Capacity-Intelligent-Rechargeable-Batter...

MountainKing
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Thanks once again man. Looks like a good multi cell charger. I am nevertheless waiting on the new multi cell charger review by HKJ from XTAR.

Never ever forget and forgive. Niwal**er new kid on the block trying to act tough.
http://budgetlightforum.com/node/24847
Do not support this brand.

DINODIRECTSCAM COMPANY. DO NOT BUY
http://budgetlightforum.com/node/11324?page=2#comment-254983