WF-139 charger

[Ozgeardo]

Ok my learned friends, I am still on a big learning curve with all things illuminating, I have been using a WF-139 charger for well over a year or more with no problems. I keep reading that there have been problems for some users with this unit so I have been subjecting mine to all sorts of abuse and various tasks of late in an effort to destroy it and give me an excuse to buy a better charger but I just can not kill this animal nor any of my batteries (various inc AW & Ultrafires).

I have deliberately run down several RCR123's and 18650's to near zero voltage yet my WF-139 always kicks in and starts charging bringing the batts upto correct voltage every time!

So me thinks (in my non technical way) that perhaps as we "down under" run of 240 volts mains and not 110 volts that the charger perhaps is working more efficiently ? I have no idea but could this be an issue ?

Often I have left batts on charge for extended periods (tasked away to other jobs and forgot, naughty me) left a pair of 18650's on charge for 3 days (oops :devil: ) but no problems experienced.

I have also charged from 12 volts but have noticed that overdischarged batts need a couple of tickles (power off/on) to get charging but generally no probs on 12 volt either.

Have I just been lucky? I have several colleauges/work stations whom I am about to puchase and supply a couple of these chargers to.

Any thoughts...............

 

[DM51]

This belongs in the Batteries section. Moving it there...

 

[xenonk]

I have deliberately run down several RCR123's and 18650's to near zero voltage yet my WF-139 always kicks in and starts charging bringing the batts upto correct voltage every time!

You're killing your batteries and not the charger. Though once one of those fails in a big way, you might get your charger destruction.

 

[1 what]

I've had no problems with my WF-139 and found its auto cut-off works fine. I must admit that I use my Pila if I have to put cells on charge when I'm not home (they are charged in an area where they cant start a fire).

 

[Ozgeardo]

This belongs in the Batteries section. Moving it there...

Sorry, I will plead "newbie" in my defence

You're killing your batteries and not the charger. Though once one of those fails in a big way, you might get your charger destruction

Yes xenonk, you are probably correct that is why I used some batts that I intend on replacing, some RCR123's that have been used enough times to warrant their replacement (many hundreds of charges) and some Ultrafires that I consider "expendable" and some AW 18650 (2200) that I intend on replacing with the new 2600's.

1 what, I agree that any charger should be left in a safe place where fire will not be an issue no matter how safe you consider it to be. All my chargers live on a metal bench top and have 2 safety trips on the power supply.

Can anyone throw any light on the 240 volt v 110 volt theory of mine?
Has anyone on 240 volt had any issues?

 

[DM51]

Sorry, I will plead "newbie" in my defence

A good defense, too. The different sub-forums can be a little confusing for a while, until you learn what belongs where.

 

[tresurehunt]

when i put my 18650 cells into the wf-139 charger they flash red/green,
after a few seconds it goes full green,does this mean they are fully charged ?
when i test them in my jetbeam lll m it doesnt light up at all ?

 

[elwood]

You're running them down to 0 volts? If you're using protected (for your sake I hope you are) then running them till they read 0 volts means that you activated the protection circuit. Li-ion batteries are considered "empty" at around 3.2 or 3.4v's. You should not be discharging them so much that the protection circuit kicks in. You're severely lowering the lifespan of the battery and you could potentially run into some serious problems if the protection circuit doesn't kick in and you actually do overdischarge them. When you go to recharge them they might go

I've only been a flashaholic for a few months but that's what I've gathered thus far. I'm sure, and hope, you will get others who will respond with way more knowledge on the subject than me.

Read this and most of the threads here.

 

[Metatron]

i use that particular charger sometimes and only yesterday decided to check what its doing, the green comes on at 4.25 volts and the batt fresh off the charger measures 4.18 volts, so im pretty chuffed

 

[tolkaze]

I use 240v here, and have also used 240 and 110v with an inverter (in the car)... the charger acts the same with all three power supplies except, it might be getting slightly warmer (charger, not the batteries) with 240v mains... but that could be because of charging location or anything. Batteries always come off at about 4.25 and settle to 4.18 to 4.19

 

[KD7EIR]

I don't think that the mains voltage has anything to do with it. Some of these chargers are junk and some of them work just fine. You got one of the good ones.

 

[palomino77]

Glad to hear that most of the WF-139 chargers work fine. The ones that don't, as far as I know, are fakes bought at DX and not US dealers or other reputable sources. I'm glad because these are easy to come by, and we have other options beside Pila. I think they are improving every day, maybe some day soon we will have a Pila quality at a much more affordable price and more places where to buy from.

 

[Superdave]

never had a problem with mine

 

[digitor]

So me thinks (in my non technical way) that perhaps as we "down under" run of 240 volts mains and not 110 volts that the charger perhaps is working more efficiently ? I have no idea but could this be an issue ?

I don't think this would make any difference to the charging performance - the WF-139 internal switcher converts 100-240VAC to 12VDC, so the charger electronics always see the same voltage.

Cheers

 

[KiwiMark]

I have 2 WF-139 chargers - both work perfectly fine.

 

[DM51]

The WF-139 is an OK entry-level charger. HOWEVER, users must understand:

1. The charging algorithm is "whack it up and then let it settle back", rather than the correct CC-CV method. This gives a temporary overcharge to ~4.25-4.30V, which then usually settles back in a rather hit-and-miss way to ~4.2V

2. This is NOT the best way to get maximum cycle life out of your cells

3. It relies on a cell's protection circuit to terminate the charge, so:

4. Do NOT use it with unprotected cells

5. There have been numerous copies and clones of the WF-139 over months and years, all performing in much the same way, but some units have caused problems that have been documented here on CPF. If you are going to get a WF-139, make sure it is from a reputable source.

6. The Pila IBC charge costs ~2x as much, but it is a far superior unit which will in the long run be better for your cells.

 

[hoffmand]

So is DX considered a "reputable" source? I'm not sure if it's worth paying 50% extra to get the same charger from AW or 47's.

The Pila is 4x more than the WF-139 from DX. If I was charging batteries every day it would make sense, but I don't, so it doesn't.

 

[Kato]

I use AW lithium ion cells in all my duty lights, so I top them off on my WF-139 once or twice per week depending on usage.

Thanks to this thread, I just ordered a Pila IBC.

 

[45/70]

So is DX considered a "reputable" source? I'm not sure if it's worth paying 50% extra to get the same charger from AW or 47's.

I buy certain items from DX, including a couple chargers, never a WF-139 though. The thing about AW, is customer service. If something is wrong, he fixes it "right now". It would seem that he "screens" his products a bit better as well.

The Pila is 4x more than the WF-139 from DX. If I was charging batteries every day it would make sense, but I don't, so it doesn't.

As for a good charger vs. a WF-139, would you consider your batteries lasting 4x longer a good trade off? I'm not saying one way or the other, in your situation, that's just how I'd look at it.

Dave

 

[KiwiMark]

I have 2 of the WF-139 chargers and I am pretty happy with how they work.
Speaking ONLY about WF-139 chargers that are working as they should:
They ARE a little harder on the batteries, but I am not convinced that they will kill your Li-ions significantly faster than other chargers. Mine don't trip the Li-ions protection circuit - they simply charge at a constant current until the resting voltage of the cell = 4.2V. This means that the voltage under a charging current will go ABOVE 4.2V for a short time. The cell will end up with the same charge state and 4.2V condition at the end of the charge as you would get from a Pila CC/CV charger - but the Pila will taper off the charge amperage so that the voltage while under a charging current will not exceed 4.2V, the WF-139 does NOT do that!

I have checked an 18650 cell during charge with both the amps monitored with a multimeter and the volts monitored by another multimeter. The amps never changed and the volts went up to 4.28V, but the resting volts when the charger turned off was exactly 4.2V as soon as the charger turned off. It seems that the WF-139 has very quick pauses in the charging current when it measures the volts, if the 'no load' voltage is under the 4.2V then it keeps on charging.

Because the ending charge state of the Li-ion seems to be EXACTLY the same as from a charger that uses the proper charging algorithm and the cell is only over 4.2V for a short time - I just don't see it as being overly harmful to the cell. But it is quite possibly a little harmful to the cell (otherwise why would everyone else use the CC/CV charging method). So far I have been unable to find any information about how much damage is done by the CC charging method - so I can't quantify the amount of damage, so it is hard to say how consequential it is (or isn't).

Now mostly I am using 2 hobby chargers that let me select the charging current and use the proper CC/CV algorithm - they also let me log the data to a PC for analysis and can discharge & cycle batteries if I want. But I'll use my 2 WF-139 as I feel like and not worry TOO much about any harm to my batteries until someone can produce evidence that the harm is more significant than I currently believe it is.

But having said all that:
I can't see anyone regretting buying a good quality charger like the Pila, and the peace of mind benefit may make such a charger a great bargain!