# Ultrafire Charger WF-139 questions



## flashlight nut (Jul 31, 2010)

Need a little advice here. This is my first venture into 18650 rechargables. I purchased the ultrafire charger and 2 ultrafire 3.7 protected batteries from Battery Junction, so all are brand new.
I guess a should have researched this particular charger on this forum first but I am stuck with my purchase. The charger does not come with instructions so I have a couple of questions.
- The led lights on the charger are red when charging but flash green every second or so. Is this normal?
- How long does it take to fully charge the batteries?
- Can I leave the batteries charging over night without worring about the house burning down?
Sorry for the lack of basic knowledge but new to the flashlight world.
Thanks in advance for the help.

Paul


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## king2penn (Jul 31, 2010)

flashlight nut said:


> Need a little advice here. This is my first venture into 18650 rechargables. I purchased the ultrafire charger and 2 ultrafire 3.7 protected batteries from Battery Junction, so all are brand new.
> I guess a should have researched this particular charger on this forum first but I am stuck with my purchase. The charger does not come with instructions so I have a couple of questions.
> - The led lights on the charger are red when charging but flash green every second or so. Is this normal?
> - How long does it take to fully charge the batteries?
> ...



1) Im not quite sure whether mine flashes green but my red definitely flashes when charging, so it should be alright

2) Mine takes about 5-6 hours on a mostly discharged battery

3) Ultrafire chargers have a poor reputation, especially with some of my stock spoiling and all that. Yes but i have done that before


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## 45/70 (Jul 31, 2010)

flashlight nut said:


> I guess a should have researched this particular charger on this forum first



This is true, but everybody has to start somewhere. As king2penn said about their chargers, they're definitely not the best. This pretty much applies to everything else they offer, as well, including Li-Ion cells. They're pretty much "hit and miss", mostly "miss".



> - The led lights on the charger are red when charging but flash green every second or so. Is this normal?


Yes. This is the charger pausing to check the cell's voltage during charging. I might add that this is not an approved method to charge Li-Ion cells, but won't go into that here.



> - How long does it take to fully charge the batteries?


I think king2penn covered that close enough. Charging time depends on the state of charge (SOC) of the cell, it's potential full capacity, the age of the cell, and other factors.



> - Can I leave the batteries charging over night without worring about the house burning down?


*No!*
The charging of Li-Ion cells for flashlight/torch use, differs greatly from charging your laptop, or cellphone. Laptops and cellphones have charging circuits designed _specificall_y for the _exact_ battery installed in them. The cells we use in flashlights vary enormously between manufacturers, capacities, exact formulation used in the specific cell, and other cell specific anomalies that the designers of even the very best chargers cannot take into consideration when designing the charger. For this reason when charging Li-Ion cells for flashlight use, one should *NEVER* leave the operation unattended, regardless of the quality of the charger being used. An unfavorable incident is unlikely, but the risk is still too great to consider doing otherwise.



> Sorry for the lack of basic knowledge but new to the flashlight world.
> Thanks in advance for the help.


In addition to reading, reading, and then reading some more, I would suggest that you check out the "Threads of Interest" sticky at the top of this Forum, as well as the "Smoke And Fire" thread for relevant information, as to the proper use and care of Li-Ion battery cells. A lack of basic knowledge can get you into real trouble. It is important to know and understand the differences between Li-Ion cells and other chemistries to properly use and care for them safely.

Dave


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## badtziscool (Jul 31, 2010)

I wouldn't leave them charging overnight unsupervised. There are too many horror stories and too many youtube videos of exploding li-ion batteries that it's just not worth the risk. Overcharging is a REAL danger.

Mine take about 5-6 hrs on a mostly discharged 18650 as well. But you can actually calculate approximate charge time based on battery capacity and the charge output of the charger, which 450mA. So for a 2600mAh battery, do 2600/450 = 5.78hours. That'll give you a ballpark figure of how long it'll take to charge that particular battery.

The charger led will flash green and then go back to red when charging. When it flashes green, what it's actually doing is stopping the charge process and measuring the voltage of the battery to see if it's at charge capacity and then resumes charge if it's not. That limit should be 4.2v but some chargers voltage measurements are kind of off so some will charge a little over 4.2 (not too good for battery life) and some will charge a little under.


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## kramer5150 (Jul 31, 2010)

*- The led lights on the charger are red when charging but flash green every second or so. Is this normal?*
Yes... provided they stop flashing at 4.2V and turn solid green.
*
- How long does it take to fully charge the batteries?*
~1-5-2 hours tops for me... but then again I never fully deplete my cells.

*
- Can I leave the batteries charging over night without worring about the house burning down?*
NO... absolutely NO... NO repeated again for emphacis. While I have done this before (3-4 times on accident), its best not make it a habit.

*
Sorry for the lack of basic knowledge but new to the flashlight world.
Thanks in advance for the help.*
Sure no prob.


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## jacknife (Jul 31, 2010)

If you go to-- lighthound ,,--Google-- LIGHTHOUND-----and go to batteries and carriers.. you will see sub titles --------click battery chargers ----------and the trustfire 139 is there.... and if you look around there- you will see( download manual). I just did it to be sure ..I have the same 139 ---- Its there go get it.. I checked for you.


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## jacknife (Jul 31, 2010)

If you dont find it let me know and I will Walk you through it, Mine also did not come with instructions, but LIGHTHOUND told me when I called them that The instructions,,,were on their site . so there I went... I did have to look around a bit to find it,,,, so I went back again now,, to do it again for you. Its there good luck..


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## old4570 (Jul 31, 2010)

Hmmmm. 

Older revision of the WF-139 or a later one ? 
Later ones stop charging , no trickle charge . 

The issue is the way the charger charges , as to whether this is an issue or not ? I dont believe has been established . 

Blaming the charger for damaging or shortening the lives of what may have been bad cells to begin with ? 

A lot of the WF-139 stuff seem to be from the earlier models , mine is some 12 months old now , and I like it , it stops charging on completion , and I have not noticed any battery issues from using the WF-139 . 

So the only thing I can think of , is U just need to make sure you have a later model , and not left over stock from a earlier revision of the WF-139 , since its these earlier models that earned a bad rep .


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## sigsour (Jul 31, 2010)

How can you tell the old model from the new?


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## flashlight nut (Jul 31, 2010)

Thanks to all for the responses. As always, CPFers are top notch and always there to help. I will read the links suggested and go to Lighthound for the manual. And most important, NEVER leave the charger unattended.


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## Monocrom (Aug 1, 2010)

flashlight nut said:


> - Can I leave the batteries charging over night without worring about the house burning down?


 
*NO!*

The WF-139 is a basic, bare bones, charger. Reliability is spotty, at best. Often, it will continue to trickle charge the cells even when they are done. That's bad. It's the sort of charger that you you have to keep a constant eye on. (Key word being "constant.") 

That's what I always do with mine, and I must admit that my sample is one of the better WF-139 chargers out there. When I pull the cells, they are hot. I always put them aside for 2 hours before using them. My Ultrafire charger is now a back-up one. The only charger out there that is worse is the DSD model. 

If you plan on charging your cells very often, just spend the extra money on a quality charger, such as the Pila IBC model. If you're like me, and don't use rechargeable cells often; the WF-139 will get the job done. But just be sure not to let it out of your sight.

I did experience the blinking green light on my sample as well. It means your cells are not charging properly. Check to be sure the charger is properly plugged in. If the same thing keeps happening, it might mean your cells are crap. That's what happened to me. I replaced the cells with those from a better brand, and the blinking green light stopped. My charger has worked normally since then. Red, when the cells are tossed on. Follwed by green, when they are fully charged. Then again, blinking green might mean there's something wrong with the charger itself. In my case, it was an issue with the cells.


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## entoptics (Aug 1, 2010)

Mine works fine. I've left it overnight, and on a few occassions, several days.

I know it's not smart, but so far, no worries. Cells are NEVER hot, and at worst, barely warm while the light is red. When the light goes green and I pull them out, they are at room temp.

Never measured a fresh off the toaster cell above 4.2 volts. I only use *protected* TrustFire, UltraFire, and Tenergy cells though.

EDIT: This may be naive, but an awful lot of VERY respected venders mentioned on CPF seem to be selling these horrible death traps. It seems to me that they may have more hard data than the average CPFer, and I don't consider their products to be quite as lethal as web rumor/anecdote seem to believe.

That being said, lots of "reputable" products have resulted in serious incidents due to deception/ignorance (Toyota, Firestone, Philip Morris, BP, etc)


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## Albinoni (Aug 1, 2010)

badtziscool said:


> I wouldn't leave them charging overnight unsupervised. There are too many horror stories and too many youtube videos of exploding li-ion batteries that it's just not worth the risk. Overcharging is a REAL danger.
> 
> Mine take about 5-6 hrs on a mostly discharged 18650 as well. But you can actually calculate approximate charge time based on battery capacity and the charge output of the charger, which 450mA. So for a 2600mAh battery, do 2600/450 = 5.78hours. That'll give you a ballpark figure of how long it'll take to charge that particular battery.
> 
> The charger led will flash green and then go back to red when charging. When it flashes green, what it's actually doing is stopping the charge process and measuring the voltage of the battery to see if it's at charge capacity and then resumes charge if it's not. That limit should be 4.2v but some chargers voltage measurements are kind of off so some will charge a little over 4.2 (not too good for battery life) and some will charge a little under.



My question here is like with most chargers when the batt is fully charged and the charger sensors it, doesnt it simply cut off so the batts dont heat up and overcharge ?


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## qandeel (Aug 1, 2010)

now this is somehow cofusing . we are hearing 2 different messages here about the charger blinking green while charging. Some say it is normal and others say there is something wrong.

Can somebody kindly help to remove the confusion 

Thank you all for the good info


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## pae77 (Aug 1, 2010)

There are several different versions of the WF-139 and each version behaves somewhat differently so depending on which version a person has, they describe a different behavior and opinion as to how good the charger is. I don't have any of them but from what I have read, the most recent version is quite decent (in contrast to the earlier versions which didn't fully terminate and frequently tended to overcharge) and as pointed out by Oldxx above, the most recent version cuts off the power when the batteries are fully charged unlike the earlier versions.


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## old4570 (Aug 1, 2010)

qandeel said:


> now this is somehow cofusing . we are hearing 2 different messages here about the charger blinking green while charging. Some say it is normal and others say there is something wrong.
> 
> Can somebody kindly help to remove the confusion
> 
> ...


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## kramer5150 (Aug 1, 2010)

FWIW... both of my WF-139 chargers are ~2 years old at least. I bought them from DX, about a year apart.

-Unloaded the LED is green
-Load cell, LED turns red and blinks green
-Blinks once every ~second
-LED turns solid green when charge reaches ~4.18V
-Charge terminates at at that time and there is no trickle charge current

I do not know how it behaves with protected cells, I only have unprotected cells.


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## acbezzi (Aug 26, 2010)

i have just reveived my wf139 and UF protected batteries from DX. i've already ordered a voltimeter but it hasn't arrived yet so i cant say the state of my brand new batteries. i just put them to charge, but my charger DOES NOT FLASH GREEN. it flashes only RED. i saw everybody saying it should flash red and green. is it ok?


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## Monocrom (Aug 26, 2010)

acbezzi said:


> i have just reveived my wf139 and UF protected batteries from DX. i've already ordered a voltimeter but it hasn't arrived yet so i cant say the state of my brand new batteries. i just put them to charge, but my charger DOES NOT FLASH GREEN. it flashes only RED. i saw everybody saying it should flash red and green. is it ok?


 
Most likely your charger is fine, but your batteries are crap.

Learned that myself, the hard way. Sometimes Ultrafire cells don't work properly with the Ultrafire WF-139 charger. My AW brand cells work just fine with my Ultrafire charger. I encountered the same problem you did with my first batch of Ultrafire cells. Switched over to using AW cells, and no more problems.


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## qazx (Sep 2, 2010)

acbezzi said:


> i have just reveived my wf139 and UF protected batteries from DX. i've already ordered a voltimeter but it hasn't arrived yet so i cant say the state of my brand new batteries. i just put them to charge, but my charger DOES NOT FLASH GREEN. it flashes only RED. i saw everybody saying it should flash red and green. is it ok?




ive just brought the wf139, mine does the same with aw 18650 cells, flashes red when charging then solid green when finished. i think this is normal. perhaps ultrafire have changed it on the new models to not do the green and red flash


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## GunnarGG (Sep 2, 2010)

I have the WF-138 that I use for my AW RCR123 and it seems to work fine. When it charges it's red with green blinks about every second and then constant green when fully charged. I measure my batteries after charge and they are always at 4.21 V fresh out of charger.
I guess it works in the same way as the WF-139 so this talk about about quality/safety worries me a little bit.

I have been thinking about getting some 18650/17670 batteries and then I also need a new charger.
At 4Sevens they sell the Cytac 139 that they say is an upgrade to the WF139.
Anybody that has any experience from that charger? Would that be a better choice or is it about the same?


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## 45/70 (Sep 2, 2010)

GunnarGG said:


> ......I guess it works in the same way as the WF-139 so this talk about about quality/safety worries me a little bit.



Hi GunnarGG, if you haven't already, you might want to check out mdocod's thread. I don't believe the WF-138 is covered, but the WF/UF 139 is, among many others. The 139 has been upgraded since the one he tested, and has been improved somewhat, however there is some discussion as to just exactly how much better it actually is. The Cytac 139 is tested. Personally, I'd pass on both. I do use a WF-138, mostly for charging LiFePO4 cells though.

Dave


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## jirik_cz (Sep 2, 2010)

acbezzi said:


> i have just reveived my wf139 and UF protected batteries from DX. i just put them to charge, but my charger DOES NOT FLASH GREEN. it flashes only RED. i saw everybody saying it should flash red and green. is it ok?



There are at least two or three versions of WF-139 charger. The original does flash green so you probably has a copy. I know that some fake wf-139 might explode when powered with 230VAC here in Europe.


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## 45/70 (Sep 2, 2010)

jirik_cz said:


> There are at least two or three versions of WF-139 charger. The original does flash green so you probably has a copy. I know that some fake wf-139 might explode when powered with 230VAC here in Europe.



I keep hearing rumors about "fake" UltraFire products. I think it's more likely that UltraFire just sources from different suppliers often. The idea of imitating/copying an already poor line of products just doesn't make sense. As someone already pointed out in another thread, a faked UltraFire product would likely be better than the "real" one.

Dave


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## jirik_cz (Sep 2, 2010)

I know that it is hard to believe that Ultrafire can make something good and reliable, but if you buy WF-139 from AW, you will always get the right one. Fake versions usually come from DX and are cheaper.


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## Font size (Aug 30, 2012)

AW told me to buy from Lighthound because they have better shipping within the United States. I am sure this is the right charger for AW cells. I have used my UltraFire Rapid Charger for 3.7 Lithium batteries for many years without any problems at all. It works like you expect any charger to work, same as the Energizer I got from the grocery store for normal cells. When the Ultra charges it's red with green blinks about every second, and then constant green when fully charged. As far as I can tell it does not overcharge or need any special care whatsoever.


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## Monocrom (Aug 31, 2012)

Which WF-139 do you have? They range in quality from **** poor all the up to barely decent. Sounds like you got one of the better ones.

As mentioned two years ago, this is a basic charger at best. Other members have reported issues with trickle-charging. For those who ended up with one of the **** poor ones, special care is indeed needed. Don't let the batteries charge overnight. And, pull them as soon as the light turns green. Which means keeping a constant eye on the charger.


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## Shadowww (Aug 31, 2012)

What's the point of buying $15 WF-139, when Xtar WP2 II is just 3 bucks more, and better in every possible way? *shrug*


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## Sharpy_swe (Nov 3, 2012)

Is the charging time the same for two batteries as one?


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## roadkill1109 (Nov 3, 2012)

Sharpy_swe said:


> Is the charging time the same for two batteries as one?



If the charger has independent charging channels, then yes, if not, the charging capacity is shared by both cells causing charging times to double, if not, a bit longer than just charging one at a time.


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## Sharpy_swe (Nov 4, 2012)

roadkill1109 said:


> If the charger has independent charging channels, then yes, if not, the charging capacity is shared by both cells causing charging times to double, if not, a bit longer than just charging one at a time.



Ok, thanks


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## sween1911 (May 16, 2013)

I just bought a WF-139 from Lighthound with 2 Protected AW17500's to run in a Surefire Z3 w/ Malkoff M60. This is my first foray into Rechargeable Li-Ions. I got my meter all ready to check cells.


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## martosound (May 14, 2016)

HI everybody,

I have an Ultrafire Charger WF-139 from 5 years. I'm charging old 18650 type batteries from laptops. The cells are unprotected. I haven't any problems. Charger works well. :laughing:


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