Ultrafire WF-188 TEST !

I like the sliding contacts , they feel nice , I just wonder a little about the long term + there is no problems with any 18650 I can think of , they all will fit with room to spare [ Yes even the Xtar 18700 with room to spare ] .

The only issue I have is the design of the cradle , if you knock the charger the battery may very easily be dislodged , so just bear in mind the batteries are not held in place very securely .

Now the the charger has sliding tabs for adjusting charge current and voltage range , I really hated them with a passion , they just screamed cheap to me , so when I opened the charger for some pictures I was some what remiss in putting them back when closing the charger , Im much happier with the tabs removed , allowing me access to the switches directly .
The charge chord seems to be a euro plug equipped one , so might be something to bear in mind .


By old4570 at 2011-01-01


By old4570 at 2011-01-01


By old4570 at 2011-01-01

I will update as I complete the battery charging tests .

OK some charging info :

650mA setting =

18650 Battery @ 3.79v - 600mA charge current
18650 Battery @ 4.11v - 350/360mA charge current
18650 Battery @ 4,18v - 290/300mA charge current

300mA setting =

18650 Battery @ 3.79v - 300mA charge current
18650 Battery @ 4.11v - 300mA charge current
18650 Battery @ 4.18v - 290mA charge current

Ive been runing tests on the 650mA setting , and when the charger terminates , its @ 4.21v/4.22v and once the light goes green it actually stops charging , I could not measure a charge current on termination .

There does seem to be an issue though , early termination . For some reason some batteries are terminating @ 4.14v/4.15v whilst others go 4.21/4.22v , it does not appear to matter whether the cells are protected or not they may fully charge or not . I dont know if this charger has resistance sensing and terminates early because some cells may have more internal resistance as they approach full charge , or whether its an issue with the sliding terminal and the way it is set up with a rail type system [ see pictures ] . Anyhow , I will explore this when I have done the 300mA tests . If it turns out to be some sort of resistance sensing , then it can be used to sort out your good cells from the not so good ones , but if this were your only charger it could leave you with a lot of undercharged batteries .

Currently testing 300mA setting :

There is no joy with the 300mA charge setting , it looks like early termination at 4.11volts on both channels .
Im going to mod the charger now to eliminate the rail system as a possible cause of the early termination , so keep an eye out , also I will take a video with the amp meter connected .

Modified UF-WF188


By old4570 at 2011-01-01

Hopefully the pictures tell a thousand words .
I wanted to eliminate the rail as a source of problems with the termination voltage , so I did a mod to directly wire up the negative sliding post to eliminate any possible contact problems that may result in causing an early termination . I did the mod to both sides , so both sliding posts are now hard wired . I will re test to see what happens .

Did it help ? Thats a good question , it would seem some cells are stopping at 4.17v now rather than 4.14/4.15v , problem with testing chargers is you end up with a lot of charged cells and not many empty ones , slowing down the testing as you try to drain cells so you can charge them back up .

If your desperate for a charger that can handle larger batteries , then I would reluctantly say go for it , but dont expect a flash product , I think the folks that made this charger need to go back and do there home work , because near enough is not good enough . Im still testing , and it might take a while longer to get the full picture , reporting on the fly can be a little hit and miss , but knowing that people were interested , well .
Im currently re-testing to see what difference the mods make , and It will take a little while .

Its early day's : But looks like "BINGO"

Ive been testing on the 300mA setting , and the batteries are now coming of the charger @ 4.17 lowest and 4.21v Highest ..

I did two a moment ago and they came off @ 4.2 and 4.21 , this is a serious improvement over 4.11v ..

I want to do some more testing to see what voltages I get , but this is much more like it , this is more in line with the sort of results I get with the WF-139 , the Trustfire TR-001 .

Its early , but it looks like the rail method of powering the moving negative post is just causing problems , I want to charge some more batteries @ 650 and 300 to make sure the charger is behaving as it should , but it looks like I found the problem . But for now , some more tests

Thanks... looking forward to this thread.
So its a CC profile fixed at either 300 or 650ma?... and there is no CV profile?

good!

waiting for your results...

the 300mA setting may be Constant Current , as it looks like it tries to maintain the 300mA charge rate for as long as possible , Constant Voltage , it looks like it maintains a voltage of 0.04v over the battery voltage .

So if a cell is say 4.12v , the voltage will be 4.16v when on the charger , open voltage is 4.7v .. [ Currently on 300mA setting - so will retest @ 650mA ]

The charge method appears to be the same as with the WF-139 , I will take a video shortly .

OK actually there seems to be a bit of a pulse [ maybe as it checks the batt ] so it actually might be 4.16v then it will drop to 4.14v and than back up to 4.16v as it goes along . [ 300mA ]
@ 650mA setting with the batt @ 4.13v it seems to be pulsing 4.2v - 4.19v - 4.2v

Update : The day is drawing to a close , Ive run out of half charged cells and now need to drain them as I go .

So far = the 300mA setting to start with , the charger seems to maintain 300mA for most of the charge cycle , only problem is it seems to terminate at 4.11v [ before mod ] . This is ok for 10440 cells but not 18650's

650mA setting , the charger seems to terminate all over the place , 4.13v 4.14v 4.15v 4.16v 4.17v 4.18v 4.19v 4.21v 4.22v , in fact it seems to terminate everywhere but 4.2v oo:

One battery has been through 3 charge cycles in this charger , it terminated @ 4.14v 4.17v and 4.22v , its almost like termination voltage is a lottery .

My Wow18650 is in its 3rd cycle as I type this , 1st one terminated at 4.21v second one terminated at 4.17v and Im taking money on where it terminates next . My red Ultrafire 2600 Protected has been through two charge cycles , the first one it terminated at 4.17v and the second time 4.22v .

If you guys dont like the WF-139 , I dont know what your going to think about this one ? :thinking:

I think who ever came up with this charger , really needs to actually charge some cells with it before putting it on the market , I cant believe for a moment that this charger was fully tested

I think the search continues for a Good 18650 Li-ion charger , how hard can it be to make a charger terminate charging at 4.2v
At least some one should consider installing trim pots so that users can tune the charger themselves , id gladly pay an extra dollar for such a option .

I will continue testing , and if there is anything new to report , I will do so ASAP , but for now , I remain somewhat un-impressed .

Above impressions are for the stock charger : I am re-testing after doing mods :

Thank you for testing this charger.

To point out a possible "bright side" if there is one....

I'd rather own a charger that terminates ALL OVER THE PLACE between 4.12 and 4.22V than some of the other chargers I have tested, that will trickle and hold cells at 4.26V all day and all night.

old4570 said:

OK some charging info :

650mA setting =

18650 Battery @ 3.79v - 600mA charge current
18650 Battery @ 4.11v - 350/360mA charge current
18650 Battery @ 4,18v - 290/300mA charge current

300mA setting =

18650 Battery @ 3.79v - 300mA charge current
18650 Battery @ 4.11v - 300mA charge current
18650 Battery @ 4.18v - 290mA charge current

Click to expand...

Are these charging voltages or resting voltages?

----

We can learn a lot more about the charger if you take advantage of those long bays, and cram the multi-meter leads in there while it's charging, taking voltage measurements and seeing what happens.

I think it would be interesting to see what type of charge method is occurring there.

Eric

mdocod said:

Thank you for testing this charger.

To point out a possible "bright side" if there is one....

I'd rather own a charger that terminates ALL OVER THE PLACE between 4.12 and 4.22V than some of the other chargers I have tested, that will trickle and hold cells at 4.26V all day and all night.



Are these charging voltages or resting voltages?

----

We can learn a lot more about the charger if you take advantage of those long bays, and cram the multi-meter leads in there while it's charging, taking voltage measurements and seeing what happens.

I think it would be interesting to see what type of charge method is occurring there.

Eric

Click to expand...

Voltage is measured battery voltage : [ out of charger - so actual batt voltage ]
@ 300mA setting and charge voltage was 0.04v over batt voltage .
@ 650mA setting its higher , 0.07v over batt voltage

Charge method appears to be the same as the WF-139 , I will video tape the Multi meter when time permits , to see if it pulses like the WF-139 ..
There does appear to be a voltage pulse , which may be matched by a current pulse .

My WF-139 charges to 4.2v or a little less and then stops , does whats required , but people still po po it . Guess the later ones have to live down the earlier ones ...

Still not impressed with a charger that terminates like a lottery number picker , especially considering the WF-139 is as consistent as any charger you care to name .
This charger should have been in improvement , not a step backwards .

https://www.candlepowerforums.com/posts/3449038&postcount=2

Check out post 2 : Its late , time for bed , I will test some more tomorrow !

old4570 said:

I think the search continues for a Good 18650 Li-ion charger , how hard can it be to make a charger terminate charging at 4.2v

Click to expand...

If the Xtar WP6 charger lives up to it's specs, we might finally have the holy grail for low cost Li-Ion cradle chargers that actually charge properly (CC/CV).

Black Rose said:

If the Xtar WP6 charger lives up to it's specs, we might finally have the holy grail for low cost Li-Ion cradle chargers that actually charge properly (CC/CV).

Click to expand...

While it does look like an interesting charger, I still prefer my Tenergy Accucel-6, which is also about $30. Only thing is you need to make your own charging cradle.

Regarding the Ultrafire charger, it looks like a CC charger, but not a CC/CV charger. A proper CC/CV charger should slow the charging current down to about 50-100mA once the cell hits about 4.10v, and should continue charging at this rate till it reaches 4.20v.

On the 650mA setting it does ease of on the current , but it maintains 300mA almost to the end , so far Ive concentrated on the Termination voltage and now that it seems to be sorted I can start looking at other things .

But I like the fact that it maintains 300mA [ rather than 100mA or 50mA ] for as long as it does as it really speeds up the charge cycle , I really hate waiting 2 hours for the battery to be toped up .

Im just testing termination voltage a little more today to make sure its ok , then I will get a little more into the nity gritty , and I will try and chart the charge voltage and current .

jasonck08 said:

Regarding the Ultrafire charger, it looks like a CC charger, but not a CC/CV charger. A proper CC/CV charger should slow the charging current down to about 50-100mA once the cell hits about 4.10v, and should continue charging at this rate till it reaches 4.20v.

Click to expand...

Not exactly correct. A charger using a proper CC/CV algorithm will switch to CV, once the voltage of the circuit (cell inclusive) reaches 4.20 Volts, ending stage 1 (CC). During stage 2 (CV) the voltage will be maintained @ 4.20 Volts and the current will decline to no lower than 0.03C (where "C" equals the original charging current), at which point the charge will terminate. As such, there is no "proper" voltage to which a cell will be charged, using a proper CC/CV algorithm. The termination voltage is determined by the age, condition of the cell, and the charge rate used during charging. Older, well used cells charged at a fast rate will terminate at a lower voltage than newer cells in good condition charged at a slow rate etc.

It looks like the WF-188 is just another attempt at assembling inexpensive components that result in yet another inferior charger that kills older used cells by not using a proper algorithm, forcing cells to a ~4.20 Volt termination, regardless of their condition. It'll work, but why bother? :thinking:

Dave

The results are basically what I expected. The charger is similar to a WF-139 but with selectable voltage and charge current so no CC/CV. SheKor still seems the best cheap li-ion IMHO (I don't consider a hobby charger, Pila or the Xtar cheap) although no selectable voltage and charge current and you do need to fix the spring flaw if you want proper operation.

Of course some may prefer a charger with such a charging profile for high speed charging like old4570.

Nil Einne said:

The results are basically what I expected. The charger is similar to a WF-139 but with selectable voltage and charge current so no CC/CV. SheKor still seems the best cheap li-ion IMHO (I don't consider a hobby charger, Pila or the Xtar cheap) although no selectable voltage and charge current and you do need to fix the spring flaw if you want proper operation.

Of course some may prefer a charger with such a charging profile for high speed charging like old4570.

Click to expand...

I like more , my fav is the soshine 1A charger , though it does back off a lot more as it approaches 4.2 ..

And this charger does not force older cell to 4.2 ??? What would give anyone that idea ? , if anything this charger seems very sensitive to any resistance to charging , and terminates early ..

My older cells are terminating 4.15 4.17 , any cell with higher internal resistance , terminates before 4.2v

????? Quote 45/70
It looks like the WF-188 is just another attempt at assembling inexpensive components that result in yet another inferior charger that kills older used cells by not using a proper algorithm, forcing cells to a ~4.20 Volt termination, regardless of their condition. It'll work, but why bother?

Sorry bud , but what gave you this idea ?
This charger does anything but .

old4570 said:

Sorry bud , but what gave you this idea ?
This charger does anything but .

Click to expand...

Ive been runing tests on the 650mA setting , and when the charger terminates , its @ 4.21v/4.22v and once the light goes green it actually stops charging , I could not measure a charge current on termination .

Click to expand...

......For some reason some batteries are terminating @ 4.14v/4.15v whilst others go 4.21/4.22v.....

Click to expand...

Ive been testing on the 300mA setting , and the batteries are now coming of the charger @ 4.17 lowest and 4.21v Highest ..

Click to expand...

I did two a moment ago and they came off @ 4.2 and 4.21 , this is a serious improvement over 4.11v ..

Click to expand...

650mA setting , the charger seems to terminate all over the place , 4.13v 4.14v 4.15v 4.16v 4.17v 4.18v 4.19v 4.21v 4.22v , in fact it seems to terminate everywhere but 4.2v oo:

One battery has been through 3 charge cycles in this charger , it terminated @ 4.14v 4.17v and 4.22v

Click to expand...

My Wow18650 is in its 3rd cycle as I type this , 1st one terminated at 4.21v ......the first one it terminated at 4.17v and the second time 4.22v .

Click to expand...

Gosh, old, I really have no idea.

Seriously, I get what your saying about the WF-188 terminating all over the place. I do, really. My point though, is that this charger seems to at least attempt to, in some fashion, try anyway, to terminate the charge by voltage, of sorts.

As I pointed out in my last post, the charging circuit voltage, or the cell's OC voltage, either one, is not how termination of charge is determined when properly charging Li-Ion cells. The voltage of the cell has nothing to do with it. Termination of charge occurs when the charge rate drops to 3% (or 10% with most hobby chargers) of the CC charge rate during the CV stage when using a proper algorithm. Some how, I don't really get the impression that that is what this charger is doing, rather it would appear that it works similar to all their other chargers and just attempts to charge the cell to a certain voltage. This voltage figure has varied widely in the history of UltraFire chargers, as you are well aware of.

Dave

45/70 said:

Gosh, old, I really have no idea.

Seriously, I get what your saying about the WF-188 terminating all over the place. I do, really. My point though, is that this charger seems to at least attempt to, in some fashion, try anyway, to terminate the charge by voltage, of sorts.

As I pointed out in my last post, the charging circuit voltage, or the cell's OC voltage, either one, is not how termination of charge is determined when properly charging Li-Ion cells. The voltage of the cell has nothing to do with it. Termination of charge occurs when the charge rate drops to 3% (or 10% with most hobby chargers) of the CC charge rate during the CV stage when using a proper algorithm. Some how, I don't really get the impression that that is what this charger is doing, rather it would appear that it works similar to all their other chargers and just attempts to charge the cell to a certain voltage. This voltage figure has varied widely in the history of UltraFire chargers, as you are well aware of.

Dave

Click to expand...

Some of it was the rail used to transmit power to the sliding post .
But this charger does not charge to 4.21 or 4.22 every time .
It is the goal of chargers to charge to 4.2v , its what there designed to do .
This charger seems very sensitive to internal resistance , so if there is any resistance to charging this charger seems to terminate early .

Only time will tell , but so far , especially with older cells , they are not making it to 4,2v or higher , only a few good cells made it there ..
WOW18650 went 4.17v 4.21v and 4.22v
Fireworm Went 4.22v , one of my Xtar went 4.22v another went 4.21v ..
My older Trustfire Grey and Ultrafire grey all terminated around 4.15v to 4.17v , I had to put them in the Trusfire charger to bring them up to 4.2v .

Even my old generic Blue 18650's would stop around 4.18v and 4.17v , and they go 4.19v in the WF-139 and 4.2v in the Trustfire Charger .

My Soshine charger has not had much of a workout as yet , only charging some of my newer cells . [ What happens when you have a charger collection ]

I dont think this charger forces cells to 4.2v at all , in fact it might be the least likely charger in my collection to do so , thats capable of charging up to 4.22v .. My WF-139 can do 4.21v and my Trustfire can go up to 4.22v but only with cells that are very good .

I do believe this charger needs work , its not the best tool in the shed , as it comes stock , it may be a lottery as to termination voltage , my mod has solved this to some extent and it seems more stable and consistent now .
And I will say it once more , this charger seems very sensitive to any resistance to charging , and will terminate early with lesser quality or older cells .
Even putting the MM to the charger to measure voltage as its charging can cause termination , and did so several times .

I guess its my fault for posting information on the fly , and then answering peoples questions etc , + I played with the charger stock , and then modified it and posted such in the same thread ...
I might have to re-write the whole lot , as it takes more than one day to find things out .

And people tend to respond to different parts of the post , so information gets a little messy ...
Bu then its also a good way to hash things out , but I will see about re-writing the entire thing .
One of my Grey Ultrafire 2400mA batteries just terminated @ 4.19v , this is its 5th or 6th charge cycle and it terminated @ 4.13v when the charger was stock , after being moded , it terminated 4.15v , 4.17v 4.18v and this last one 4.19v , then they do say cycling Li-ions makes them better , this battery has been un used for at least 6 months or more .

OK old, I'm following you, and the reasoning behind why your coming to the conclusions that you are. I also understand the reason for your modding the charger.

old4570 said:

It is the goal of chargers to charge to 4.2v , its what there designed to do.

Click to expand...

But you see, this really isn't true, at least not exactly. The 4.20 Volt figure, found in Li-Ion cell white papers and wherever else it's referred to, is the "charging voltage", not the end OC voltage specification for a charged Li-Ion cell. This means that 4.20 Volts is the maximum voltage that the cell should be subjected to, when charging during the CV stage, or at any time the cell is on the charger, for that matter.

Any charger that subjects the cell to more than 4.20 Volts at any point during charging, could be considered as being out of specification, and not following the proper algorithm for the charging of LiCo (and, as far as I know, LiMn) Li-Ion cells. Of course, we're talking about an "ideal" situation here. There is some amount of tolerance allowed.

A charger such as the WF-139 (and it's looking like the WF-188, as well), which uses a CC algorithm and a "voltage check" to determine the SOC of the cell being charged, will effectively "force" the cell to a predetermined voltage, such as 4.20 Volts, regardless of the age, or condition of the cell, before terminating the charge. This is also the reason why these type chargers have a voltage potential higher than 4.20 Volts, as it is necessary to accomplish the task.

I think you are likely correct in assuming that the "rails" are the cause of the WF-188's erratic termination behavior. It seems to be acting more like a WF-139, with your mod. Anyone who is familiar with slide controls that utilize rails in audio equipment, knows how well they work.

So again, what we have with a voltage checking CC algorithm charger, is a charger which attempts to force cells to a predetermined voltage before terminating charge, which damages used, or older cells in the process. This is the reason a CC/CV algorithm is recommended. The CV stage of a proper algorithm prevents damage to the cells by terminating the charge at a point in the declining charge current, thus eliminating excessive oxidation of the electrodes and the heating up of the cells by overcharging. A proper CV stage also avoids the possibility of trickle charging, as well.

Have you ever wondered why Li-Ion cells charged with a hobby charger never get warm? This is because these type chargers have a proper CC/CV algorithm and the cells are not being "cooked" trying to obtain a voltage that the cells are not capable of being charged to. This is true of the Pila IBC to some extent, although a byproduct of the electronics having been built into the charger itself, is that they heat up the cells to some degree.

I never intended to hijack your thread, old, my apologies. It's just that the proper method of charging Li-Ion cells appears to be one of the most elusive and misunderstood procedures on this Forum. I think this is largely due to the fact that 19 out of 20 Li-Ion chargers discussed on the Forum, use an improper algorithm, and their popularity has caused them to be accepted as "the norm". Are they usable? Yes. Are they good for your cells? No. Are they a safety hazard? Maybe. And it's looking very much like the WF-188 is one of the infamous 19.

Dave

No not a problem , if anything , healthy debate is good ..

And I agree , the goal of the charger is to reach 4.2v .. I would love to see a charger with a trim pot that allows the user to tweak termination voltage , I think that would be fantastic .

I just would not have used the words , "force the battery" , since I did not really notice such at all , if anything this charger ran some what cool and never seemed to really warm up the batteries very much at all .

[ I say this as many folk notice there batteries getting a tad warm when charging = that would worry me a little ]

And I think to a point we might be getting away from the charger and into battery behavior , cell quality , age etc , which are really not the WF-188 fault .