Running tests on the WF-139. Interesting results. A must read for WF-139 users.

[Ray1968]

Interesting. I'll try the same test tonight and post the results.

Ok, my reading got up to 4.31 when the light turned green. But unlike mdocod, my DMM didn't jump up to 10-11, it only jumped up to 4.62 and stayed there. Why the difference?

The cell had a reading of 4.14 right after charging.

 

[mdocod]

Ray1968,

I explained why in the OP and again in post #7.

On AW RCR123s, the charge rate is fast enough that the charge voltage gets high enough to trip the PCB before the charge completes, this causes the circuit to go "open" and the volt-meter to read the full open circuit voltage of the charger.

If you are using a different cell, be it a RCR123 with a different PCB style, or unprotected, or a larger protected cell, then the charge will terminate by the charger at around 4.31V.

The same thing that happened with your test is what happens when I run the same test with any of my 17500 or larger cells, and the larger capacity the cell, the lower the final charge-voltage is before termination.

Eric

 

[Ray1968]

No, I meant the diffrence in this:

The 11V reading is what you would get with no cell in place but with the charger plugged in.

You're getting 11v, I'm getting less than 5v.

 

[mdocod]

Your PCB didn't trip, when the PCB trips, the charger goes open circuit and will read voltage the same as if there were no cell in place.

The ~11V reading is fine, it's the open circuit voltage of the charger and the cell is NOT seeing that voltage since the PCB has severed the circuit,

On a pair of AW brand protected 17500s:
Charge voltage was at 4.31V when the charger terminated the charge and voltage dropped to 4.22V still on the charger.

 

[harddrive]

I wonder how the wolf eyes charger performs? It is priced between the Pila IBC and the cheap Ultrafire type models. Does anyone now if the wolf eyes functions like the cheap ones or more like the Pila?

 

[mdocod]

I don't know much about the Wolf-Eyes 2-bay charger, but I do know that their "pack" chargers (tailcap and pack) use the cells PCB to terminate the charge and use a CC only charging style.

However, since their cells and chargers are designed to work together, it's not much of a problem, the problem is when you try to take a charger that works best with a few cells, and try to use it for a wider variety of cells.

 

[harddrive]

Thanks for the fast response. I think I better wait until I can afford the IBC.

 

[lightforce2]

Your PCB didn't trip, when the PCB trips, the charger goes open circuit and will read voltage the same as if there were no cell in place.

I've just set up a simulation of the PCB tripping however I'm getting the same results as Ray1968 is getting, the charger will jump from 4.28v (load) to 5.2v for a second then settle to 4.8v (open circuit) Cant get 10v or11v

My charger is terminating charge at 4.20 on battery, showing 4.28 on the DMM, the battery settles to 4.18v

Mdocod, your charger seems to be behaving differently to mine? Is your charger relativatly new?
My feeling is the older WF-139's are the one's that are trickle charging? I cant get mine to trickle charge

cheers

 

[mdocod]

Hello Lightforce2,
I think some of these discrepancies may prove that there were some design changes over the years. My WF-139 was ordered on 12-26-2006 from AW.

Just to double check and clarify a few things here:

What voltage reading do you get when you just test the charger with nothing loaded? No PCB tripping simulation or nothing, no cell in place. Cause that's all that the 11V reading on mine is, it's the total and complete open circuit no-load reading of the charger. It happens to show up when a cells PCB trips in the charger, but there is no need to simulate a cells PCB tripping to find out whether or not this voltage is being reached by the charger in open circuit condition.


Your charger, while different in some way, still appears to be using the same CC only charge algorithm, ramping the voltage up to ~4.28 on the larger cell is about what would be expected for that 18650 size cell... The larger the cell, the less voltage rise it will experience on it's way up, as it can absorb more of the charge (same charge mA rate appears "slower" to a larger cell)

Are you sure it's not the cell that's terminating the charge at 4.28V? I think that those tenergy 18650s have PCBs set to 4.25V (+/- some amount).

Eric

 

[ProofTech]

I don't know much about the Wolf-Eyes 2-bay charger, but I do know that their "pack" chargers (tailcap and pack) use the cells PCB to terminate the charge and use a CC only charging style.

The WE 2-bay chargers work in the same way as the pack chargers.

 

[Ray1968]

What voltage reading do you get when you just test the charger with nothing loaded? No PCB tripping simulation or nothing, no cell in place. Cause that's all that the 11V reading on mine is, it's the total and complete open circuit no-load reading of the charger

4.96v here. No load, no cell. Just plug in the charger and touch the test leads to the terminals. And when you do this you get 11v? This is the difference I was referring to earlier that I don't understand.

 

[mdocod]

We have confirmation that there are definitely different versions of this charger out then.

So, with that in mind.

My WF-139, that reads ~11V open circuit, has a tendency to trickle charge cells after termination.

Do the WF-139s that read ~5V open circuit have no tendency to trickle charge?

Perhaps a modern WF-139 that reads 5V open circuit could be given a higher "approval rating" if that's the case.

I'm tempted to just replace this one with an IBC and just get it over with. lol. My problem is I love the fact that it has no wall wart and nice spring loaded slots, lol.

Eric

 

[Black Rose]

I guess the big issue then is how to tell (other than with a DMM) which version a person has.

mdocod, is your WF-139 modded to activate the RCR123 bays?

 

[Exit32]

I measured 4.85 open-circuit volts on my one-month-old WF-139. Tested both slots (empty) with DMM and got same result for both.

 

[lightforce2]

We have confirmation that there are definitely different versions of this charger out then.

Yes, I'm suspecting this too. My general observation has been that forum membes who have raised the 'trickle charge' issue seem to have older WF-139's

Do the WF-139s that read ~5V open circuit have no tendency to trickle charge?

This seems to be the case with mine

Your charger, while different in some way, still appears to be using the same CC only charge algorithm, ramping the voltage up to ~4.28 on the larger cell is about what would be expected for that 18650 size cell... The larger the cell, the less voltage rise it will experience on it's way up, as it can absorb more of the charge (same charge mA rate appears "slower" to a larger cell)

I wondered about that, thanks for confirming it

Are you sure it's not the cell that's terminating the charge at 4.28V? I think that those tenergy 18650s have PCBs set to 4.25V (+/- some amount).

I have a Tenergy cell with a hole in its plastic cover exposing the - terminal, so I'll bridge out its PCB & charge it to determine whether the charger or the PCB is terminating current.
I'll also check the open voltage again and post results tonight

Cheers,

 

[mdocod]

Sweet, looking forward to hearing the results. If Modern WF-139s are just using a CC stage, but do terminate without a trickle around 4.20V, then that wouldn't be to bad.

Eric

 

[lctorana]

I definitely think that an open-circuit voltage of 11V is just plain wrong.

Whether or not the UF-139 turns out to be too harsh on batteries, yours is a dud.

(Mine gives 5.03 / 5.02 OC, btw)

 

[jirik_cz]

Mine WF-139 has 5.00V open circuit voltage.

I've tried the same test as mdocod, but with UNprotected cell.
Voltage during the end of charge was 4.24-4.25V, when the light goes green it goes immediately down to 4.14-4.15V and stays there. No change after many hours so no trickle charge.

I have also "Digital Li-Ion 18650 Battery Charger" with two bays from DX. Open circuit voltage is 4.18V. The light goes green when batteries reach 4.14V after that it trickle charges to 4.18V and stops completely there.

 

[PhantomPhoton]

I have an older WF139 that I purchased from Lighthound in February of 2007.
Mine has an open circuit voltage of around 11.5V.

I tested my WE dual bay charger and it jumps around from 3.9-4.5V

Perhaps I'll take a look with the meter some time when I'm charging an 18650 in both of them.

 

[FlashSpyJ]

My WF-139 was bought maybe a year ago. I read 11.42V and 11.44 with no load.

On the back of the charger it says that you should only charge 14500, 17500, 18500, 17670, 18650 batteries. I have charged my AW RCR123 a couple of times with no trouble so far...