WF-139 charger and 18500 batterys.

[cbxer55]

Anyone familiar with the WF-139 charger from Battery Junction?
I just got one with two 18500 batterys. When I put said batterys
into the charger, one of them turns the led green, the other red.
I am assuming the green means charged, and the red means charging?
This thing came with no instructions, so they assume some familiarity
with these types of batterys. I have been flying RC models most of my
life, and the colors are usually as I listed above.

I tried using my voltmeter on the batterys, but apparently it has gone south on me, as it reads nothing but zeros now. So looks like a new meter
for me as well.

[Black Rose]

Check the battery in your meter.

With the WF-139, the LED will be green when the cell is charged.
Depending on the version of the WF-139 (there are 3) the LED should be red during charging, with a slight green flash every second or so.

[cbxer55]

I guess that is just Ultrafires for you. Two brand new batterys, one charged to near 4.0 volts and turned the light green. The other will not even trip the light to red, and is currently at .44 volts.

Guess I get to call Battery Junction on Monday.

[ifoxbox]

I don't mean to hijack your thread, but I have a problem with my WF-139 charger. I purchased the charger and 4 new protected 14500 cells, but when I place the batteries in the charger nothing happens. How can I be sure that it is the charger and not the batteries? Are any lights supposed to light up even when a battery is not in the cradle? The cells measure 3.8 volts each. Thanks!

[cbxer55]

The lights should light up green when it is plugged in, no batterys. 3.8 sounds good to me.

Do you mean 18500s?

[FlashKat]

Try switching the batteries, and see if the other side of the charger turns red. There is a possibility the battery protection is not connecting causing a the charger to think there is no battery in the charger. I own 3 of the WF-139 chargers and they all work well.

[cbxer55]

Originally Posted by FlashKat

Try switching the batteries, and see if the other side of the charger turns red. There is a possibility the battery protection is not connecting causing a the charger to think there is no battery in the charger. I own 3 of the WF-139 chargers and they all work well.

I have done that already. I have tried every possible combination, unplugging the charger while the battery is in the slot, etc. Nothing can get past the .44 that the battery reads on my voltmeter, while the other reads 3.86.

Is'nt the low voltage cutoff somewhere around 2.50? So if it reads .44 on a meter, it is way beyond saving.

S--t happens!

[ifoxbox]

Originally Posted by cbxer55

The lights should light up green when it is plugged in, no batterys. 3.8 sounds good to me.

Do you mean 18500s?

Ok. My charger is definitely the problem since I am not seeing any lights with no batteries, and no lights when the batteries are in the charger. Thanks for letting me know. I am using 14500 Li-Ion cells which are the AA size.

Thanks again!

[mpkav]

Good timing on this thread. I was wondering about the blinking between red/green but it sounds like thats normal. How long should it take the 18500s to charge on the 139??? Thanks

[FlashKat]

There is a good possibility that the battery is good, but the protection is messed up.
If you are keeping the battery, then try measuring the battery voltage without the protection.

Originally Posted by cbxer55

I have done that already. I have tried every possible combination, unplugging the charger while the battery is in the slot, etc. Nothing can get past the .44 that the battery reads on my voltmeter, while the other reads 3.86.

Is'nt the low voltage cutoff somewhere around 2.50? So if it reads .44 on a meter, it is way beyond saving.

S--t happens!

[Redstorm]

Originally Posted by mpkav

Good timing on this thread. I was wondering about the blinking between red/green but it sounds like thats normal. How long should it take the 18500s to charge on the 139??? Thanks

I don't have the WF-139 charger but I own a WF-138 charger for RCR123 batteries and it's normal for the blinking to alternate between red and green during charging.

[cbxer55]

Originally Posted by FlashKat

There is a good possibility that the battery is good, but the protection is messed up.
If you are keeping the battery, then try measuring the battery voltage without the protection.

You got me there, what good is the battery without the protection circuit?
And how does one measure without the protection?
Is it something that once disabled, is permanently disabled?

[M@elstrom]

Originally Posted by cbxer55

Isn't the low voltage cutoff somewhere around 2.50? So if it reads .44 on a meter, it is way beyond saving.

Whilst the second cell's voltage is low the WF-139 will not charge it, I had a 18650 Ultrafire cell go like that which I placed on the 3.3v output of an old computer PSU (in the middle of my shed floor) long enough to bring the voltage up and have the WF-139 register it as chargeable... voila!

[cbxer55]

Originally Posted by M@elstrom

Whilst the second cell's voltage is low the WF-139 will not charge it, I had a 18650 Ultrafire cell go like that which I placed on the 3.3v output of an old computer PSU (in the middle of my shed floor) long enough to bring the voltage up and have the WF-139 register it as chargeable... voila!

I was considering doing something like that, just waiting for someone to step in and volunteer that it would work. You volunteered!
I will give it a try this afternoon, after I finish my morning cups of coffee.

[cbxer55]

Well it worked. I took an old plug-in charger with a 500 milli-amp (1/2 amp) output, bared the wires and wire-tied them to my voltmeter probes. Plugged in the charger and touched the probes to their respective ends on the battery, It immediately jumped from .44 to 2.4 volts and started climbing. Stopped it at 3.0 volts and dropped the battery on the WF-139 charger. It turned from green to red, currently showing 3.87 volts.

We'll see how this works out when the charger shuts off.

[tabetha]

I have a WF 139 charger, on mine the lights go green when plugged in, until you insert batteries less than charged, then they go red until charged whereupon they again turn green.
There is no flashing at all, but if you watch the light long enough you see it slowly change from red to green, it's not instant it slowly, goes pinkish faintish before coming back green when charged.
The lights on mine are a bit buggered up, but it still charges.
As regards rejecting batteries my BC700 + BC900 both do this, so I have to put in a std charger for a minute or two, to get them going in the BC chargers.
tabetha
I don't know how long for your battery size to charge, but a flat 18650 can take 8 hours no problem.
tabetha

[cbxer55]

Both batterys came off of the charger reading 4.18 volts, good thing.
Now, more than 18 hours later, after playing with it for two nights,
they are both reading 4.03 volts. So far this is acceptable to me, considering what some folks around these parts think of Ultrafire batterys.