Should WF-139 Get Hot??? Nervous!

[kramer5150]

Mine gets warm too. Not what I would call hot though. Mine charges the cells to 4.17V.

In the summer I put a small fan next to the charger to keep cool air on it.

 

[old4570]

Warm up top . check the bottom of the charger , either hot or very warm ..

If you use something to heatsink the bottom , then it will run cooler .
Or dont charge 2 batteries ?
If you only charge one at a time , it will run much cooler .
Also depends on how depleted the batteries are :

and if your really worried , cut some holes in the body ...

 

[Lightcrazycanuck]

I have several chargers that get a little warm from time to time, even my C9000. It is normal for power electronics to get hot in operation. I'd say that as long as the outer body of the charger is not too hot to comfortably touch, and as long as it is not emitting smelly plastic vapors (the best way I can describe overheated plastic), then everything is OK. If it is hotter than that you are right to be suspicious. But don't confuse very warm with hot. For battery chargers to generate heat and get warm is by no means unusual.

Agreed.:thumbsup::thumbsup::thumbsup:

 

[recDNA]

Interestingly, the charger doesn't even get perceptably warmer than room temperature when charging an IMR 16340 and an IMR 18650 simultaneously. Must be the lower maH capacity. The IMR 16340 does charge much faster. It's at 4.13 V nowand I'm checking every 5 minutes to make sure it doesn't get too high. I would normally stop at 4.13 but I'm curious to see if the green light comes on for my little IMR as it does for the 2600 maH 18650.


I'm using a bolt as a spacer. Seems to work fine.

Oops it just turned green. Good. When I checked voltage it was a little higher than I would like - 4.21 volts. The 18650 finished at 4.19 Volts. I definitely need to be here every minute with the IMR 16340. I don't know how much higher it would have gotten if left on. I got it out within one minute of the light turning green and it was already a little high. I understand that even after the light turns green ??? True? If the battery continues to charge another half hour it may have popped. No protection in IMR's

 

[alfreddajero]

As long as the conenction is made there would be no problem at all.....I guess the reason why the op's gets warmer or hotter however you want to put it is because he's charging higher capacity cells.

 

[recDNA]

As long as the conenction is made there would be no problem at all.....I guess the reason why the op's gets warmer or hotter however you want to put it is because he's charging higher capacity cells.

As I just edited into the post below, however, the IMR 16340 charged to a little higher voltage than optimal and I got to it as soon as it turned green. If left alone with the green light on would it have continued to go to higher and higher voltage until :poof:???


I got a surface temp reader from the lab and I'm going to graph the temp the next time I charge the 18650's.

 

[alfreddajero]

Hey buddy i was checking around the other battery providers for that cell and came across this......From LightHound, you might find it useful. It seems to me that you just met the safety zone.

[SIZE=+3]Attention :[/SIZE] These IMR cells have much lower internal resistance than regular LiIon 3.7V cells and they may end up with a higher ending voltage when charged in certain chargers ( especially older version WF-139 charger ). Please check the voltage of them right out of the charger to see if they are above 4.20V when fully charged with your charger. Overcharging above 4.25V may shorten life/cycles. Above 4.50V may even pop them or making them leak. DO NOT use the charger if it seems to overcharge IMR cells.

 

[recDNA]

Hey buddy i was checking around the other battery providers for that cell and came across this......From LightHound, you might find it useful. It seems to me that you just met the safety zone.

[SIZE=+3]Attention :[/SIZE] These IMR cells have much lower internal resistance than regular LiIon 3.7V cells and they may end up with a higher ending voltage when charged in certain chargers ( especially older version WF-139 charger ). Please check the voltage of them right out of the charger to see if they are above 4.20V when fully charged with your charger. Overcharging above 4.25V may shorten life/cycles. Above 4.50V may even pop them or making them leak. DO NOT use the charger if it seems to overcharge IMR cells.

Yes, I saw that too. It's also on the AW thread in the marktplace but 4.21 isn't that bad is it? Of course I don't know if it would have continued to climb even after the charger turned green. Keep in mind I have the NEWER version of this charger.

 

[alfreddajero]

I do too.....and mine come off the charger at 4.15-4.17, but my 16340's are the black labels. I would check the voltage on the next go around just to make sure that it wasnt a small fluke. Too me the cells were on the border to whats allowed.

 

[recDNA]

I do too.....and mine come off the charger at 4.15-4.17, but my 16340's are the black labels. I would check the voltage on the next go around just to make sure that it wasnt a small fluke. Too me the cells were on the border to whats allowed.

Doesn't appear to be a fluke. IMR 18650 turned green at 4.22 volts. It's below 4.25 max but not where it should be. In the future I'll monitor and remove from charger at around 4.15 so as not to overcharge again. Of course I'm assuming the multimeter is measuring accurately but it shows AA primaries at 1.2 volts as it should.

I also use a timer so in the event something pulls me away the cells won't charge indefinitely. I set it at 30 min intervals so if I forget to check the charger won't stay on.

I'll tell you though - my single 18650 MC-E is BLAZEN bright with the IMR 18650 instead of the ordinary 18650.

I don't know why but my Quark TI 123 is actually a little brighter on a primary CR123 than the IMR 16340.

My ordinary Li Ions come off right at 4.19 volts as they should.

 

[alfreddajero]

Well the IMR's are made for higher amperage applications arent they.....i hear good things about the AW IMR's and would not mind a few in my arsenal. Where did you get the charger by the way.

 

[recDNA]

Well the IMR's are made for higher amperage applications arent they.....i hear good things about the AW IMR's and would not mind a few in my arsenal. Where did you get the charger by the way.

Just arrived this week from Lighthound. I wonder if anybody's WF-139 does NOT charge over 4.2 volts on IMR's?

I just feel like 4.22 volts isn't that bad. Now I know I need to check it as it charges and I'll get it off the charger sooner. The 16340 charges in a jiffy and the IMR 18650 charges twice as fast as my AW 18650 2600.

I don't dare take the chance but I'd love to know if I had left them there another 30 - 60 minutes on green light in the WF-139 how high the voltage would have gone. If it won't go higher than 4.23 volts I wouldn't worry at all but I'll never know.

 

[Mr Happy]

They aren't really going to go pop unless you seriously overcharge them (e.g. 4.5 V or more). At 4.3 V they will still work but you will lose cycles and get a much shorter working life. The main reason for not going above 4.2 V is to optimize the service life. If you do what you are doing and remove them as soon as the green light comes on you will be fine.

 

[alfreddajero]

Well on a good day you can charge the cells outside and see what happens....just set up a little station using an extension cord away from living bodies. The IMR should charge faster since the capacity is a lot lower then the black label.

 

[recDNA]

They aren't really going to go pop unless you seriously overcharge them (e.g. 4.5 V or more). At 4.3 V they will still work but you will lose cycles and get a much shorter working life. The main reason for not going above 4.2 V is to optimize the service life. If you do what you are doing and remove them as soon as the green light comes on you will be fine.

Well I never actually got to 4.3 V. The IMR 18650 got to 4.22 volts and the IMR 16340 got to 4.21 volts. My mention of 4.3 was a hypothesis of what may have happened if left on charger with green light on.

When the WF-139 charger light turns green will IMR cells continue to be charged to higher and higher voltage?

 

[Mr Happy]

When the WF-139 charger light turns green will IMR cells continue to be charged to higher and higher voltage?

I don't know, but you can safely test and find out. Once you know the voltage they get to as soon as the green light comes on, try leaving them on the charger for half an hour longer, an hour longer, two hours longer and see what happens. If you take them up to 4.3 V one time only it won't hurt very much as long as you drain them down a bit afterwards. It is repeated charging to high voltage, or storing at high voltage that shortens their life.

 

[recDNA]

I don't know, but you can safely test and find out. Once you know the voltage they get to as soon as the green light comes on, try leaving them on the charger for half an hour longer, an hour longer, two hours longer and see what happens. If you take them up to 4.3 V one time only it won't hurt very much as long as you drain them down a bit afterwards. It is repeated charging to high voltage, or storing at high voltage that shortens their life.

I noticed the IMR18650 that was charged to 4.22 volts dropped to 4.20 on its own within an hour.

 

[digitor]

Of course I'm assuming the multimeter is measuring accurately but it shows AA primaries at 1.2 volts as it should.

A fresh AA Duracell measures around 1.6V - if your meter is showing 1.2V on an AA primary cell, maybe you should get it checked!

Cheers

 

[recDNA]

A fresh AA Duracell measures around 1.6V - if your meter is showing 1.2V on an AA primary cell, maybe you should get it checked!

Cheers

Typo on my part. I tested my IMR 18650 with my old analog meter and the new digital meter and both read exactly 4.2 volts now. The battery was 4.22 fresh out of the charger but for some reason the voltage dropped.

As for testing outdoors risking popping a battery I think I'll pass and just test voltage every 30 min and quit charging as soon as I get between 4.15 and 4.19 I won't wait for "green" light again with IMR. Works fine with AW 2600 anyway. Maybe I'll get a Pila someday...

 

[alfreddajero]

You and me both...would love to have a high end charger.....the ones that do lith duty are good for now.