I fell asleep on Ultrafire WF139

[LightWalker]

I was charging a couple of 14500 batteries on my Ultrafire WF139, an unprotected Ultrafire and a protected Trustfire and I fell asleep.

I woke up the next morning and checked the voltage and both batteries were showing less than 4.2V. :thumbsup:

I usually watch the charger to avoid overcharging but it seems the 139 (at least my sample) does a good job at cutting the charge.

 

[mighty82]

I charge batteries when I sleep all the time.. But I keep all my chargers on a metal surface. Worst case scenario, I loose a couple of batteries and the charger. I don't have time to babysit my chargers, there is usually something charging at all times.

 

[rizky_p]

I charge batteries when I sleep all the time.. But I keep all my chargers on a metal surface. Worst case scenario, I loose a couple of batteries and the charger. I don't have time to babysit my chargers, there is usually something charging at all times.

Not a good practice and not something you would recommend to anyone.

 

[mighty82]

Not a good practice and not something you would recommend to anyone.

Why? There is no risk to anything besides the battery and the charger. Even if i'm there, I probably won't know the charger has missed termination before it's to late for the battery anyway. I always charge batteries at least 1 meter from any flammable materials, and I always keep batteries in fire proof bags. (something I learned from dealing with unstable lithium polymer batteries ). Of course I unplug all chargers if i'm away for more than a few hours.

 

[matrixshaman]

If you are going to leave them unattended it would be better to have them enclosed in metal than just sitting on metal. If a battery blows some will shoot hot flaming bits far enough to be dangerous to surrounding flammable material. I usually only charge while I'm on the computer or sitting nearby.

 

[LumenHound]

I was charging a couple of 14500 batteries on my Ultrafire WF139, an unprotected Ultrafire and a protected Trustfire and I fell asleep.

Perhaps it's time to retire that WF139. You shouldn't have to put up with even the smallest nagging doubt when it comes to li-ion chargers.

 

[Illum]

I charge batteries when I sleep all the time.. But I keep all my chargers on a metal surface. Worst case scenario, I loose a couple of batteries and the charger. I don't have time to babysit my chargers, there is usually something charging at all times.

I do the same, charge cells overnight, when daylight cracks the horizon I'm out and about and when the sun has set then I return from school or work. Its not intentional, but I don't have the time to charge them in another time....
5 hours of sleep charges cells pretty well,
AW PROTECTED CELLS ONLY!

 

[LightWalker]

Perhaps it's time to retire that WF139. You shouldn't have to put up with even the smallest nagging doubt when it comes to li-ion chargers.

My WF139 is brandnew and works perfectly. I'm just very cautious (and a little paranoid) when charging and discharging Li-ion batteries.

 

[LightWalker]

I charge batteries when I sleep all the time.. But I keep all my chargers on a metal surface. Worst case scenario, I loose a couple of batteries and the charger. I don't have time to babysit my chargers, there is usually something charging at all times.

What charger are you using? Have you had any problems with overcharging or battery failures?

 

[mighty82]

What charger are you using? Have you had any problems with overcharging or battery failures?

I had the WF-139. Never had a problem. I have been using the new trustfire TR-001 the last couple of months. And a few computer chargers for checking capacity and stuff.

 

[lightforce2]

I woke up the next morning and checked the voltage and both batteries were showing less than 4.2V. :thumbsup:
I usually watch the charger to avoid overcharging but it seems the 139 (at least my sample) does a good job at cutting the charge.

I've done exactly the same thing with 18650's in my WF139, when I realized they were still on the charger the next morning I was a bit concerned as I had read about the 139's trickle charging, however and they came out at 4.18v
When in the supamarket I came across a cheap Kambrook digital countdown timer that plugs into the wall socket, bought it & set it for 5 hours max, nice piece of mind!!

 

[linterno]

I was charging a couple of 14500 batteries on my Ultrafire WF139, an unprotected Ultrafire and a protected Trustfire and I fell asleep.

I woke up the next morning and checked the voltage and both batteries were showing less than 4.2V. :thumbsup:

I usually watch the charger to avoid overcharging but it seems the 139 (at least my sample) does a good job at cutting the charge.

Recently I started to use Li-Ion batteries. I have to confess I was/am really afraid of "explosion" or "vent with flame". I Bought 2 Ultrafire 17500 for my Romisen RC-W4, 2 Trustfire 16340 (RCR123) for my Romisen RC-N3 and a DSD charger, everything from DX. The first time I inserted one 16340 battery which finished charging at exactly 4.2V. I thought, this is an excellent charger. Then next 16340 charged to only 4.15 volts. The 17500 charged both to 4.15 volts. From what I have read here in the forum, charging Li-Ion batteries to 4.15V is good since the batteries live will be longer. Up to here the history was good. I remembered I had an old DELL battery and disassembled it to get 8 unprotected 18650 batteries. I inserted one battery into the DSD charger. I took 10 hours to reach 4.2 volts in the charger, but this didn't stop charging. Since I have read that Li-Ions can reach 4.25 +-0.05 volts I tought that would be good to let the charger continue (I was taking voltage reading every half an hour). The next time I took the reading the batteri was charged to 4.6 volts, so I removed it from the charger (it was an unprotected and old battery so I didn't want it to vent). At this moment I tought "well, this charged is not as good as I tought". A couple of days after I inserted one of the 16340 batteries I had charged before. This time the battery voltage reached 4.2 volts and the charger continued charging the battery. Since I wanted to see how efficient the protection circuit was, I left the battery in the charger until the voltage reached something close to 4.29 volts. I Removed the battery from the charger before it finished.

My point here is: Don't trust your WF-139 just because the first time you got the perfect charging voltage. Be careful Don't even believe that leaving the charger in a metallic surface is good. When venting the battery can jump far away and something can get fire.

 

[LightWalker]

Recently I started to use Li-Ion batteries. I have to confess I was/am really afraid of "explosion" or "vent with flame". I Bought 2 Ultrafire 17500 for my Romisen RC-W4, 2 Trustfire 16340 (RCR123) for my Romisen RC-N3 and a DSD charger, everything from DX. The first time I inserted one 16340 battery which finished charging at exactly 4.2V. I thought, this is an excellent charger. Then next 16340 charged to only 4.15 volts. The 17500 charged both to 4.15 volts. From what I have read here in the forum, charging Li-Ion batteries to 4.15V is good since the batteries live will be longer. Up to here the history was good. I remembered I had an old DELL battery and disassembled it to get 8 unprotected 18650 batteries. I inserted one battery into the DSD charger. I took 10 hours to reach 4.2 volts in the charger, but this didn't stop charging. Since I have read that Li-Ions can reach 4.25 +-0.05 volts I tought that would be good to let the charger continue (I was taking voltage reading every half an hour). The next time I took the reading the batteri was charged to 4.6 volts, so I removed it from the charger (it was an unprotected and old battery so I didn't want it to vent). At this moment I tought "well, this charged is not as good as I tought". A couple of days after I inserted one of the 16340 batteries I had charged before. This time the battery voltage reached 4.2 volts and the charger continued charging the battery. Since I wanted to see how efficient the protection circuit was, I left the battery in the charger until the voltage reached something close to 4.29 volts. I Removed the battery from the charger before it finished.

My point here is: Don't trust your WF-139 just because the first time you got the perfect charging voltage. Be careful Don't even believe that leaving the charger in a metallic surface is good. When venting the battery can jump far away and something can get fire.

Thanks for the advice. The WF139 Is actually my second LI-ion charger but I don't have a lot of experience with them and I have read of overcharging and battery failures and venting on here so I prefer to monitor charging.

 

[Norm]

When in the supamarket I came across a cheap Kambrook digital countdown timer that plugs into the wall socket, bought it & set it for 5 hours max, nice piece of mind!!

Good simple idea.

 

[matrixshaman]

A timer's a good idea but if something goes wrong it can happen in a lot less than 5 hours. Attended charging is best and next best is charging in a bullet proof (so to speak) enclosure.

 

[Bimmerboy]

A timer's a good idea but if something goes wrong it can happen in a lot less than 5 hours. Attended charging is best and next best is charging in a bullet proof (so to speak) enclosure.

+1.

Call me paranoid, but I don't even "trust" my Pila IBC, and protected AW's. I do NOT charge Li-ions unattended, or when there's a chance of getting sleepy.

To try to extend Matrixshaman's statements... A timer set for 5 hours is great peace of mind if your NiMH charger misses termination, but definitely set it shorter for Li-ion. If you know the time it takes to charge a particular batt on a particular charger, AND the approx. state of charge of your batteries, set the timer just slightly longer than what's needed.

 

[xonid]

Would a military ammo can/box be safe to charge in? Usually $5 at a local surplus store.

simple and cheap.. thoughts?

Edit: Without the ammo of course...

 

[Inspgad]

Would a military ammo can/box be safe to charge in? Usually $5 at a local surplus store.

simple and cheap.. thoughts?

Edit: Without the ammo of course...

Perhaps this is better as it's supposed to vent the gases in a controlled way instead of explosively like a bomb???

http://www.liposack.com

Anybody have any personal experience with this product?

 

[mighty82]

Perhaps this is better as it's supposed to vent the gases in a controlled way instead of explosively like a bomb???

http://www.liposack.com

Anybody have any personal experience with this product?

Yes. I use them when i'm charging rc batteries (lithium-polymer). I store them in an alumunium briefcase when not in use.

 

[rizky_p]

Why? There is no risk to anything besides the battery and the charger. Even if i'm there, I probably won't know the charger has missed termination before it's to late for the battery anyway. I always charge batteries at least 1 meter from any flammable materials, and I always keep batteries in fire proof bags. (something I learned from dealing with unstable lithium polymer batteries ). Of course I unplug all chargers if i'm away for more than a few hours.

why? because not everyone really understood what the risks are. I uses RC charger and still doesnt leave it overnight. Not worth the risk IMO.