greatest danger using li-ion cells occurs during re-charging

[Black Rose]

JSB is busy with his other ventures.

Both were and still are respected members of this community. :twothumbs

From Newbie I learned so much about led die fabrication and inductor choice and the technology thats going into them these days

From JSB I learned to treat customers right even at a loss and the results will be reaped over time. The free shipping idea is from him

In case others reading this weren't aware, JSB has fallen on hard times lately.

You can read about his recent 700 mile walk over at EDCF.

 

[VidPro]

OK quick question...

I have a $5 smart charger that automatically chooses the voltage, and charges about a little under 200 mAh I hear... Its supposedly rated at 380, but it appears to take longer than 2 hours to charge a 14500. Furthermore, it won't charge past 4.17 volts. It'll stop, wait for the battery to drop below 4.17, then charge it back to 4.17. Left if for hours on end and it won't get any higher.

Is this a "safe" charger for unprotected 14500s?

[BTW sku.14885]

automatic is never "safe" but then again neither is some peoples manuel
from the specs you presented this is (about) how you would want it to work, just you should not leave it on the charger anyways, that is just asking for some high tech piece of junk to bite you.
also manually check your cells for self discharge (especially the 14500s) to insure that they are still alive, most do not last good time, although at the RATE of charge it is unlikly to cause any ignition, still a user knowing that the battery still works before jamming it into any charger is some of the safest things you can do.
AND
NEVER use this auto junk on an SERIES set, specially with Un-protected, you always want balancing or singular channel charging or finishing at least. you CAN "get away with" series charging with protected cells, but not at all with unprotected.
Protected cells will just not be all charged the same,
unprotected the charge differential has no singular cutoff,
so although the TEAM could be within the (say) 8.4V for 2,
3.8V+4.6V still equals 8.4v and i think you can see the problem with that.

 

[LOUSYGREATWALLGM]

Can you tell me what are the things to do to determine that the batteries are still good to recharge?

 

[VidPro]

Can you tell me what are the things to do to determine that the batteries are still good to recharge?

the voltage "holds" on li-ions when they are good, normal good cells have very very low self discharge, in fact i can have one sit charged for 6months, and not even know it wasnt fresh charged.
(some protection curcuits can have a tiny parasitic discharge of the cell, so protected is different)
they should not heat on the charger , this goes hand in hand with the rest of the stuff, a bad one will not "accept" a charge as readily, depending of course on the rate.
The capacity should be at LEAST 50% (if not 80%) of what it was when it really was new, this also goes hand in hand with higher self discharge, and charge acceptance.
if the capacity or your runtime with it compared to what your used to, drops severly, then it is suspect.

li-ions that the voltage has dropped below 2.4v and been that way for a long while, usually are not going to be good after that, even if they seem ok at first.
(protected cells that read 0v could be cut-off and at ~2.4-2.7v depending on the curcuit)

14500s (because that was discussed previous) that are neer 2 years should be suspected, most of the 14500 i have tested over long term do not hold up :-(

 

[recDNA]

Yes, there have been recorded cases of primary lithium cells exploding in flashlights. There are several threads around here about those incidents.

With brand name cells, it was caused by using mismatched cells (different voltage levels) in a multi-cell light. That results in the stronger cell reverse charging the weaker cell.

With cheap no-name Chinese cells, they were caused by QC issues.

I've been following your posts and concerns you've raised about lithium cell safety (primary & rechargeable).

I can relate to your concerns about rechargeables. It took me close to a year of reading various threads on here before I decided to get into Li-Ion rechargeables.

PS - I've read about inscidents of gas leakage and liquid leakage and explosions in chargers but I've missed the threads about flashlights being turned into shrapnel.

It was only after reading and absorbing all of the information and knowing full well what I was getting myself into did I get into Li-Ion cells.
I am glad I did, as it opened up many new lighting possibilities that I otherwise would have missed out on.

Keep in mind that these issues, while they can happen, are rare.
You as the end user need to take precautions and be aware of what you are doing.

My father-in-law absolutely loves my Solarforce L2 lights and would love to have one, but there is no way in hell I would ever get him kitted out with one simply because he is so careless when it comes to batteries, especially rechargeables.

Yes, I intend to stick to SINGLE 18650 or the thinner version (17 something) flashlights to diminish the odds of an incident. I'm leaning toward Trustfire cells rather than AW because they are half the price and folks here seem to favor them over Ultrafire when it comes to safety.

I like pocket rockets so no need for a double 18650 flashlight. I have my TK40 when something bright and big is required. I haven't been able to find the Stanley HID at any local Walmarts but that's in my future as well.

I do have lots of lithium primaries in AA and CR123A size and now I'm worried about them as well. They do get hot in the flashlight and the ones in my car get very hot in the sunlight. It appears up to 140 degrees is safe from what I've read but car interiors can go to 150.

My TK40 with ultralithiums doesn't get very hot but the MG PLI does get pretty warm with lithium primaries. It's not too hot to hold but I need to check battery temperature to make sure it stays below 140 F. I think the PLI will be a little safer with 18650's than lithium primaries when in high mode.

It would be cool to conduct a poll of all CPF members to see how many have had serious incidents with Li-ions and LiMnO cells. I don't dare do it because somebody will jump down my throat for repeating some old thread but with your credibility it could get a good response.

I don't think you will hiding it in this section though. It will have to be in the LED section to get the viewership we need for good data analysis. Of course if I post such a poll in the LED section it would be moved but if YOU did....

If I were an EE doing a graduate thesis on this subject I know I would want to tap this pool of users for a scientific survey.

 

[recDNA]

I've seen threads about batteries venting in flashlights or exploding in chargers but have any flashlights actually been turned into shrapnel?

Oh, and is the dual pocket charger in batterystation now the same as the Yoho 122?

 

[Rexlion]

I bought a modded 18650 light in the marketplace and it came with a battery. I tried putting it in the charger and it didn't want to fit. In the process of trying, the top button got slid over to one side. I recentered it with my finger, then got to looking at the battery... and realized it was not a 18650 but a 18700. :huh: It says SenyBor CGR18700A on it.

My main question is, may I have damaged the battery when the top button got shoved over?

The seller suggested that I could recharge it by running wires from the charger contacts to the battery ends. What is the general feeling on this?

FWIW, the battery feels like it has a protection strip running down the side.

Oh, I just remembered one more question: is it ok to touch multimeter leads to the contacts while a battery is charging? I wasn't sure if it might damage the meter or do something else. I was curious about trying to take a voltage reading a bit before the charge cycle ends, if possible.

 

[Black Rose]

Oh, and is the dual pocket charger in batterystation now the same as the Yoho 122?

Yes it is. I bought two of those in the last few months.

 

[Rexlion]

I bought a modded 18650 light in the marketplace and it came with a battery. I tried putting it in the charger and it didn't want to fit. In the process of trying, the top button got slid over to one side. I recentered it with my finger, then got to looking at the battery... and realized it was not a 18650 but a 18700. :huh: It says SenyBor CGR18700A on it.

My main question is, may I have damaged the battery when the top button got shoved over?

The seller suggested that I could recharge it by running wires from the charger contacts to the battery ends. What is the general feeling on this?

FWIW, the battery feels like it has a protection strip running down the side.

Oh, I just remembered one more question: is it ok to touch multimeter leads to the contacts while a battery is charging? I wasn't sure if it might damage the meter or do something else. I was curious about trying to take a voltage reading a bit before the charge cycle ends, if possible.

>> Bumping these questions, still hoping for some answers. . . . . . . . :wave:

 

[flasohollic]

>> Bumping these questions, still hoping for some answers. . . . . . . . :wave:

Your battery should be fine..

Yes if the battery have protected circuit it would have a metall strip on the side,, this make the circuit.

Running wires to side is noe issue,, but be carefull nor to make them contact each other (shorting)

its very clever to use a multimeter to check the voltage and current if you dont trust the charger\battery, doing so is no issue at all.

 

[flasohollic]

>> Bumping these questions, still hoping for some answers. . . . . . . . :wave:

There is noe issue to use a multimeter, its a must if you dont trust the charger\batterys voltage ore current.

It doesnt mather how you contact the batterys to the charger, just make sure not to make a short circuit and + and - is correct


The battery is a metall casing so i dont think you have damaged it

 

[Rexlion]

Thanks very much, I appreciate the answers. I definitely wanted to be cautious and ask before doing something with lithium rechargeables that I hadn't done before.

 

[325addict]

Just because these accidents (selecting wrong number of cells in a misty menu) can and WILL happen now or in the (near?) future, I decided to design and build my own charger.
It meets ALL criteria for a safe (and by that, I mean a SAFE!) charger:

1. Charging voltage: exactly 4.200V
2. NO trickle charge
3. charging cutoff at point where current falls under 3% of rated capacity
4. charging doesn't start when cell voltage (in rest) is under 2.5V
5!! an extra protection is built-in: as soon as the voltage comes above 4.25V for ANY reason, the charger will shut down for as long as this error occurs.

Furthermore, charging current can be selected: 250mA, 500mA or 1A. This is the ONLY user-selectable setting and won't cause fires as long as you don't try to charge a 10180 cell at 1A.
LED's will tell you:
1. CC charging at the moment (red)
2. CV charging at the moment (yellow)
3. ready (green)
4. < 2.5V (no charging possible then!) RED LED
5. error (charging voltage is above 4.200V maybe due to an internal defect)
RED LED too.

This one I will leave unattended at night if it has to be. Of course, I'd rather keep an eye on it, but WHEN it sometimes just has to do without that eye, I know it's protected with that extra safety-circuit.

By the way, I got a batch of DSD chargers that charge up to 4.26 Volts!
So.... SAFE??? Not really :mecry:

Timmo.

 

[recDNA]

What would be the best thread for me to read about the df between Li-Ion and Li-Poly batteries? I've read a few that weren't very good.

 

[cy]

ah... my old thread... back from the dead

 

[Kestrel]

ah... my old thread... back from the dead

Well, quality never goes out of style... :thumbsup: