5.25V on a 10440

[Ward]

Today I got my titanium LF2XT!
Now I've been playing around with it a bit, and found a problem with the batteries:

One of them has a voltage of 5.25. What will happen when I put it in the light?

 

[grunscga]

I'm not an expert in these things, but I do use Li-ions on a regular basis, and so all I can tell you is what I'd do:

There is no way I'd put that in the light. That's what, 25% more voltage than the light is designed to handle? You're bound to fry something, probably in the buck circuitry.

I would also contact whoever you got the batteries from and arrange for a return, because anything over 4.2V is a bad thing. I know AW says that anything over 4.25V on one of his batteries could cause it to burst. Obviously, yours hasn't (yet), but I wouldn't give it the chance.

Personally, I'd seriously consider storing it somewhere safe until you can get rid of it, like in an un-sealed coffee can in the garage far away from flammable items. AW also says that abused batteries can take several days to start leaking (if they are only mildly abused), so I wouldn't want it to leak all over anything important while I waited to ship it back.

 

[ma_sha1]

Today I got my titanium LF2XT!
Now I've been playing around with it a bit, and found a problem with the batteries:

One of them has a voltage of 5.25. What will happen when I put it in the light?

I didn't know this is possible, I thought the cell chemistry dictate the max volt, Never heard a Li-ion volt go up that high, could it be a bad meter? If not, then def. don't use it.

 

[McAllan]

If there's nothing wrong with the meter then that cell could easily go visit this guy: :devil:

Personally I'd discharge the cell slowly say via 100 ohm resistor in a fireproof place/container and then send the cell to recycling.

If the cell came out of your charger with that high voltage - then get a decent not to mention safe and appropriate charger!

 

[45/70]

......One of them has a voltage of 5.25......

While I won't say that it's not possible, but usually at that voltage a LiCo Li-Ion cell will "vent with flame". I suspect that either the battery(ies) in your meter are going bad, or the meter is defective.

At any rate, I would measure the voltage with another meter and report back with the results.

Edit: Oh, and nice light!

Dave

 

[jasonck08]

I'm surprised it did not blow up or vent at that kind of voltage! I've not seen a Li-on go much above 4.5v before!

 

[SilverFox]

Hello Ward,

At 5.25 volts I am waiting for the BOOM so I can move this thread to the "Smoke and Fire" section...

Tom

 

[Illum]

sure your meter isn't set at microvolts?:thinking:

 

[mdocod]

Hello Ward,

The meter is either giving an improper reading or being used incorrectly. Check the battery/s in the meter. It's almost impossible to get a LiCo cell above ~4.5V without it either exploding, flaming, or having a a PTC style protection kick in and shut down the cell permanently.

Use a different meter and see what you measure.

Eric

 

[Ward]

Ok my bad, the meter wasn't set right

There is a problem with the cells though; they don't hold a charge.
I've contacted Steve Ku, whom I bought the cells and the beautiful Ti light from, and he immediately offered to to send a couple of new batteries. Great service!

Anyways, thanks you guys for the response!

Ward

 

[Mr Happy]

There is a problem with the cells though; they don't hold a charge.

Could it possibly be you damaged them by using the meter on the wrong setting?

 

[Ragiska]

i have a feeling the meter was set on DCA and not DCV, which would explain everything, including the "dead cells"

 

[Ward]

I honestly don't know...
Could it? I've been using Li-ions for quite a while now, in different sizes, and never had this problem. I'm still guessing bad cells.. Thanks anyway.

 

[McAllan]

Well, if You've put it on the 10 A range (some meters require you to use another plug for positive) then that's quite possible.
On the typical 200 mA range there should be a fuse so that shouldn't have caused much harm.

 

[Illum]

Could it possibly be you damaged them by using the meter on the wrong setting?

5.25 amps....so it would mean it dumped a little more than 10C

 

[mdocod]

If you did accidentally use your meter and test amps, and did this for more than a few seconds on more than a few occasions, then you may want to go ahead and send payment for those replacement cells.

 

[zipplet]

Please be extra careful using a DMM like this. If you repeat this mistake (DC amps, 10A setting) on a lead acid battery the probes may weld themselves to the terminals and you will have a very nasty short on the order of 500-1000 AMPS!

NiMH packs aren't that tame either.

 

[McAllan]

Please be extra careful using a DMM like this. If you repeat this mistake (DC amps, 10A setting) on a lead acid battery the probes may weld themselves to the terminals and you will have a very nasty short on the order of 500-1000 AMPS!

NiMH packs aren't that tame either.

It depends. I've had many small lead acid packs. Mostly the sealed ones. You don't get anything near 100 amp from a small 1 Ah one. Even the 10 Ah SLA ones had their troubles - unless of the cranking type like an MC battery.
Neither do you get that from a bunch of serial AA cells. But non sleeved D size and high current sub-C cells though can be quite nasty too. At least they don't risk venting with flame but red hot wires are not to play with either.
Remember when I was a kid and my uncle had a 12 v pack made of 7 Ah (or was it 8 Ah?) high current F sized NiCd cells. They could literally pull a train! (or, well, we never tried but you get the idea )

 

[liveforphysics]

I did some extreme over-voltage testing with 10440's, RCR123's, 18650's, and 26650's.

Even by-passing the cell's safety protection on the top of the cell, I was not able to make ANY of the cells explode through over voltage or over charge up to 7v. I even did some 10C charging to 7v and could get them toasty warm, but no explosions.

I for years I would handle a LiCo cell with a 4.5v resting voltage like it was a mini-firebomb, discharge and dispose of them.

I don't know if modern cell types are just more durable than the old cells, or if the whole problem was just over-stated to begin with, but I was shocked to find myself unable to cause catastrophic failure through over-charge/over-voltage.

Here is a quick highlights video with some of my more exciteing lithium cell tests.

http://www.youtube.com/watch?v=dree0rTr1HM

 

[liveforphysics]

Please be extra careful using a DMM like this. If you repeat this mistake (DC amps, 10A setting) on a lead acid battery the probes may weld themselves to the terminals and you will have a very nasty short on the order of 500-1000 AMPS!

NiMH packs aren't that tame either.

I've never seen a meter that wasn't fused on the amperage measurement setting...

Pulling 500-1000amps through 6ft of 16awg meter leads and the shunt resistance would be quite the trick as well.