Over discharged batteries.

[awj03130]

Hello all...

I over discharged an MNKE 26650 yesterday. From what I've heard, if a battery goes below 3.1 volts, its unsafe to charge again.

But, here's the kicker - xtar's website lists an over-discharge function that can save batteries. Is it too dead to charge, will it explode or vent while charging, is it unsafe to use when charged again, or is it totally OK?

From xtar's website:

http://www.xtarlight.com/05-chanpin/p-001-1.asp?styleid=233&style=Charger Series

And from today:

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[MorpheusPA]

The lithium cobaltite at the anode is gone at around 2.3 volts, and if it were testing that low I'd tell you to toss it immediately and make no attempt at restoring it. In your case, you've lost a considerable amount of it, but not all. There's still enough that you may be able to get the battery to come back on a recharge, but I wouldn't expect normal remaining lifespan from the battery at this point, either.

It might be worth an attempt to bring it back, but if you do so then I'd make certain you do not leave the room during the charge cycle. Over-discharged lithium batteries are far more likely to do Horrible Things than properly treated ones.

Really, this one is your decision.

 

[awj03130]

Thank you MorpheusPA.

That was as consice, neutral and informative an answer I could've hoped for!

Its back on the charger and is charging with me staring at it from across the room lol. Out of curiosity, do you think a stainless steel kitchen sink would hold up to a battery venting? Because there's one right behind it in event of emergency lol.

Honestly, I am a very routine sub-ohm builder and I build low. As you can see from the picture, I had already put the "Do not use" label on it until I happened to see that on the xtar website.

If it charges, great. I'll use it for higher sub-ohm builds and keep the sticker on it so I don't go lower than, say .5 ohms (total uneducated guess there, feel fr3 to help me out). If not, oh well, but it appears to be charging.

P.s. when I checked the temp of my battery, it seemed like the charger was generating quite a lot of static. I actually zapped myself on the battery and thought my life had ended. When I got up to check again, static was less but still there. Thoughts?

Pray for me.

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[awj03130]

By the way, what do I do in case the battery starts to vent? And will it swell before venting?

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[MorpheusPA]

Thank you MorpheusPA.

That was as consice, neutral and informative an answer I could've hoped for!

Its back on the charger and is charging with me staring at it from across the room lol. Out of curiosity, do you think a stainless steel kitchen sink would hold up to a battery venting? Because there's one right behind it in event of emergency lol.

Good. I'd be tempted to charge it IN the sink, with the water turned to the other basin to avoid any mishaps.

We should note that when it comes to batteries, I'm a bit of a Nervous Nellie. Most people would have told you to recharge that battery and not worry about it. They're mostly right, vicious blowouts are rare even at 2.7 volts, but why take chances? I'm not a fan of doing so.

Honestly, I am a very routine sub-ohm builder and I build low. As you can see from the picture, I had already put the "Do not use" label on it until I happened to see that on the xtar website.

Batteries CAN be restored from low voltage conditions, but critical failure becomes more likely. Eventually, dendrites would form from cathode to anode, creating a hard short. That tends to happen on badly abused batteries.

If it charges, great. I'll use it for higher sub-ohm builds and keep the sticker on it so I don't go lower than, say .5 ohms (total uneducated guess there, feel fr3 to help me out). If not, oh well, but it appears to be charging.

From the photo, the charger is up to the job, admirably. I'm not sure what the absolute low voltage cutoff is for that charger, but the ad actually shows one at 1.50 V. That would be direct to recycle in this household.

P.s. when I checked the temp of my battery, it seemed like the charger was generating quite a lot of static. I actually zapped myself on the battery and thought my life had ended. When I got up to check again, static was less but still there. Thoughts?

Is the weather particularly dry today there? I seriously doubt there's any connection, but I suppose a static charge could build up on the casing. Regardless, it's not anything I'd worry about unless you touch the battery charger and get shocked every time. That would indicate a short to the case, which I'm sure is fire-resistant plastic and not metal anyway (metal cases may not even be legal any longer, I'm not sure).

Pray for me.

Ha! The Great and Powerful Voltar is the god of batteries. Sacrifice a few Duracell to his name and you should be just fine...

 

[r77r7r]

Touch the sink before you touch the charger to draw off the static discharge.........

 

[MorpheusPA]

By the way, what do I do in case the battery starts to vent? And will it swell before venting?

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Panic.

But seriously, there's not much you can do. Try to get it into the sink (I'd suggest using the power cord to move the whole charger into the sink). Unplug the charger. Wait for it to subside. Open the windows to dissipate the vapors (they're not toxic in those concentrations, but will smell terrible and aren't exactly what I'd want to be breathing).

Warning...little to none. The reaction is happening far faster than a human can perceive. Sometimes the battery gets hot beforehand, sometimes it's a big surprise. Sometimes you hear the gas starting to vent. More often, no.

 

[awj03130]

R77r7r did just that the third time, just like a car at the gas station

MorpheusPA - abused batteries make me very nervous too... I've never encountered an over-discharge situation before, but to be honest, the MNKE 26650 had so many mAh and gave off the juice with such stability that it was hard to notice the performance drop. It was working fine and then it wasn't! Waaaaaayyyyy different than the vtc4's I have that give great power and then drop off a cliff!

As for the dendrite formation (I appreciate using the technical terms, I feel like I trust people better when I hear more educated opinions), when you say eventually, do you mean if continuously over-discharged or just with normal use after an over-discharge situation like mine?

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[MorpheusPA]

R77r7r did just that the third time, just like a car at the gas station

MorpheusPA - abused batteries make me very nervous too... I've never encountered an over-discharge situation before, but to be honest, the MNKE 26650 had so many mAh and gave off the juice with such stability that it was hard to notice the performance drop. It was working fine and then it wasn't! Waaaaaayyyyy different than the vtc4's I have that give great power and then drop off a cliff!

So even at reduced voltage (and very close to being completely empty) they perform well. Good to know, actually, as some batteries lose punch when they're on the low side.

As for the dendrite formation (I appreciate using the technical terms, I feel like I trust people better when I hear more educated opinions), when you say eventually, do you mean if continuously over-discharged or just with normal use after an over-discharge situation like mine?

Technically, dendrite formation happens every time the battery is discharged, but functionally it doesn't matter very much. Even a hard short of a very fine dendrite isn't an issue as it'll fall apart as soon as charge or discharge is applied. You have to severely over-discharge a battery for that to be a risk, and it's more of a risk if you leave it there for any length of time. Like crystals, dendrites grow.

Since you specified it was yesterday, I didn't bring it up. Too much over 24 hours and again, I'd tell you to discard the thing even though I know 2.7 isn't a hyper-severe discharge.

Eventually, a severely overworked battery (which describes about a third of my battery collection at the moment) might die due to that--but more often they die simply because the dissolution and reformation of structure at the cathodes and anodes wears away at the structure and they just won't take a charge any longer. Since my overworked batteries are stored at 3.7 V rested charge if they have any storage time at all, dendrite formation isn't a concern.

Optimally, we'd like all of our batteries to last a long time, perform well, and die gracefully when the time comes by simply losing too much capacity to make it worth our while to use them. Avoid over-discharging, never store too far off 3.7 V for "long" periods (short term storage higher or lower is just fine, but never store at no charge), charge gently, and don't drop them and they're almost assured to perform optimally.

 

[keonee]

Thank you MorpheusPA.

That was as consice, neutral and informative an answer I could've hoped for!

Its back on the charger and is charging with me staring at it from across the room lol. Out of curiosity, do you think a stainless steel kitchen sink would hold up to a battery venting? Because there's one right behind it in event of emergency lol.

Honestly, I am a very routine sub-ohm builder and I build low. As you can see from the picture, I had already put the "Do not use" label on it until I happened to see that on the xtar website.

If it charges, great. I'll use it for higher sub-ohm builds and keep the sticker on it so I don't go lower than, say .5 ohms (total uneducated guess there, feel fr3 to help me out). If not, oh well, but it appears to be charging.

P.s. when I checked the temp of my battery, it seemed like the charger was generating quite a lot of static. I actually zapped myself on the battery and thought my life had ended. When I got up to check again, static was less but still there. Thoughts?

Pray for me.

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My understanding when using the Intelligent i4 the same size batteries should be in bays 1 & 3 or 2 & 4.

Good Luck to You.

 

[iowajosh]

Is there a spec sheet for that battery? I google "MNKE 26650" and it tells me max discharge 2.5v in a couple of different places. I haven't seen any batteries that can't go below 3.1? Vapor stuff often cuts off there but flashlights don't.

 

[denali_41]

i am using kicks in several mods ,,my kick usually stops working at the 2.8 to 3.0 range depending on the watt setting

i have been discharging most all of my batts down to 2,8 range and recharging without any problem for well over a year

but feel free to be afraid of your batteries

 

[steel bender]

Please only take this with a grain of salt, because I don't actually know, but I thought the mah rating of the 26650 batts was considered overated, because they are supposed to be able to discharge down to like 2 or maybe it was 2.5 voltsor something. Basically much lower than we normally use for our purposes anyway?

 

[gofastman]

By the way, what do I do in case the battery starts to vent? And will it swell before venting?

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Throw a bucket of sand on it and evacuate the area very quickly!

 

[roadie]

My understanding when using the Intelligent i4 the same size batteries should be in bays 1 & 3 or 2 & 4.

Good Luck to You.

I'm curious where you heard that. I routinely charge my 18650 and 18350 on any available slot. That info wasn't in the manual that came with my i4. Will be changing my habits if need be.

Edit:

Actually, I found this in another post on an i4 review for Version 2:

"As explained in the manual, while the charger has four bays, it actually only has two independent channels. If you want to charge two cells independently of each other (i.e., each charged at the full 750mA current the unit is capable of), you need to place the cells in bays #1 & #2, #2 & #3, #1 & #4, or #3 & #4.

If you place the cells in the paired bays #1 & #3, or #2 & #4, the charging current will be split between the cells. Rather than just cutting in half (i.e., 375mA per bay), the current remains at 750mA for each bay – but it alternates charging by cycling off/on once every second for each battery. This effectively results in the same thing, but the cell is actually being charged at 750mA for a 1sec on, 1sec off, cycle. "

 

[awj03130]

I'm curious where you heard that. I routinely charge my 18650 and 18350 on any available slot. That info wasn't in the manual that came with my i4. Will be changing my habits if need be.

Edit:

Actually, I found this in another post on an i4 review for Version 2:

"As explained in the manual, while the charger has four bays, it actually only has two independent channels. If you want to charge two cells independently of each other (i.e., each charged at the full 750mA current the unit is capable of), you need to place the cells in bays #1 & #2, #2 & #3, #1 & #4, or #3 & #4.

If you place the cells in the paired bays #1 & #3, or #2 & #4, the charging current will be split between the cells. Rather than just cutting in half (i.e., 375mA per bay), the current remains at 750mA for each bay – but it alternates charging by cycling off/on once every second for each battery. This effectively results in the same thing, but the cell is actually being charged at 750mA for a 1sec on, 1sec off, cycle. "

Good info. Thx! Morpheus, Thx as always! To all others, thanks as well!

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[erawtik]

Well I have the xtar and I had my batteries around 2.4 and the xtar charged them back np. I don't do it on purpose just happened, I usally charge around 3.4. I'm using eh 30 amps, just picked up a sony to cycle in the mix. Oh and the xtar is suppose to blink a certain way for over discharged batts and it never has yet so I must not of taken it that low yet.