Question on weird battery drain: Malkoff M61w and AW 18650

Hi gurus,

I had an M61w installed in a Surefire 6P bored to accept 18650. I am running an AW18650 2200 mah since I had quite a lot of 2200 mah and don't know what to do with them. It was working fine just a few days ago but last night I was surprised to see the light not working at all and so I did a battery check only to realize that the battery has been drained to 0.005 volt.

I can't be too certain if I did really switch off the light before placing it bezel down on my wooden shelf. I usually have the habit to check and ensure that the lights off, but I may have missed out on that.

So here's my questions...

Is it possible for a protected 18650 to drain down to such minuscule amount like 0.005 volt? Is the battery spoilt, and if it's not, would this low drain damage the battery at all? Last night I placed it into the Nitecore i4 Intellicharger and it has been 9 hours since and still charging.

Do you guys think that I left my light on when I placed it bezel down on the shelf? If I did, I don't see any damage on the shelf nor the finishing that was supposedly created by the heat buildup. Would there be enough heat generated by the M61w to burn or bubble the finishing of the shelf at least?

Worst case scenario. Was there a slight short circuit somewhere that resulted in the parasitic drain of the battery, or is the battery age the cause of it? After all, the battery is about 4 or 5 years old and have yet to see much action. I did however use it once in a couple of months and charge it up.

I understand that the M61w was designed to taper down its output when the battery is weak, but does it have a protection cutoff when the battery is too weak?

Thank you guys!

Are you saying your lithium ion drained to that voltage? You shouldn't try to charge a li-ion that has gone below 2.7v ever or it could easily vent. Since it's a protected 18650 it should never charge at all below the voltage the circuit kicks in at (probably 2.7v but not 100% on that could be a couple tenths voltage lower). Any li-ion that goes below that should be disposed of IMO. With protected batteries the protection circuit might have kicked in and you might be getting the low voltage reading because of that. Are you checking the voltage with a meter?

Yes I am checking the battery with a DMM although I am not too sure if the low voltage reading has anything to do with the protection circuitry kicking in. Being silly and ignorant, I placed it in the charger last night but thankfully nothing has happened as yet. Maybe the low readout has more to do with the protection circuitry than an actual low voltage readout. I will probably check the battery's voltage again when I get home. Pulled it out of the charger when I went out just to be safe and sure. I am just curious what could have been the cause of the low voltage readout.

I would either check it with a different meter or use that meter with a different battery just to make sure it's not the meter. It could have just drained to it's low volt protection setting..once it goes below that as far as I know the battery is junk.

Like you posted you could have left it on but who knows..if it happens with another battery in the light without the light on you will know it has to do with the light itself..just don't use an unprotected battery in the light if you think there might be an issue with it and it should be pretty safe.

Also could just be a bad battery itself as they fail sometimes. Another reason might be if it was dropped hard that can damage lithium ion batteries. Anytime a lithium ion battery is dropped hard at all it should be tested for changes...

It sounds like the protection kicked in, and you need to jump start the battery with a higher voltage to get the protection unit to activate again. Ask in the battery section on how to jump start it.

I have had AW 18650 protected battery protection kick in before. All I did was put it in my pila charger and it charged back to around 4.15.

Ok guys, I think it is a case of the protection kicking in on the battery. I had earlier charged it up with no issues and the battery measured 4.186 volts. I may have accidentally depleted the battery, probably leaving it on and unattended. Just real curious how it could have happened without me knowing it.

FlashKat said:

It sounds like the protection kicked in, and you need to jump start the battery with a higher voltage to get the protection unit to activate again. Ask in the battery section on how to jump start it.

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I wouldn't suggest doing this as the batteries are pretty inexpensive usually and a lot less money than if you burn yourself or something else if it vented..besides who knows for sure why the protection kicked in could be a short and if you jumped good chance it would vent if there's any damage...

I see you have been around a long time, and you are an expert!! If Pjandyho wants to throw away his battery, then he may do that by choice. I was only suggesting. Come to think of it rechargeable batteries are considered dangerous, so everyone should stop using them for your safety.

ChrispyCritter said:

I wouldn't suggest doing this as the batteries are pretty inexpensive usually and a lot less money than if you burn yourself or something else if it vented..besides who knows for sure why the protection kicked in could be a short and if you jumped good chance it would vent if there's any damage...

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The light could had been accidentally turned on. That's why I always lock the tail cap when my light is not in use. Glad your battery is OK.

FlashKat said:

I see you have been around a long time, and you are an expert!! If Pjandyho wants to throw away his battery, then he may do that by choice. I was only suggesting. Come to think of it rechargeable batteries are considered dangerous, so everyone should stop using them for your safety.

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Hmm could be I have read and posted about 18650's somewhere else huh. Like 1,256 posts on the E-Cigerette forum..not to mention my 5700+ posts on Sony message boards although that's unrelated..Are these 18650's different than the 18650's they use in E-Cigs? Not saying I'm an expert but if this battery got below a certain voltage it's not safe to recharge it.

It was only my opinion also and I don't claim to be an "expert" but I have repaired over 1,000 game systems and don't know how many computers..even a couple iPhone 4S's.

I've replaced a few dozen engines in cars and other car things including some wiring..anyways I could list a bunch more stuff I've worked on in my 44 years on this planet but I think you get the point.

Sure he might be able to revive the battery but is it really worth the risk?

They make battery chargers that help jump start batteries that trip the protection circuit. There are safe ways to do it. Since you know so much why are you even posting a question on the WF-502B CREE XM-L T6 if you know so much? BTW the WF-502B does not have a built in protection circuit.

ChrispyCritter said:

Hmm could be I have read and posted about 18650's somewhere else huh. Like 1,256 posts on the E-Cigerette forum..not to mention my 5700+ posts on Sony message boards although that's unrelated..Are these 18650's different than the 18650's they use in E-Cigs? Not saying I'm an expert but if this battery got below a certain voltage it's not safe to recharge it.

It was only my opinion also and I don't claim to be an "expert" but I have repaired over 1,000 game systems and don't know how many computers..even a couple iPhone 4S's.

I've replaced a few dozen engines in cars and other car things including some wiring..anyways I could list a bunch more stuff I've worked on in my 44 years on this planet but I think you get the point.

Sure he might be able to revive the battery but is it really worth the risk?

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FlashKat said:

They make battery chargers that help jump start batteries that trip the protection circuit. There are safe ways to do it. Since you know so much why are you even posting a question on the WF-502B CREE XM-L T6 if you know so much? BTW the WF-502B does not have a built in protection circuit.

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"Do not boost lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer. Copper shunts may have formed inside the cells that can lead to a partial or total electrical short. When recharging, such a cell might become unstable, causing excessive heat or showing other anomalies."

How does he know the battery didn't get below that voltage? I think you would to take off the wrapper to test it. Anyways I'm pretty sure it wasn't below said voltage but still there's probably a 10% chance it might overheat and possibly vent.

"A study done by Cadex to examine failed batteries reveals that three out of ten batteries are removed from service due to over-discharge. Furthermore, 90 percent of returned batteries have no fault or can easily be serviced. Lack of test devices at the customer service level is in part to blame for the high exchange rate. Refurbishing batteries saves money and protects the environment."

Nothing wrong with refurbishing batteries but does he know how to do it correctly? I can't assume that so I side with caution.

Since I haven't found "reliable" info on my 2 - WF-502B CREE XM-L T6 and haven't dissembled them yet how would I know if it has circuit protection? I just got my first one the 17th the second today and if they work I won't fix them..at least for now. How do you know it doesn't have it have you dissembled one or more?

Hi ChrispyCritter & FlashKat,

Thank you guys very much. I understand where you guys are coming from and both of you have your reasons. Like I have said, the battery is ok now. I should have been more careful considering that I have been warning people here about correct practices with battery. I took a gamble to charge it up because the battery is protected and I suspected the protection circuitry might have kicked in which resulted in the super low voltage readout although I can't be too sure. That was where I made the mistake in compromising safety for a cheap piece of battery. Should have remembered my advice to others here and practice what I have preached.

Anyway, I ran the battery in my 6P for quite some time last night and it has been good so far.

I didn't see where you posted it had already be recharged. As long as it doesn't get hot, discharge faster than normal and just act weird it's most likely ok..I would monitor it awhile though just to be on the safe side

ChrispyCritter said:

I didn't see where you posted it had already be recharged. As long as it doesn't get hot, discharge faster than normal and just act weird it's most likely ok..I would monitor it awhile though just to be on the safe side

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The post is on #7. Even before I started this thread the battery has been sitting in the charger. It took about 11 hours to charge using the Nitecore i4 charger. That is agonizingly slow. In fact right now I am monitoring the battery by turning it on a few seconds at a time to see if it gets hot but so far it has performed flawlessly. I am thinking that everything should be ok now.

Oh I knew you had it on the charger but didn't know it took a charge. Yeah that is slow usually from 3.5v it only takes a couple hours maybe even with inexpensive China chargers. The charger probably does this on purpose so it is less likely to get hot because of low voltage. So far with the 6 18650 (4 I had around 2 years) they don't even get warm to the touch when charging

ChrispyCritter said:

Oh I knew you had it on the charger but didn't know it took a charge. Yeah that is slow usually from 3.5v it only takes a couple hours maybe even with inexpensive China chargers. The charger probably does this on purpose so it is less likely to get hot because of low voltage. So far with the 6 18650 (4 I had around 2 years) they don't even get warm to the touch when charging

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I guess that is the intention with the i4 charger's design. Used to use an Ultrafire WF-139 quick charger for about 5 years and it was real fast. Maybe I was using protected batteries all those times so the protection circuit of the batteries could have prevented an overcharge. There was once when I placed an IMR 18350 into the WF-139, the final charge showed 4.46 volts and that freaked me out. So that's why I replaced it with the i4 Intellicharger.

Anyway, welcome to CPF! Nice having you around!

Yeah that would scare me anything much over 4.2v would worry me. That's why I test the charger and batteries for awhile after getting any new ones. So far the highest I've seen is 4.22v but that was right off the charger and after a couple mins it was under 4.2v.

I've noticed all my 18650 batteries stay within 4.13-4.19v after charging..surprised me when I didn't use a couple of them for a couple months and they still were right there as I know lithium ion's usually lose some charge with time.

I also refuse to leave batteries charging when I'm not nearby and awake. I suppose if I had to I could charge them in the garage or get a "fire bag"..but I haven't had to as the batteries last long enough I can wait to charge them when I have time. Thank you