explosion when charging li-ion cell, Universal Smart charger set on wrong voltage

andrewwynn

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charging an M6-R pack is no safer than charging an HDM6 pack. It's hogwash to say an M6R is 'much safer'.. yeah if you shoot a bullet through it maybe... there is no basis in fact with that statement, just another unsupported jab against me.

I just posted exactly what i see from this example.. an unmonitored 14500 charged to double voltage did not hurt somebody, it did not start a fire, though it did melt some plastic carpet.. a 'worst case scenario' for this particular cell and it was not actually all that dangerous. Sure, scary and somewhat dangerous.

Just how is pointing out that in spite of a worst-case scenario.. tantamount to what happened was 'just very scary'. Ask Norm if my assessment was far off base or not.. though he did say 'it might burn down the house'... i believe the gist of the story was 'dodged a bullet, that was a messy scare'..

HDM6 packs use individually protected and balanced across the rows cells. It is easy to charge them balanced if you have the right charger and wish to do so. it is not unsafe by any stretch of the imagination to series charge the HDM6 pack.. eventually when the pack would get enough misbalanced or cells begin to die.. it just won't charge.. or if it does charge it'll have greatly reduced capacity where it can than be easily disassembled and new cells put in.

show me an actual example, not a forum that might once in a while talk about one and we'll discuss it.. the LION and LIPO disasters i've researched in RC world have like in the flashlight world been a case of operator error or some major non-battery defect (like a a short external to the bat. pack starting a fire)).. if you don't over discharge your cells (most likely the instigator of any LION problem).. and don't try to over charge them either with badly unbalanced cells or with the wrong charger setting.. i've yet to see a single example of a catastrophic event with LION and i've accidentally tried myself to cause such a disaster with nothing 'catastrophic' happening. If you are aware of an actual example that is not operator error or non-battery related defect i'd love to see it.

-awr
 

LuxLuthor

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mdocod said:
I'm just saying- the way people are frieking out about this charger... sounds like someone pointing the finger at mcdonalds for burning themselves on the coffee... Like the world is supposed to lay forth a safe path with no possible misadventures, and if ANYTHING happens SUE SUE SUE!!!

I'd be scared to sell a toothpick to the common public without a release form these days....

This is all about educating people, not suing them. You can take every lawyer in the world, and send them to the moon for all I care. To use your gasoline analogy as a comparison to the Lithium battery fire danger. If you took gasoline and a lighter to an Australian Aboriginee tribe who never heard about it, would you just set them on a table and wish them well?

The topic is about people being educated & warned, not about trying to find someone to sue. There was no instruction or warning given with these Alin chargers.
 

andrewwynn

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lux lux lux.. you are an avid flashaholic with a collection worth more than many people's cars, it's tough to believe you didn't do the research about LION batteries when you are very very thorough about how you go about buying lights and such.

It's simply amazing that you didn't stumble into the myriad warnings about how LION batteries work and the possible risks associated with them... regardless.. i wouldn't have set you up with a 'dangerous' light and you don't have one. it is not dangerous to use 4x14500 cells in series and charge them in series if a reasonable amount of common sense is applied...

I'm very glad you found out albeit very very late in the game considering your collection of lights about the critical nature of charging cells to the right voltage..

The concept obviously should be more noticeable for newbies to find out just how important it is.. i will point out if you buy the charger from batteryspace they do warn that the batteries should be used with a prot. circuit to avoid accident.

My point about the lack of danger in your case is this... it will be almost impossible to create the scenario you just described it borderlines on 'myth'... i just don't see any reasonable way to get there... by the time you can have cells mismatched so badly as to cause a charging problem the operational performance would be so bad (i.e. less than 1 minute run time) you would know to replace the cells etc.. This is my primary point about this situation. There are not going to 'one cell popping after another with 14500 cells.. i would love to see somebody try.. the first one will blow the pack apart and the rest will maybe leak from the damage.. that's my theory.

The LION can start on fire.. NIMH just blows the guts everywhere, that's why LION and LIPO are more hazardous.. What i've been saying and will continue to say.. these smaller LION cells are not in the same league as a pack of 6 or 8 18650s packed tightly together where they can cascade fire when shot with a bullet or through some other external-to-the-cell malfunction like the dell laptop battery.

You came off sounding like you 'have a bomb' in your flashlight.. it is not remotely that dangerous. AW does sell protected cells that are 14500 and 14670 size.. they probably don't have the power to run the 1166 lamp ... there are some trade-offs.. the protected cells do not fix the balancing problem they just are helpful to make it more noticeable when it happens.

Balance out the charge on your pack once in a while and you are not going to have a major problem.. don't discharge completely and keep the pack charged and you are less likely to have a problem.

If you or anybody can come up with an actual example of a series LION pack that hasn't been abused and is damaged other than by operator error i would seriously like to see it, i've not found any yet.

-awr
 

cy

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more absolute GARBAGE!!!

how can anyone even imply charging a multi-cell li-ion pack carries the same risk as charging a multi-cell NMH pack?

cut your Bull Sh*t! it simply will not fly.

it's the danger during charging, NOT over discharging which protection circuits should take care of. even if high temp cut-off occurs during charging. so what if 600 milliamps or so is stopped? if thermal run-away has already occurred. that will not stop venting with flames.

these dangers are not just about your HDM6 packs alone. this goes for charging any multi-cell li-ion packs. the larger the number ... the larger the risks. possible secondary explosion fueled by the original failure.

go watch a few video from RC forums, if you think I'm making this up!!!


andrewwynn said:
charging an M6-R pack is no safer than charging an HDM6 pack. It's hogwash to say an M6R is 'much safer'.. yeah if you shoot a bullet through it maybe... there is no basis in fact with that statement, just another unsupported jab against me.

I just posted exactly what i see from this example.. an unmonitored 14500 charged to double voltage did not hurt somebody, it did not start a fire, though it did melt some plastic carpet.. a 'worst case scenario' for this particular cell and it was not actually all that dangerous. Sure, scary and somewhat dangerous.

Just how is pointing out that in spite of a worst-case scenario.. tantamount to what happened was 'just very scary'. Ask Norm if my assessment was far off base or not.. though he did say 'it might burn down the house'... i believe the gist of the story was 'dodged a bullet, that was a messy scare'..

HDM6 packs use individually protected and balanced across the rows cells. It is easy to charge them balanced if you have the right charger and wish to do so. it is not unsafe by any stretch of the imagination to series charge the HDM6 pack.. eventually when the pack would get enough misbalanced or cells begin to die.. it just won't charge.. or if it does charge it'll have greatly reduced capacity where it can than be easily disassembled and new cells put in.

show me an actual example, not a forum that might once in a while talk about one and we'll discuss it.. the LION and LIPO disasters i've researched in RC world have like in the flashlight world been a case of operator error or some major non-battery defect (like a a short external to the bat. pack starting a fire)).. if you don't over discharge your cells (most likely the instigator of any LION problem).. and don't try to over charge them either with badly unbalanced cells or with the wrong charger setting.. i've yet to see a single example of a catastrophic event with LION and i've accidentally tried myself to cause such a disaster with nothing 'catastrophic' happening. If you are aware of an actual example that is not operator error or non-battery related defect i'd love to see it.

-awr

andrewwynn said:
lux lux lux.. you are an avid flashaholic with a collection worth more than many people's cars, it's tough to believe you didn't do the research about LION batteries when you are very very thorough about how you go about buying lights and such.

It's simply amazing that you didn't stumble into the myriad warnings about how LION batteries work and the possible risks associated with them... regardless.. i wouldn't have set you up with a 'dangerous' light and you don't have one. it is not dangerous to use 4x14500 cells in series and charge them in series if a reasonable amount of common sense is applied...

I'm very glad you found out albeit very very late in the game considering your collection of lights about the critical nature of charging cells to the right voltage..

The concept obviously should be more noticeable for newbies to find out just how important it is.. i will point out if you buy the charger from batteryspace they do warn that the batteries should be used with a prot. circuit to avoid accident.

My point about the lack of danger in your case is this... it will be almost impossible to create the scenario you just described it borderlines on 'myth'... i just don't see any reasonable way to get there... by the time you can have cells mismatched so badly as to cause a charging problem the operational performance would be so bad (i.e. less than 1 minute run time) you would know to replace the cells etc.. This is my primary point about this situation. There are not going to 'one cell popping after another with 14500 cells.. i would love to see somebody try.. the first one will blow the pack apart and the rest will maybe leak from the damage.. that's my theory.

The LION can start on fire.. NIMH just blows the guts everywhere, that's why LION and LIPO are more hazardous.. What i've been saying and will continue to say.. these smaller LION cells are not in the same league as a pack of 6 or 8 18650s packed tightly together where they can cascade fire when shot with a bullet or through some other external-to-the-cell malfunction like the dell laptop battery.

You came off sounding like you 'have a bomb' in your flashlight.. it is not remotely that dangerous. AW does sell protected cells that are 14500 and 14670 size.. they probably don't have the power to run the 1166 lamp ... there are some trade-offs.. the protected cells do not fix the balancing problem they just are helpful to make it more noticeable when it happens.

Balance out the charge on your pack once in a while and you are not going to have a major problem.. don't discharge completely and keep the pack charged and you are less likely to have a problem.

If you or anybody can come up with an actual example of a series LION pack that hasn't been abused and is damaged other than by operator error i would seriously like to see it, i've not found any yet.

-awr
 
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LuxLuthor

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Andrew, did you even bother to read even the first couple pages of that "How to contain fire/smoke" thread I just linked ? You are ignoring a lot of people who had cells blow up and cause major fires who were not doing something wrong.

There are also all the issues of Lithium cells in laptops, being shipped on planes, and assuming that adequate testing has been done on the Li-Ion batteries (protected and unprotected) that we use in our lights.

Do you know for a fact what would happen to a Li-Ion protected battery that rolled off a table and landed on the floor if the PCB corner end struck the ground? I have had at least 10 roll off my desk onto a wood floor. If you don't know that the various extreme situations are safe, then dismissing this danger and having it be no big deal to warn people not to charge them on a wood dining room table, unattended is irresponsible.

Most Li-Ion users in this forum have no awareness about cell balancing in packs. I seriously doubt that most have any idea how important it is to select the right number of cells with that lame-*** designed switch on Alin's charger...with the miniture text, and lack of a clear slot indication.

What if Norm had had some papers near his charger? You assume they would not have caught fire? To dismiss his situation as relatively harmless is just totally ignorant.
 
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mdocod said:
I'm just saying- the way people are frieking out about this charger... sounds like someone pointing the finger at mcdonalds for burning themselves on the coffee... Like the world is supposed to lay forth a safe path with no possible misadventures, and if ANYTHING happens SUE SUE SUE!!!

I'd be scared to sell a toothpick to the common public without a release form these days....

Tort laws are often justified and most are not dumb like "hammering your finger may result in injury" or "stabbing yourself with a box cutter maybe harmful". I think they are a positive thing in society.

Manufacturers have a duty of care to a varying degree of standard of care.

A combination of foreseeable, likely and preventable affects the determination of liability.

Microwave exposure is not good for you. If they put "don't open the door while the microwave open is in use" and everyone obeyed it, it's all good.

Instead, they put two interlocks. One that would prevent the oven from working and other that permanently disables the appliance if the interlock is tampered with.

Lacking tort law, the manufacturer would get away with "well too bad, you should've known better than opening the door while it's operating"
 

SilverFox

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In spite of AWR's efforts to dismiss the severity of the problems that you can encounter when charging Li-Ion cells in series, I think we should take a closer look at this.

LuxLuthor pulled some cells out and measured their voltages. They were at

3.950
3.240
3.890
3.410

If we hook these four cells in series and charge them as a 4S pack, the charger will terminate the charge at 16.800 volts. Hooking these cells in series will give us 14.490 volts, so the charger is going to raise the total pack voltage 2.370 volts.

That means that each cell will increase 0.578 volts.

So the cells with this 0.578 volts added will now be at

3.950 + 0.578 = 4.528 volts
3.240 + 0.578 = 3.818 volts
3.890 + 0.578 = 4.468 volts
3.410 + 0.578 = 3.989 volts

Venting with flame occurs right around 4.5 volts, give or take a little.

This means that 2 of the 4 cells would be at risk of "rapid disassembly."

AWR seems to indicate that this is acceptable, and no big deal. I don't agree with him.

I also believe that the dangers with NiMh and NiCd packs are very real. These cells, as they approach thermal runaway, have an internal pressure of 200 - 300 psi. When the top blows off, it can do quite a bit of damage. However, the electrolyte that spills out is not flammable.

A Li-Ion cell will not build up to a similar pressure, but the electrolyte is flammable.

It is my opinion that we should heed cautions, and take precautions to make sure the flammable electrolyte stays within the cells. I also believe that the non flammable electrolyte of Nickel cells should stay within the cells and not make a mess in our charging area.

AWR, I believe people need to error on the side of caution. I always ask myself that if someone followed my advice and something drastic happened, how would I feel. Suppose someone's child was hurt because the dad thought that the danger with Li-Ion cells is overstated. I don't want to live with that possibility. I am sure you don't either.

I am sorry that you have been unable to start a fire while overcharging a Li-Ion cell. It is actually very easy to do, but you are correct in that it doesn't happen each and every time. When it does happen, it is very impressive, and you gain resolve to never let it happen outside of a controlled area. It reminds me of setting off a road flare, except it doesn't burn as long. Not something I want to do in my house.

Lithium chemistry offers high energy density, however there are some dangers associated with it. I believe people who use this chemistry need to read up on it and understand the dangers and what they can do to minimize them.

The RC people have a sticky with over 100 incidents of problems with their Li-Po cells. The Li-Po cells are more fragile than Li-Ion cells, but if you damage a Li-Ion cell, you can experience similar results.

It is interesting to note that most of these incidents happen during charging. It is also interesting to note that since they started using cell balancers, the occurrence of incidents has dropped off.

I think we need to understand that Li-Ion cells need to be treated with respect, especially while charging them.

Tom
 

andrewwynn

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The 'adding of voltage' does not really work that way Tom, you should know that of anybody.. charge that pack up fully and the cells will get closer in voltage absolutely guaranteed unless one fails short or something. Not likely to happen from a pack that is already clearly mostly charged.. When the pack is loaded on a charger those cells will get much closer together and none of them are going to get to 4.5V or there would have been a lot more cases of people with 4S1P cells with disastrous results.

I don't find 'acceptable' a dangerous solution.. i don't consider 4S1P 14500s that are charged in series and discharged with a pack shutdown dangerous and i find this *particular* example acceptable.. i would not series charge 4S1P of 18650s.. and LiON Ds i charge always 1 at a time.. i use a very similar thought-train about feeling bad if somebody follows my advice .. I actually use this rule: would i let my mom/grandma use this solution and the answer is yes.. and yes i'd tell them they should check the voltages periodically before charging .. just as if *i* had sold lux his cells i'd have told him as well.

I absolutely agree that there should be point-by-point directions about series charging to avoid the problem... I was only saying that there was a sense being exhibited here that there was something inherently bomb-like dangerous from series charging and mis-matched cells..

the 'RC' world is famous for drastically abusing cells, especially LION, it is of no surprise to me there would be more faults there.. but i still haven't seen an example that is similar to what is described in this thread as super-extra-mega-dangerous.

I'm NOT saying that LION cells can be care-free charged.. I *am* saying they should be parallel charged or at the very least monitored for like voltages before and after charging at least periodically.. (every 5th-10th charge is probably just fine for 14500s).

So.. there is theory being presented as fact once again and that's what i have a problem with:

silverfox said:
Venting with flame occurs right around 4.5 volts, give or take a little.

This means that 2 of the 4 cells would be at risk of "rapid disassembly."

Put some cells with no-load voltage of those 4 voltage readings on a charger in-series.. they will get FAR closer together.. and though i wouldn't be surprised if a cell gets over 4.3V i would be extreeemly surprised if one gets over 4.4V.. this is my theory.. but history backs me as being more accurate because i've never heard of a SINGLE event of 4S1P 14500s ever venting from charging at 1/2A.. correct me if i'm wrong.

cy.. for YOUR information all the lion pcbs that i would ever use or buy have over voltage protection or they are worthless. if you have cells or pcbs without them you have a crappy supplier.

lux.. i'm not saying there wasn't a 'chance' for the Norm event to have caused a fire.. i am saying the FACT.. that it did not. i'm also saying that i'm aware of at least 1/2 a dozen similar events that also like the Norm event.. melted something, spat black goo on something scared the crap out of somebody and that was the endofit. I'm not dismissing it as 'not dangerous'.. i'm saying that it should be handled with the proper amount of caution.. and i'm also saying.. the 'RC' world with 4AH cells and a 600mAH cell is not the same league in any way shape or form, not to mention all the talk of LIPO packs which also has little to do with the little single AA cell shown in this thread.

back to cy.. every cell in the HDM6 is an individually protected cell.. protected against shorts against over discharge and over charge. I wouldn't have it any other way, it would be foolish to sell a pack without such protection because it's way to easy to have a charger set to the wrong switch setting and cause explosions.

I believe there should be a very obvious 'read first' section for the risks and rewards of LION in any 'battery forum' and it of course should espouse the notion of how to best care for a series pack of LION.. starting with.. 'if you are a newbie, just plain don't'. lux.. you want to have it both ways.. being a 'flashaholic' when it comes to owning the myriad lights but being a 'newbie' after having them for quite some time.. you did bad research to not know well in advance of having LiON series-powered lights and not know about balanced charging, how you got that far is a mystery but at least now you do know. I think a concise warning explaining the how to's of LION and especially regarding discharge and charging would be a great idea and should as i mentioned be considered a 'must have'.

-awr
 

LuxLuthor

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Andrew, I just don't think your assumption that charging Li-Ion cells in S4-P1 or S4-P2 will not result in a fire....because you have not heard of such an event is smart in the face of so many examples in the RC LiPo world. We know it has happened with free cells on airplanes. We know it happens with laptop packs that are not abused like the RC users. We know it happens with the non-rechargeable 123's. We know there are strict warnings given about maximum charging voltage cutoffs. We know chargers have cutoffs typically at 4.2V.

All of that suggests a stronger case for the real danger, than your speculative arguments that it is overstated and overblown.

I don't think you can be sure of your voltages coming closer into balance response to SilverFox unless it is specifically tested. The cells in a FM pack are touching the other cells on two sides. You honestly don't think there would be enough heat/damage from one cell exploding/catching fire to cascade the other three, while contained inside of a Maglite tube? I do.

Now, about my own failure to find out about the Lithium charging guidelines. Guilty as charged. I again remind you, that NOTHING was stated as a warning on AW's GB thread, nothing on Alin's charger GB, nor the plain box, nor in AW's DSD charger GB, nor the DSD's plain box, nor the Pila site where I chose the battery sizes I wanted, nor in the box with the Pila charger, nothing in any of FiveMega's GB threads that used Li-Ions, and linked Alin's charger, nor from you when I got the unprotected 4S Mag66, nor a warning of a danger of fire or explosions with my cell phone or laptop battery.

I heard about the Sony Laptop battery recall, but figured it was totally related to a mis-wired battery holder, or some bizarre manufacturing defect. It never occurred to me that there might be an inherant risk in the entire Lithium battery technology that was not present with Lead Acid, NiCad, or NiMH.

I also never thought that Maglite mods, Li-Ion batteries, and Lithium chargers would be sold here without a clear, obvious warning being stated in the GB threads that would have caught my attention. I guarantee I am not the only one who has missed this danger, and how to use Lithium batteries safely.
 

cy

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yet more GARBAGE!!!

I suppose you now will claim your li-ion cells are special and different from anyone else's.

Your bull sh*t will not fly here!

andrewwynn said:
cy.. for YOUR information all the lion pcbs that i would ever use or buy have over voltage protection or they are worthless. if you have cells or pcbs without them you have a crappy supplier.

~back to cy.. every cell in the HDM6 is an individually protected cell.. protected against shorts against over discharge and over charge. I wouldn't have it any other way, it would be foolish to sell a pack without such protection because it's way to easy to have a charger set to the wrong switch setting and cause explosions.
-awr

andrewwynn said:
The 'adding of voltage' does not really work that way Tom, you should know that of anybody.. charge that pack up fully and the cells will get closer in voltage absolutely guaranteed unless one fails short or something. Not likely to happen from a pack that is already clearly mostly charged.. When the pack is loaded on a charger those cells will get much closer together and none of them are going to get to 4.5V or there would have been a lot more cases of people with 4S1P cells with disastrous results.

I don't find 'acceptable' a dangerous solution.. i don't consider 4S1P 14500s that are charged in series and discharged with a pack shutdown dangerous and i find this *particular* example acceptable.. i would not series charge 4S1P of 18650s.. and LiON Ds i charge always 1 at a time.. i use a very similar thought-train about feeling bad if somebody follows my advice .. I actually use this rule: would i let my mom/grandma use this solution and the answer is yes.. and yes i'd tell them they should check the voltages periodically before charging .. just as if *i* had sold lux his cells i'd have told him as well.

I absolutely agree that there should be point-by-point directions about series charging to avoid the problem... I was only saying that there was a sense being exhibited here that there was something inherently bomb-like dangerous from series charging and mis-matched cells..

the 'RC' world is famous for drastically abusing cells, especially LION, it is of no surprise to me there would be more faults there.. but i still haven't seen an example that is similar to what is described in this thread as super-extra-mega-dangerous.

I'm NOT saying that LION cells can be care-free charged.. I *am* saying they should be parallel charged or at the very least monitored for like voltages before and after charging at least periodically.. (every 5th-10th charge is probably just fine for 14500s).

So.. there is theory being presented as fact once again and that's what i have a problem with:



Put some cells with no-load voltage of those 4 voltage readings on a charger in-series.. they will get FAR closer together.. and though i wouldn't be surprised if a cell gets over 4.3V i would be extreeemly surprised if one gets over 4.4V.. this is my theory.. but history backs me as being more accurate because i've never heard of a SINGLE event of 4S1P 14500s ever venting from charging at 1/2A.. correct me if i'm wrong.

cy.. for YOUR information all the lion pcbs that i would ever use or buy have over voltage protection or they are worthless. if you have cells or pcbs without them you have a crappy supplier.

lux.. i'm not saying there wasn't a 'chance' for the Norm event to have caused a fire.. i am saying the FACT.. that it did not. i'm also saying that i'm aware of at least 1/2 a dozen similar events that also like the Norm event.. melted something, spat black goo on something scared the crap out of somebody and that was the endofit. I'm not dismissing it as 'not dangerous'.. i'm saying that it should be handled with the proper amount of caution.. and i'm also saying.. the 'RC' world with 4AH cells and a 600mAH cell is not the same league in any way shape or form, not to mention all the talk of LIPO packs which also has little to do with the little single AA cell shown in this thread.

back to cy.. every cell in the HDM6 is an individually protected cell.. protected against shorts against over discharge and over charge. I wouldn't have it any other way, it would be foolish to sell a pack without such protection because it's way to easy to have a charger set to the wrong switch setting and cause explosions.

I believe there should be a very obvious 'read first' section for the risks and rewards of LION in any 'battery forum' and it of course should espouse the notion of how to best care for a series pack of LION.. starting with.. 'if you are a newbie, just plain don't'. lux.. you want to have it both ways.. being a 'flashaholic' when it comes to owning the myriad lights but being a 'newbie' after having them for quite some time.. you did bad research to not know well in advance of having LiON series-powered lights and not know about balanced charging, how you got that far is a mystery but at least now you do know. I think a concise warning explaining the how to's of LION and especially regarding discharge and charging would be a great idea and should as i mentioned be considered a 'must have'.

-awr
 
Last edited:

SilverFox

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Hello Andrew,

I am sorry if you don't understand how Li-Ion cells work. The example I gave is exactly how it works. Li-Ion cells have no ability to withstand an overcharge and can not be balanced through peak charging.

When Li-Ion cells are completely discharged the cell to cell imbalance will be greater, but if you look at the example you will see that some of the cells were nearly fully charged. These cells have nowhere to go but up to a higher voltage.

The RC people do push the limits, but there is a lot of them that work within the limits too. When these people report their packs catching on fire, I take notice. When they report that their packs have gone out of balance and the packs puff and blow while charging, it is enough evidence for me.

Your theory is wrong. There are a whole bunch of people with burned up trailers, shops, cars, and houses to prove that it is wrong.

If you tell others that Li-Ion cells will self balance, you are wrong and this is a very dangerous thing to do. People listening to your theory will end up having problems, which may include fire damage.

If you want to play with fire, please do so by yourself. Please don't bring unsafe and unsound charging methods forward and encourage others to follow them.

Tom
 

Icebreak

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andrewwynn said:
i wouldn't have set you up with a 'dangerous' light and you don't have one. it is not dangerous to use 4x14500 cells in series and charge them in series if a reasonable amount of common sense is applied...

Well maybe it's prespective. There have been reports of your hotdriver frying in high current applications. These were sold by you and known by you what configurations they would be used in. It is dangerous to use unprotected Li-Ions in series. With knowledge, care and prudency that danger can be reduced. It's possible that the danger is increased when using them in conjunction with a driver that can fail. A fried driver in between a hot wire and a stack of unprotected Li-ons is not good. Common sense.
 

LED61

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So Tom, what do we BarnBurner owners do about our (12 in series I believe) rechargeable Li ion pack ? What could develop an unstable situation and how would we know if the cells are becoming unbalanced and at some point some will overcharge ?
 

LuxLuthor

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LED61 said:
So Tom, what do we BarnBurner owners do about our (12 in series I believe) rechargeable Li ion pack ? What could develop an unstable situation and how would we know if the cells are becoming unbalanced and at some point some will overcharge ?

I did not see that the battery pack has individual cell taps to balance each of the cells, so this is a good question.

The other problem that was discovered on the first generation XeRay 50W from that GB is the PCB has a draining effect on the cells that reportedly could take the cells low enough that the pack would be ruined. I'm not sure what was actually happening to the individual cells in that instance, nor what would happen if you then tried to charge them afterwards. I'll send a PM to Dan about these posts to see if he knows what is going on with those batteries.
 

LuxLuthor

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I made this post at the All-Battery.com forum where they have this diagram in their FAQ's. I think this might work.

pack_wiring_taps_conv.jpg
 
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SilverFox

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Hello Alberto,

The BarnBurner uses 12 cells in a 4S3P configuration. I spoke with them and they have a circuit that monitors the pack, but I was unable to get any more details.

If you have access to that pack, you may be able to probe around and get individual cell voltages. It is best to do this with a fully charged pack.

If you are concerned, charge it outside away from combustible materials.

Tom
 

LuxLuthor

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I made Dan aware of this issue, and I think it now "has his attention." I did verify with one of my extra BB packs that there is no individual cell leads or balancing going on. There is a PCB, but I don't know what it is doing. I suspect these are unprotected cells, and the PCB is giving some level of pack protection...but it is now in a safety issue category for me.

Damn it! I wish I hadn't learned all this stuff sometimes.
 
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