18650 Cluster grenades

Joined
Oct 8, 2016
Messages
58
There seems to be a universalignorance of the dangers of Li-ion cells.
Very few people seem to know what internal resistance is. Or why it matters.
Very few people seem to know what thermal runaway is.
Very few people seem to know what short circuit current they are playing with.
Very few people seem to know what happens when an 18650 goes into thermal runaway.
Very few people understand how easily a chain reaction can occur.
Very few people understand how easily a one cell explosion can cause multiple secondary explosions in nearby locations.

If you did, you would never have built giant cluster grenades like you have.
You cannot throw cells of differing internal resistance together and charge them without monitoring.
These are ticking time bombs. What you basically have assembled is a large quantity of skyrockets. Just waiting for one to have its fuse ignite. The first explosion ignites the fuse on many others and spreads them in a 10m radius.

Here I present several videos, showing how easily they explode, how secondary fires begin and the aftermath of these fires / explosions

Quick short circuit causing explosion
Cells in fire turn into flame throwers
Single cell explosion
Aftermath of recycled laptop cells explosion
 

Sean

Member
Joined
Oct 8, 2016
Messages
946
Play another tune please, we've all heard this one before.
 
Joined
Oct 8, 2016
Messages
58
That's funny. This forum is filled with comments like

"1A 4P is 250mA per cell. It's evenly split"

And nobody corrects them. So clearly nobody else here knows it's false. That scares me.

You cannot possibly have respect for the energy you are playing around with if you don't have the first clue about cell characteristics. Playing around with dangerous things you know nothing about is irresponsible. Suggesting to others that they should be equally ignorant is also irresponsible
 

Sean

Member
Joined
Oct 8, 2016
Messages
946
You need to keep reminding us all that it's only you that has the competence and experience to design & build a safe, functional system.
 

3nergE

Member
Joined
Dec 3, 2016
Messages
101
DIYTESLAPOWERWALL said:
There seems to be a universalignorance of the dangers of Li-ion cells.
Very few people seem to know what internal resistance is. Or why it matters.
Very few people seem to know what thermal runaway is.
Very few people seem to know what short circuit current they are playing with.
Very few people seem to know what happens when an 18650 goes into thermal runaway.
Very few people understand how easily a chain reaction can occur.
Very few people understand how easily a one cell explosion can cause multiple secondary explosions in nearby locations.

If you did, you would never have built giant cluster grenades like you have.
You cannot throw cells of differing internal resistance together and charge them without monitoring.
These are ticking time bombs. What you basically have assembled is a large quantity of skyrockets. Just waiting for one to have its fuse ignite. The first explosion ignites the fuse on many others and spreads them in a 10m radius.

Here I present several videos, showing how easily they explode, how secondary fires begin and the aftermath of these fires / explosions

Quick short circuit causing explosion
Cells in fire turn into flame throwers
Single cell explosion
Aftermath of recycled laptop cells explosion

Im calling FUD here too.

Just had two strings go down in a 11s6p pack.
Hadnt noticed, that means cells were getting charged to 5v - AGAIN

No explosion, no issue, the two dead strings still conduct, the existing cells still work fine, no lost capacity.

Its not luck, most cells are well designed and hard to kill.
You need short circuits or fire to kill them.

Seriously ... stop wigging out dude
 

hbpowerwall

Administrator
Staff member
Joined
Oct 7, 2016
Messages
1,907
Ok said:
This bit - YES people need to be told with out a doubt and don't disagree


DIYTESLAPOWERWALLThere seems to be a universalignorance of the dangers of Li-ion cells.
Very few people seem to know what internal resistance is. Or why it matters.
Very few people seem to know what thermal runaway is.
Very few people seem to know what short circuit current they are playing with.
Very few people seem to know what happens when an 18650 goes into thermal runaway.
Very few people understand how easily a chain reaction can occur.
Very few people understand how easily a one cell explosion can cause multiple secondary explosions in nearby locations.

If you did, you would never have built giant cluster grenades like you have.
You cannot throw cells of differing internal resistance together and charge them without monitoring.
These are ticking time bombs. What you basically have assembled is a large quantity of skyrockets. Just waiting for one to have its fuse ignite. The first explosion ignites the fuse on many others and spreads them in a 10m radius.



These examples may as well be pictures of the space shuttle exploding..

Your references - well they kinda lack in any details
- First one was a knock off cell - lets go there all holding hands in the sunshine.
- Second was a laptop placed into a fire
- Third un-named brand, no idea of charger, did the head lamp get wet, was it dropped the list goes on - we'll just blame the cell.
- last was 3S and hooked up to 15v charger...

Here I present several videos, showing how easily they explode, how secondary fires begin and the aftermath of these fires / explosions

Quick short circuit causing explosion
Cells in fire turn into flame throwers
Single cell explosion
Aftermath of recycled laptop cells explosion

I'll accept your entry but if this turns into a shit fight rather than deal with it I'll just delete or lock.
 

3nergE

Member
Joined
Dec 3, 2016
Messages
101
hbpowerwall said:
I'll accept your entry but if this turns into a shit fight rather than deal with it I'll just delete or lock.

Let it ride dude, we'll just keep adding good information.
Ill link some vids of my 66 cell 'grenade' in a couple of days to show how quietly and non eventfully some cells died.
Its really not an issue.

Besides, its entertaining to see people wig out about stuff and then have others contribute from either side of the fence.

And i get to say stuff like " I=v/r " and know that a bunch of ppl are grinning into their cups of tea while they read.

kind regards.
 
Joined
Oct 8, 2016
Messages
58
3nergE said:
Its not luck, most cells are well designed and hard to kill.
You need short circuits or fire to kill them.

Utter nonsense.
Cells can go into thermal runaway due to high current, high voltage, thermal shock of only 80 degrees,or physical damage. The cells are not well designed. The packs are designed. Packs have protection circuits, which are thrown away along with caution.
 

LithiumSolar

Administrator
Staff member
Joined
Oct 8, 2016
Messages
2,383
DIYTESLAPOWERWALL said:
3nergE said:
Its not luck, most cells are well designed and hard to kill.
You need short circuits or fire to kill them.

Utter nonsense.
Cells can go into thermal runaway due to high current, high voltage, thermal shock of only 80 degrees,or physical damage. The cells are not well designed. The packs are designed. Packs have protection circuits, which are thrown away along with caution.

If you are charging a pack of 80 cells at 20A, there is no way it's going to dump enough current in to one cell to cause it to blow up. It's just not going to happen. And let's stop and think, that's a lot of current and isn't typical. Additionally, some of us are using larger packs of 120, so there's many more cells to absorb the extra current. High voltage is obviously a concern but I don't think any of us are charging at 4.2v anyway. I know I'm doing mine at 4.1v, so there is 0.1v of headroom - and that is very closely monitored. I have personally charged cells to 4.6v before and nothing happened. They just got hot, no venting, no exploding. Physical damage, well, accidents happen as do accidents everywhere in everyday life.
 
Joined
Oct 8, 2016
Messages
58
"there is no way it's going to dump enough current in to one cell to cause it to blow up"

Says who?
This is exactly why the cells kept failing in Mikes DIY video.
Unless you have current monitoring of every cell, don't make those assumptions because current is dictated by ohms law.

"nothing happened"

Another assumption. Watch x-ray footage of a cell getting hot. Just because nothing is outwardly obvious does not mean damage has not been done
 

LithiumSolar

Administrator
Staff member
Joined
Oct 8, 2016
Messages
2,383
DIYTESLAPOWERWALL said:
"there is no way it's going to dump enough current in to one cell to cause it to blow up"

Says who?
This is exactly why the cells kept failing in Mikes DIY video.
Unless you have current monitoring of every cell, don't make those assumptions because current is dictated by ohms law.
Please link to his videos so I can check them out, I haven't seen them yet and am not sure who you're referencing. Says the fuses we're using that break around 5A. Also, you would have a greater chance of winning the lottery than having 19A of 20A charge current going to 1 cell in a 80 cell pack.

DIYTESLAPOWERWALL said:
"nothing happened"
Another assumption. Watch x-ray footage of a cell getting hot. Just because nothing is outwardly obvious does not mean damage has not been done
Duh? My point was it did not vent or otherwise cause damage. It reacted in a safe way like it was supposed to - as do most cells.
 
Joined
Oct 8, 2016
Messages
58
You need to understand.
Thermal damage is progressive. A healthy cell does not explode unless it's an abnormal amount of quick abuse.
All these laptop fires occur because a small amount of damage is done each time. Eventually Lithium builds up on the separator and causes a short circuit.
If you have cells that you have witnessed get hot, they have a much higher probability of going into thermal runaway. Since you don't know the history of each cell, you have no idea how much Lithium has built up and how easily they might short internally
 

LithiumSolar

Administrator
Staff member
Joined
Oct 8, 2016
Messages
2,383
DIYTESLAPOWERWALL said:
All these laptop fires occur because a small amount of damage is done each time.

So then you're saying the protection circuits built in to each battery, that you were saying we all throw out, doesn't actually do what it's supposed to in regards to preventing the fire? Interesting.

Also, you neglected to link to the videos I asked about.
 

CUDAcores89

Member
Joined
Dec 30, 2016
Messages
84
Dear DIY TESLAPOWERWALL:

Yes, all of your points are valid, yes all of your warnings are understood, yes we know this is risky, yes we know of the dangers, yes WE KNOW that many think of our creations as time bombs. But guess what...

We're gonna do it anyway.

Listen, there are plenty of people out there including me building DIY battery packs from these salvaged cells. The truth is that this sort of thing is just going to happen and there is nothing you can do to stop it. Sort of like howpeople that can't afford children have sex and have children anyway, or how people still smoke knowing very well how bad it is for them,it is just going to happen.

This forum gives us a place to collaborate. This forum gives us a chance to share our methods. This forum gives us a place for all powerwall builders to come together and share our safety tips. Without this forum, everyone would be doing something different and people wouldn't have a chance to learn. Some people don't even know li-ion cells need to be balanced of that fusing is a necessity, and this forum gives them a place to learn about these techniques and integrate them into their own packs.

Without this forum, our packs would be even more unsafe.


So yes, we have heard your warnings a million times from others and we simply do not care. It is our business and our risk alone if we blow up our houses, not yours. It is our decision and our decision alone to build these extremely cheap but also dangerous battery packs.If our house explodes or many of the other terrible things happen your videos show, that is our responsibility and our responsibility only.

Oh and by the way, you think your lifepo4 cells are safe? Here is a video that would contradict that:

The truth is every single battery chemistry is dangerous to some degree, but we are willing to accept the danger of lithium-ion. Hell, even lead acid batteries can explode given enough abuse:

NIMH battery fire:

NICD batteries can burn too ifdead shorted:

Every battery chemistry CAN be dangerous! Yes, li-ion batteries are more likely to catch fire than others, but that doesn't mean that other battery types are totally safe either. Your warnings are ultimately falling on deaf ears. We know all of this and WEDON'T CARE! Because we're gonna do it anyway no matter what you say. And of anything bad happens, it is our responsibility only, and nobody else's. If our powerwall's go up in flames, fine you warned us. But it is not your right to be our nanny, and tell us what we can and can't do. We are all adults here, and we take responsibility for our actions, no matter what those actions shall be.
 
Joined
Oct 8, 2016
Messages
58
"So then you're saying the protection circuits built in to each battery, that you were saying we all throw out, doesn't actually do what it's supposed to in regards to preventing the fire? Interesting."

Correct. If you actually read what I said, the protection circuit prevents over charging, over discharging and ensures balancing. It does not have thermal sensors to detect thermal runaway. Your little potshot just backfired.

CUD, I don't believe that. It's obvious that 90% of people building these things have never heard of thermal runaway, let alone how and why it occurs. 95% of people were unaware of short circuit current issues until I brought it up. The fact is, these things simply are not mentioned in the videos. Therefore, noobs are getting only the positive side of the story. Everyone, assuming they have a conscience, has a responsibility to ensure that people are not harmed as a result of following advice in a video.
 

LithiumSolar

Administrator
Staff member
Joined
Oct 8, 2016
Messages
2,383
DIYTESLAPOWERWALL said:
"So then you're saying the protection circuits built in to each battery, that you were saying we all throw out, doesn't actually do what it's supposed to in regards to preventing the fire? Interesting."

Correct. If you actually read what I said, the protection circuit prevents over charging, over discharging and ensures balancing. It does not have thermal sensors to detect thermal runaway. Your little potshot just backfired.

CUD, I don't believe that. It's obvious that 90% of people building these things have never heard of thermal runaway, let alone how and why it occurs. 95% of people were unaware of short circuit current issues until I brought it up. The fact is, these things simply are not mentioned in the videos. Therefore, noobs are getting only the positive side of the story. Everyone, assuming they have a conscience, has a responsibility to ensure that people are not harmed as a result of following advice in a video.

"If you actually read what I said" twice now, this is the third time, please link to the videos by "Mike" that you mentioned above.
 
Joined
Oct 8, 2016
Messages
58
I don't take orders from rude people, in fact the more orders they bark at me the less successful they are in getting what they want. Funny how that works eh
 

3nergE

Member
Joined
Dec 3, 2016
Messages
101
DIYTESLAPOWERWALL said:
Another assumption. Watch x-ray footage of a cell getting hot.

Wow dude, you should read what you write. Who is testing with a LINAC ? Just show me someone who is heating up a battery under one of these to show thermal stress.




DIYTESLAPOWERWALL said:
"there is no way it's going to dump enough current in to one cell to cause it to blow up"

Says who?
This is exactly why the cells kept failing in Mikes DIY video.
Unless you have current monitoring of every cell, don't make those assumptions because current is dictated by ohms law.

"nothing happened"

Another assumption. Watch x-ray footage of a cell getting hot. Just because nothing is outwardly obvious does not mean damage has not been done

Firstly, mike is a bad example, he still thinks the cells are at fault instead of his LVD being wrong and not bottom end balancing.

Saying "Just becausenothing is outwardly obvious does not mean damage has not been done" is a cop out, we can all test cells, so when things go wrong, thats what we do, the math shows you if there is a problem, capacity, self discharge specs. simple


DIYTESLAPOWERWALL said:
You need to understand.
Thermal damage is progressive. A healthy cell does not explode unless it's an abnormal amount of quick abuse.
All these laptop fires occur because a small amount of damage is done each time. Eventually Lithium builds up on the separator and causes a short circuit.
If you have cells that you have witnessed get hot, they have a much higher probability of going into thermal runaway. Since you don't know the history of each cell, you have no idea how much Lithium has built up and how easily they might short internally

The cells blow up due to shorts in wiring nearly universally, which then locally heats inso and causes more shorts. Its nearly always inso fires that lead to runaway thermal situations where multiple cells fail.

What about the sudo 'lithium build up'

... are you trying to make up science ?

<chuckles>


DIYTESLAPOWERWALL said:
CUD, I don't believe that. It's obvious that 90% of people building these things have never heard of thermal runaway, let alone how and why it occurs.

Its not an issue. You can easily see the symptoms as the battery will waste energy.

You seem to think all 18650s catastrophically fail, definitely. This is so not true, just as true as most cars dont kill their occupants screaming with sharp things in their heads, its just an eventual decline, eventually things just 'dont work'

Most cells just continue to pass voltage with no current and have little to no capacity and dont get hot.

Most cells are in laptop batteries and the bms stops charging and discharging as then get below the LVD zone.

Those same cells due to ohms law just dont take a charge, dont get hot and reside in a series module that now has less capacity and gets lower on the low end.

Again, bottom end balance ppl, it shows when your getting cells out of balance in CAPACITY

kind regards
 
Top