Fuse links and breakers

[floydR]

Note the lipo cells were stacked pouches as per your cell phone hmm?

The cells were LG pouch cells not Lipo (lithium polymer), A cell phone battery is a single LIpo cell

Whats your take away?

The inability of the concerned parties AES, APS, Fire department to coordinate a response led to delays which led to build up of gases and the explosion.The response was wait 2 hours of pressure building up inside the container and then open the door? The fire suppression system did what it was designed to do (control fire), a one and done system. Not cool the cells as needed.
Later floyd

 

[100kwh-hunter]

Source: https://electronics.stackexchange.com/questions/565299/dc-parallel-breakers
There are multiple examples of this design

The design in 2p makes also sure that the switch will do its job, you make it immediate bi directional.
Most of those breakers are one direction.

Joking right? Hope so. CO2, halon or dry chemical extinguishers only for electrical fires.

Halon is forbidden in my country, but indeed a very good one. several years ago i stumbled upon a extinguisher called: bl500 or something.

your info from youtube

The last serval years i noticed a LOT of misinformation on YT, most are for the internet points....

d) spacial temperature monitoring (or in between PTCs per cell? lot of wires/data to handle - there isnt a multi channel temp alarm system at sensible price). Maybe provide a hood above a suitable cluster of cells with an alarm switch (room thermostat?) Chain the switches together as needed for an area alarm.

How far are you willing to go? how much money you want to spend?
Ilike to take it as far as possible on the cheapest way i can make it and yes with KISS (dont mean the band) written all over.
Some simple heat fuses, get the rate(A) you must have (dc or ac(again not the band) does not matter so much).
Buy them at the temp you want them to burn out (in my case 250v 20A and burn at just 65C).
One heater and your whole pack is down, critical point of self-combustion with lithium is around 145C.
Or daisy chain a lot of those fuses and connect them to a breaker that has a trigger.
You want to solder them with the fuse under water btw, your soldering iron is too hot for those buggers.
Regarding your alarm is also a simple one.
If you connect a relais in closed operation in your circuit and the power is cut off from that bank, it will activate a other circuit of your choice.

 

[Boron]

spacial temperature monitoring
How far are you willing to go? how much money you want to spend?

I came across this neat little battery temp logger, lasts a year, keeps months of points for ca £15
Put a hood above your battery bank to collect heat and dl the log to pc app occasionally to get your heat trend picture IMHO a cheap alarm system

​

elitechlog.com/rc-5usb-temperature-data-logger/
no affiliation, -

there are other cheapos from EB PRC at half price

 

[Korishan]

sorry about the bold shout, its what this board does?

Shift-Ctrl-V removes formatting in the clipboard
Not necessarily the forum. The site where you copied the text from had formatting tied to it, even if you don't see it. I've seen it even when copying from the Address bar for some reason

 

[italianuser]

@floydR That report 75pp should be a sticky, compulsory study for all wannabee pack builders.

Yes, there's quite a few threads about safety and the McMicken failure was brought into the discussion I remember.

A thread about safety built using a Risk Management approach could be good for all DIYers. Exactly how we do in IT management by identifying risks, threats, probability, mitigation plans, impacts. The result is a set of matrixes capable of addressing (potentially, depends on the effort you put into the job) every single risk.

 

[Boron]

Dunnit K thnx

 

[Boron]

You over estimate the attention span of the Solar Numpty

https://www.youtube.com/@HBPowerwall/videos

This guy spent 7 years and 400 vids meddling with clapped out Lion cells and often made the proud boast that he didn't do sums.
Strictly "suck it and see". No recognition of the inherent dangers to health and property and he had 800k followers.

 

[OffGridInTheCity]

You over estimate the attention span of the Solar Numpty

https://www.youtube.com/@HBPowerwall/videos

This guy spent 7 years and 400 vids meddling with clapped out Lion cells and often made the proud boast that he didn't do sums.
Strictly "suck it and see". No recognition of the inherent dangers to health and property and he had 800k followers.

Disagree. 'This guy' and others like him was the inspiration for my own successful, perfectly safe, powerwall.

 

[Boron]

7 years ago we were a lot more naive about Lion cells than today

https://www.youtube.com/results?search_query=lithium+ion+battery+fire

I agree that his site back then was an inspiration but would that same initiative gain traction today?

View: https://www.youtube.com/watch?v=BnJZBbDDVH8


My grouse is that if vids were made showing a rank amateur playing with chemicals on his kitchen table hoping to make his own fireworks, would you have the same sympathy. I trawled through most of his vids and a lot of fooling around that he did was clearly very risky

YT wouldn't cos its one of their proscribed forbidden categories - https://support.google.com/youtube/answer/2801964?hl=en
Its not only with 18650 batteries but handling ELV 24v/48v dc stored energy with very high fault current potential.

This is the point of my OP.

 

[OffGridInTheCity]

You've certainly made you're opinions clear - and it's not new. One of the key points of this forum is to provide guidance to cells and techniques and best practices and this has been successful. Many of us have had good experiences building and operating perfectly safe, well behaved, successful powerwalls and batteries built on 2nd hand (and new) 18650 cells - and continue to build, expand, and operate them.

 

[italianuser]

This guy spent 7 years and 400 vids meddling with clapped out Lion cells and often made the proud boast that he didn't do sums.
Strictly "suck it and see". No recognition of the inherent dangers to health and property and he had 800k followers.

Well, I respect the person who created this forum. It's easy to criticize someone but, in actual fact, HB produced so much valuable content (forum included) to spread information about making, testing, and also keeping things safe.

My grouse is that if vids were made showing a rank amateur playing with chemicals on his kitchen table hoping to make his own fireworks, would you have the same sympathy

I'm a very critical person, in general. From my point of view HB has always done the job in a professional way, you can verify that by looking at the results he achieved, even only simply looking at the powerwalls: there's quality, which means there has been a lot of research done before. And the research is what you see in his videos.

Now, if I wanted to be rude, which I usually aren't, I'd ask you "but what are you giving to the community?".

It's easy to negatively criticize someone. What HB has done is difficult, time consuming and risky. That's why I appreciate him.

 

[Boron]

Glad to see you agree with me - Safe practice is all important with Solar systems, mistakes can have very serious consequences as I have demonstrated. The ABYC has a very relevant forum https://www.cruisersforum.com/forums/f14/abyc-and-batteries-129873.html and a long history of stored energy (formerly LABs) afloat together with a set of internationally recognised standards which Im sure you are aware of. Its very informative on matters of electrical distribution and useful circuit devices specially designed for ELV dc high current use. For example its not easy in the EU to source Class T fuses which are standard (or should be) in the US. We have to resort to Siemens style NH knife fuses, or HRC cartridges rated for dc (scarce). The Fuse Carriers for this type are extremely expensive and notoriously difficult to source ($$$$ as much as your panels). There is a work around but I dont know where this should be posted. We dont have anything like the DIY Solar culture here as exists in the N America and Australia.

 

[Boron]

From my point of view HB has always done the job in a professional way,

Look you misunderstand me. I am NOT knocking the guy. But look at his early vids where he plainly and clearly states that he is an unskilled amateur who doesnt do sums (his words) and just took on a desire to recycle old laptop batteries that he could source for free by the ton. Fair play. Yes he muddled through with all manner of failures and bad outcomes and all credit is due to him for frankly exposing to all followers how he screwed up. Ignorance was bliss back then . As he says frequently " I am not giving out advice only telling you what I did". So this must not be mistaken for a professional approach as that implies your work can demand a consultant's fee .

His prime value was his unedited catalog of how badly you can get it wrong - he deserves a gold medal for those 1000's of hours service muddling through (400+ vids x 7 years). A real pioneer.
But this is 2024 and the tech is evolving so rapidly AWS. Ive already got an 8s bank of SiBs on test and a big fight going on with a Supplier of fake cable sold as 6mm2 when its core is only 4mm2 (and another one which is 3.1mm2). The snake oil carpetbaggers are out in force.

 

[Korishan]

Look you misunderstand me. I am NOT knocking the guy. But look at his early vids where he plainly and clearly states that he is an unskilled amateur who doesnt do sums

How about you look at his later videos where he demonstrates what he's learned over the years and the quality of his material work.
The videos aren't a "How To", but instead they are a "Progression of Learning and Vlog" of his path.
Yes, when he started out he was clumsy, didn't do proper maths, used random cells, carelessly handled cells, etc etc etc.
However, over the years he's refined his thoughts, practices, actions, and skills. Now he's very polished in his work, knows the practical limits of cells of various different kinds of chemistries, and even has helped build commercial level systems that have been approved by EEs in his area.

Seven years ago the EEs would have laughed at him and turned and left, and probably sent the city after him. Now, he's respected and is also asked for information.

So don't go judging a person by what they did 7 years ago, even of 4 years or even any number of years ago based on their current standing. You should look at where they are now and the hurdles they've overcome to become a better person and gain many new skills in the process, and have helped many, in the thousands, to come to a better understanding of the topic. Because he used to be untrained in the area, he has a lot of positive perspective of those who are currently there as well and can relate to them, and help them gain the knowledge they need.

Granted, he doesn't always step in on this forum, however he does post videos and more so, he does a lot of on-site help in Aussie.

If your viewpoint is to give credit where due, please do so in a single posting. When you don't finish your thought in the single post, it can appear that you are bashing or knocking someone. Use comparisons of what was to what is now to help show progression of improvement and not just focus on what was. This makes it appear that there is nitpicking of the past and stating that things aren't any better.


We've all started with ignorance. It takes time and patience to learn the skills we want to posses and a lot of times takes humility when we're wrong about something and to correct it.

 

[italianuser]

Look you misunderstand me

I'm not misunderstanding anyone. I find the tone of your post disrespectul, that's the point: the tone, the phrasing and the words are. Starting from the phrase "This guy spent 7 years and 400 vids meddling with clapped out Lion cells". Because "this guy" pays with his money to keep up a service that you are using.

So this must not be mistaken for a professional approach as that implies your work can demand a consultant's fee

What you're saying makes no sense. I'm a professional in my job. And nobody would ever judge my professionality, nor yours, by checking out what I did in 1987.

Sorry, your post makes no sense for me.

 

[paulie]

Pete was my inspiration. I came to the party late about 2 years ago. My 18650 journey has been great. Have since learnt all of the pitfalls and I am quite happy with these cells. I am using the MPP solar and JK bms along with a thermal camera. I am getting pickier with these cells as I progress but my earlier frankenstein packs are performing well and cool. As far as I am concerned Pete is a God and Boron is borderline rude

 

[completelycharged]

You mentioned armchair opinionators and wondering about your suggestions :
a) perhaps use wing nuts for quick action on the battery studs
b) make busbars slotted rather than just drilled holes (like Maxi fuses strips)
c) needs in situ handles of some sort to grab the cell for quick extraction (could even be too hot to hold)

a) wing nuts are for wing nuts - if you need speed to disconnect manually your way too late and generally unable to manually disconnect anything in the pub....
b) slotted bars reduce the csa and current carrying capacity and thermal dissipation - although they do allow for lax positioning tollerances.
c) cells should typically be in pre-compression so trying to pull one out with a handle is non sensical and way too late

The cross balancing connections in that pack layout look quite dangerous/hazardous if the busbar connections for each pack are fused/breaker separately as they should be. If your going to cross balance with very thin wires fuse them or make sure when they melt / catch fire they are not going to do any damage. The cross wiring is fine, until you either have a cell imbalance issue or during a fault one or more of the series packs is left in circuit.

In terms of your comments in relation to fuses and breakers, like "In parallel, one contact could weld closed" you need to understand the mechanics and thermal properties of breakers better. Parallel breakers are fine if they are individually capable of handing the peak fault current.

AC and DC breaker use can be very particular to the expected fault current, which the majority of packs on this site have higher resistance in the circuit, which means the true fault peak amps tends to be quite low and therefore virtually any breakers would work fine. AC has the benefit of self extinguishing zero crossing voltage, while DC plasma arcs tend to get a bit wild with higher energy.

Once you get into the rather heavy duty setup and very low IR cells and associated wiring, breaking fault currents over 10-20kA starts to become a problem for a lot of equipment (due to the energy dissipation in the few mS that contact inertia plays and the resulting I2R thermal build - i.e. usually vapourisation). How many people actually know thier real busbar curcuit pack resistance (cell IR + wiring to and including busbar) and theirfore the actual likely peak fault A - also taking into account the cell dynamics during fault currents ?

Knife switches are genrally hazardous and needlessly increase the exposed conductive surfaces. Have an accident or two over time with plasma explosions you tend to change your view on exposed copper anything. They look good in sci-fi movies and that's about it.

 

[hbpowerwall]

I wouldn't do it again given how far the whole idea has come in the past years, LifePo4 are cheap and accessible, back then 18560 cells were cheap and accessible and scaled from a hut in the desert of Africa to a aussie bloke in his shed with a fun suck and see outlook on life.. Without my fucking around many would have also had to suck it and see. I didn't teach, I shared my journey - That battery that went up wasn't mine, it was POORLY managed *not at all, RAPED every single night with zero concern for DOD and a perfect example of what not to do..

 

[100kwh-hunter]

I wouldn't do it again given how far the whole idea has come in the past years, LifePo4 are cheap and accessible, back then 18560 cells were cheap and accessible and scaled from a hut in the desert of Africa to a aussie bloke in his shed with a fun suck and see outlook on life.. Without my fucking around many would have also had to suck it and see. I didn't teach, I shared my journey - That battery that went up wasn't mine, it was POORLY managed *not at all, RAPED every single night with zero concern for DOD and a perfect example of what not to do..

DONT forget you were one of the first ones that was climbing that high stairway!
With practical no knowledge at all, almost nobody had knowledge on the public boards.
Sometimes there is one way to find out if your gut feeling is on the right end, go for it.
Dont follow your dreams, chase them.

When HB had the grasp of safety he even put a 40ft container on his property, before that he put the cells into his shed, even bought some metal sheds for his powerwall build.
There is a lot of safety in his vids.
On his journey he tested also a lot of "testing" aspects to keep healthy cells.
The same goes for ?jehu? if i see some of his first vids.......

The same goes for me and playing around with different typs of chemistry of cells, NiMh is a succes.
Zinc bromine not ect.

Without this forum i would not even dare to play with 18650, nor even would build myself a powerwall.
Let alone save!
Thanks to the "meddling" and "fooling" around of hb and forum members i save big time every year on my bills in a very safe way.

Yes lifepo4 is getting really cheap, below 80 euro a kwh, without bms!
But i get my cells for free, so why not mix

With kind regards Igor and special thanks to Pete -->HBPowerwall and this community for sharing knowledge.

 

[100kwh-hunter]

That particular vid posted by Boron, if i remember correctly had something to do with the positive busbar making contact with the negative side of the cell.
When there was a massive power draw, one of the cells or bus heated up and melted his way into the holders by force of the tie wraps.

The cells were properly tested and the wire fuse was rated for 7A(to high in my opinion).
This pack(not hb own build btw) was discussed in this forum somewhere.

PS : Before we pick camps, maybe some people want to go to deep with their learning.
And want to have answers on non-existing issues! Better safe than sorry, remember the only stupid question is the question that is never asked!
We are all human with different backgrounds, age, money, different locations and different languages...

Correct me if i am wrong here:
If i say to a English woman: lets dance, we will do a shuffle or even a tango.
If i say lets dance to a American, i was picking a fight.
A tango is not only a dance, but we all "tango" also with our partner.
Ect

With best regards Igor from the Netherlands