[mschuster91]

Jesus. No cell balancing, protection or monitoring that I can see, and most importantly - wires directly soldered onto the battery instead of spot-welded. That's a fire hazard waiting to happen.

People, if y'all ever build your own battery pack, please think about safety. Or if you don't, place a giant bucket of dry sand above the pack, with the bottom layer being made of acrylic or other plastic that melts. That's about the only thing that can stop a battery fire.

[pantulis]

> place a giant bucket of dry sand above the pack, with the bottom layer being made of acrylic or other plastic that melts.

Honest question: is this a real hack that people do in these situations or did you just come up with it?

[mschuster91]

It's a hack I started doing after a friend's home almost burned down from a vape battery gone bad.

In any case, dry sand is one of the methods firefighters use to put out battery fires, the other being dumping it in a giant vat of water (that's what's done for electric cars) or class D fire extinguishers which are extremely fine powdered salt.

[arghwhat]

Acrylic is itself flammable, massive amounts of sand would be required to fully submerge and cool all cells (and therefore hefty acrylic sheets less likely to give), and it's likely that the sand will not spill correctly and evenly.

Please only use properly designed and tested fire suppression systems, as hack jobs might not help at all and do harm from the false sense of security leading to lack of actually effective mitigations.

[dzhiurgis]

So I need a suppression system to charge my phone now?

[mschuster91]

At least mass-market phones and their batteries by reputable manufacturers go through rigorous testing. The sole exceptions I'm aware of are Samsung's infamous last-ever Note phablets and a few batches of iPhones. Fires of mechanically intact phones are rare.

Shoddy knockoffs and cheap Chinesium garbage however, that's a different thing.

[arghwhat]

When you only have one battery cell it's also hard to screw up battery management, and phone batteries are rarely driven past their prime (no one wants a phone with 50% remaining capacity). The odds are not zero though, as the battery can develop internal shorts from imperfections like dendrite growth over time.

The odds get much worse when you have tens or hundreds of kWh comprised of hundreds or thousands of cells, especially in OPs jank setup with improper battery management and cells that are all already at the end of their life and likely have significant internal damage already.

[hengheng]

Have you burn-in tested this method?

[metalman]

He did and end run around saftey, and just put the whole system in a shed, which in any real emergency situation , dramaticaly reduces risk to life and property. Also each battery bank is.air gapped , which will significantly reduce any fire from spreading to adjacent banks. The system looks well made, and has 8 years up time. I live off grid and am useing lead acid batteries, but would like to switch to sodium.

[arghwhat]

The banks are "air gapped" by just a few cm, are all interconnected with excellent heat conductors (the bus bars), is insulated with flammable plastic, and sit on a flammable shelf in a flammable shed.

There is no fire safety there. Let's just hope the shed is very far from a house, fences, trees, bushes, or anything else that could catch fire and close any "air gaps" and cause harm.

[metalman]

Edit, digging in, each single cell is fused, very nice work, and exceptionaly safe to run. As good as anything built, anywhere.

https://secondlifestorage.com/index.php?threads/glubuxs-powe...

[IAmBroom]

That is an astounding claim, and requires astounding proof.

[metalman]

I'm game, but first, would you be so kind as to give some indication of your practical or theoretical understanding of the subject of off grid, grid tie or remote/small grid or even portable power systems. I will restate that the homebuilt system under discussion is remarkable in just how simple and effectivly it has been designed to reduce risk to the lowest possible levels, ie: idivdual cell fuseing, coupled with very low power/volume density in a physicaly removed electrical building, means that the conditions for a fire are very low, the chance if that fire spreading to the whole bank are very low, and any possible, small, slowly burning fire then escaping the electrical build is low, and the chance of that small fire then injuring any unsuspecting indivuals is the exceptionaly low. The only astounding part is that the guy who designed and built it isn't bieng consulted in formalising his method for wider adoption.

[esseph]

From the article:

"Behind the success of this project lies an unwavering determination to overcome technical challenges. Glubux had to solve several problems over the years: cell balancing, electrical safety, and storage management. But his system keeps improving. For example, his energy production capacity has increased from 7 kWh to 56 kWh."

[nextaccountic]

> with the bottom layer being made of acrylic or other plastic that melts.

Why is this bottom layer important?

[arghwhat]

If the batteries catch fire the acrylic bottom will melt and automatically dump the sand onto the fire.

This is a questionable setup though. You'd need massive amounts of sand dumped evenly, which requires more design and verification. Acrylic is also itself flammable.

A basic water based fire suppressor would not extinguish a battery fire but it will cool it and the room, limiting spread.

Let the experts design this kind of thing.

[mschuster91]

> A basic water based fire suppressor would not extinguish a battery fire but it will cool it and the room, limiting spread.

That's the thing: it will not, quite the contrary - unless it's many tons of water at once that quench the fire, the burning lithium will just go and create hydrogen gas that in turn recombines and leads to an even larger fire.

[arghwhat]

I think you're confusing suppresing the fire and extinguishing it. You are not trying to stop battery cells that are currently on fire from burning - you will just have to wait for those to be out of fuel. The purpose of fire suppression is to stop new things from heating up by the fire past the point of combustion, catching fire and thereby spreading it - be it more battery cells, construction materials, you name it.

Modern EV fire suppression systems for parking garages use high pressure water mists to contain the fire to a single vechicle for example. This keeps neighboring cars cool and avoids them catching fire, and cooling down the burning vehicle may avoid spread to more battery banks or other flammable materials.

[mschuster91]

> Modern EV fire suppression systems for parking garages use high pressure water mists to contain the fire to a single vechicle for example.

Indeed but look at the size of the pipes and the pressure they're operating at. Far above the typical residential, what, three bars that come from the utility. The volume of water is the key.

[arghwhat]

Your home residential battery is not an entire parking garage full of EVs, so looking at their pipes and pressures is not relevant.

Those pipes are dimensioned to be able to suppress fire in every parking booth of an entire parking garage full of EVs, each of which packing more of a punch than most residential battery installations. While it cannot handle every car being on fire, it needs to handle any car being on fire when it goes off.

This is orders of magnitude more powerful than what you need for a small residential setup. Have a professional evaluate what system is best - if they suggest a sprinkler system, which they might, I am sure they would understand the capacity of your residential water supply and suggest upgrades (new piping to mains or buffer tanks) as needed.

[Etheryte]

Do not use water to try and put out a battery fire. It's not as bad as throwing water on burning oil, but it's not far from it.

[arghwhat]

Battery fire suppression systems often use water, and firefighters will also certainly apply water. Just don't walk up to the cell with a bucket of water.

Water can and is used to cool batteries during battery fires, and more importantly, to cool the surroundings so that the fire cannot spread to, say, neighboring banks/cells or construction materials. Modern EV fire suppression systems for parking garages use high-pressure water mists to avoid the fire spreading to neighboring vehicles for example.

The recommendation about oil and water focuses on a larger container of liquid fuel that is on fire at the surface and heated far past the boiling point of water, such that dumping a large volume of water onto it all at once causes it to immediately boil and explode, spreading large amounts of oil as a mist in the air, which both spreads the fire and causes a much more violent combustion. A water-based fire suppression system (not a guy with a bucket of water), or a firefighter with a water hose, can absolutely extinguish such a fire.

Hacking together a sand container of acrylic may well do nothing to limit the fire while simultanously giving it more fuel (acrylic) and pathways to spread to (whatever the acrylic is near).

The point is: Don't hack together a fire suppression system, leave that to an expert please.

[iokanuon]

If you don't have a bottom layer the sand will immediately fall

[iokanuon]

Actually thinking about it - why not have everything encased in sand all the time, you'd just have to be a kid playing in a sandbox when doing maintenance

[mschuster91]

Heat management. A battery that's surrounded by air can cool itself by convection. A battery that's buried in sand will eventually reach thermal saturation with the sand... at a temperature that it really really should not be at.

[lukan]

Because sand everywhere is kind of annoying?

And dangerous for any moving parts?

[IAmBroom]

Very few moving parts in most batteries.

[lukan]

But batteries are often close to machines in need of energy. And even walking with sandy hands to the sink to wash then, will spread sand. Also some batteries have active cooling.

But a home installation might be done in a way that it is managable though.

[f4c39012]

like in Minecraft

[Scarblac]

Presumably so that it melts in case of a fire, so that the sand falls down.

[Arnt]

Why is soldering a fire hazard?

Just curious.

[SuchAnonMuchWow]

Soldering dump a ton of heat into the cell, which has chances of destroying the cell. That's why most of the cells are spot-welded: its similar to soldering, but its much quicker and is localized only on the part of the metal that need to be melted, so the heat don't have time to reach the cell itself.

[thehta]

Taking a guess, probably has something to do with batteries heating up and solder having a low melting point.