Comment by mschuster91
6 months ago
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.
> 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?
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.
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.
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Have you burn-in tested this method?
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.
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.
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...
That is an astounding claim, and requires astounding proof.
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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."
> with the bottom layer being made of acrylic or other plastic that melts.
Why is this bottom layer important?
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.
> 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.
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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.
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If you don't have a bottom layer the sand will immediately fall
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
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like in Minecraft
Presumably so that it melts in case of a fire, so that the sand falls down.
Why is soldering a fire hazard?
Just curious.
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.
Taking a guess, probably has something to do with batteries heating up and solder having a low melting point.