What do you do about devices that need mains voltage AC?
There is an inverter somewhere that converts the battery voltage to whatever you need to power stuff. 110v AC, 220v AV, 240v AC
I can't imagine that's very efficient.
He has powered his house for 8 years using laptop batteries
51–60 of 65 posts
Re: He has powered his house for 8 years using laptop batteries
#52Earlier quoted context omitted.
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 effectiv…
So I need a suppression system to charge my phone now?
Re: He has powered his house for 8 years using laptop batteries
#53The main issue here is that battery technology is not innately fireproof yet. The setup will make more sense for homes when we have switched to fireproof batteries. As for asking people to have fire suppression systems, that's asking for too much.
Re: He has powered his house for 8 years using laptop batteries
#54Earlier quoted context omitted.
> 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.
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.
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.
Re: He has powered his house for 8 years using laptop batteries
#55Earlier quoted context omitted.
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 effectiv…
So I need a suppression system to charge my phone now?
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.
Re: He has powered his house for 8 years using laptop batteries
#56Earlier quoted context omitted.
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. 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.
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.
Re: He has powered his house for 8 years using laptop batteries
#57Earlier quoted context omitted.
So I need a suppression system to charge my phone now?
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.
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.
Re: He has powered his house for 8 years using laptop batteries
#58I've been thinking about similar setups with lots of batteries as I have excess energy I can generate during the day and a lot of otherwise barely usable space in my attic. Fire hazard is my major concern. How do you make sure old (or even new) batteries don't do their usual thing, especially if they are in an environment with unstable temperatures and scarce monitoring?
Old laptop cells are going to need a lot more babysitting than a new LiFePO4 rackmount battery. Those generally do pretty well with the internal monitoring that they bring. Semiconductor fuse as overcurrent protection, passive balancing and monitoring of individual cell voltages seems to get you pretty far. Get your 48V or 51.2V battery in 5 kWh, 10 kWh or 15 kWh cell size from one of the Chinese outlets in dubious q…
yep, I have brick walls downstairs where space is more scarce, the attic has lots of space but also lots of wood lying around.
I guess another possibility is to have the battery pack outside, attached to the brick wall, and ideally away of direct sunlight... but then no wooden roofs. It looks like no DYI is really feasible except maybe a concrete bunker as others have suggested. And even then it's probably uninsurable which is considered a no-no where I live.
Re: He has powered his house for 8 years using laptop batteries
#59Earlier quoted context omitted.
> 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.
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 f…
Fair point. The problem is, the cost for such a consultation will run into the five figures, that's more than even a brand new battery pack setup from a reputable brand costs.
Re: He has powered his house for 8 years using laptop batteries
#60Earlier quoted context omitted.
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 f…
Fair point. The problem is, the cost for such a consultation will run into the five figures, that's more than even a brand new battery pack setup from a reputable brand costs.
I don't see how a short consultation on the matter would exceed 3-4 digits. It's maybe an hour from a specialist to see what is needed. Saving your bacon later on is worth some cost.
Worst case, you might also have existing recommendations or fire code/regulations for battery energy storage systems in your area, and while those specifically may be overkill they give an idea of what is considered necessary. Maybe you could consult your local fire department, depending on how things work in your area.