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Fire Safe Cabinet
#11
I just measured the steel with my slide gauge. 2mm! Thats quite fat i guess.
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#12
(07-18-2020, 03:31 AM)camthecam Wrote: Just vent into neighbours house.

Yes, choose carefully where you aim the vent. Li-ion fires generate huge amounts of flammable gases, so it may amount to a monster flamethrower that would make Elon's Musk's look like a toy.  For some numbers, here it is claimed that they produce 330L/kWh of flammable gas (p. 57), and it is recommended to have a forced ventilation rate of 0.32 cfm/kWh (p.48).

For example, a 2019 Li-ion fire in a battery substation in Surprise, AZ generated a flame 75 feet long by 25 feet high that threw a firefighter 75 feet.
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#13
(07-18-2020, 10:47 PM)gauss163 Wrote:
(07-18-2020, 03:31 AM)camthecam Wrote: Just vent into neighbours house.

Yes, choose carefully where you aim the vent. Li-ion fires generate huge amounts of flammable gases, so it may amount to a monster flamethrower that would make Elon's Musk's look like a toy.  For some numbers, here it is claimed that they produce 330L/kWh of flammable gas (p. 57), and it is recommended to have a forced ventilation rate of 0.32 cfm/kWh (p.48).
  Read the pdf. The container sized fire storage looks like a hell on earth occurrence Big Grin .   Maybe they should adopt the fireworks
 
   storage with high earthen walls to prevent fire radiating to adjacent containers.

jimjr
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#14
(07-19-2020, 02:17 PM)Jim Jr. Wrote: Read the pdf. The container sized fire storage looks like a hell on earth occurrence Big Grin .   Maybe they should adopt the fireworks storage with high earthen walls to prevent fire radiating to adjacent containers.

Large pack (powerwall) fires needn't be so bad if the pack is properly designed, e.g. see here for a test on a g2 Tesla powerpack. But that's using state-of-the-art tech to improve safety (most of which - alas - is currently impossible to emulate in DIY powerwalls, e.g. tweaks to cell chemistry, separators, highly customized BMS, etc).
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#15
(07-19-2020, 04:23 PM)gauss163 Wrote:
(07-19-2020, 02:17 PM)Jim Jr. Wrote: Read the pdf. The container sized fire storage looks like a hell on earth occurrence Big Grin .   Maybe they should adopt the fireworks storage with high earthen walls to prevent fire radiating to adjacent containers.

Large pack (powerwall) fires needn't be so bad if the pack is properly designed, e.g. see here for a test on a g2 Tesla powerpack. But that's using state-of-the-art tech to improve safety (most of which - alas - is currently impossible to emulate in DIY powerwalls, e.g. tweaks to cell chemistry, separators, highly customized BMS, etc).
 I was referring to my partner in the magic smoke department , John Murphy ------- Murphy's Law   Big Grin Big Grin Big Grin Big Grin Big Grin


Jim jr
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#16
Promatec or vermiculite sheets.
From both sheets you can easy make a chimney to the outside.
Both materials are very fire proof and very good insulating.
As mentioned before: a proper designed power wall is very safe--->fuses on each level.
If i remember correctly, Korisan made a topic about this, from cell level fusing up to your solar panels or generator.
For cell level i strongly recommend glass fusses!
Best, Igor
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#17
I just finished my fire safe cabinet a few days ago.

It's an old metal box too. I sanded and painted it new


then some works for thermal care. 
 

I dont want the box to be 100% airtight, but I want to keep the fire into the box if there will be one, so I don't want to use an open ventilation system. 


Using some computer cpu cooler (Intel boxed cooler) at the inside...


...and some 100 x 100 x 18mm passive radiators...
 

...with thermal paste...


...at the outside


will be tight fitting for the 14s60p system


fermacell at the boddom and 40mm mineral wool WLG032 (fireproof 1.000°C +) at the walls
 

getting even tighter but fits
 

7 packs in parallel...


...intermediate floor with fermacell...
 

...and 7 more packs
 

all packs are separated with fermacell separators with 12cm in high = 2cm more then the packs to ensure ventilation.
In front some space left for cables and connectors


BMS / active balancer, 100A DC circuit breaker, voltmeter and fan controller (not on this picture, now it's mounted at the left of the bms)
 

another 40mm of mineral wool on top


 

 

 

 

now I am running some tests to evaluate the thermal developement.


But as far as I can say at this time, the temps inside the box are OK and stay below 30°C at a maximum discharge current of 30 ams = 0,5A per cell


the load test is not done yet and I will try to load twice of the current = 60A / 1A per cell so that the powerwall can easily fully charged in one day
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#18
Hey, it seems like you made a lot of thoughts about this before you built it.
The only thing i wouldnt like is not t o be able to see the cells quickly, especially the lower story/floor of your box.

Which BMS is that?
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#19
(08-29-2020, 07:00 AM)2weiund2wanzig Wrote: The only thing i wouldnt like is not t o be able to see the cells quickly, especially the lower story/floor of your box.

Yes I already noticed this disadvantage too.
But the main goal of this powerwall for me is to learn and figure out some weak points of construction and in the building process.
It's my first test-build before I go to the bigger 14s240p system which will be into a bigger fire proof metal cabinet where I canmaintance each pack more easily then with this box.


(08-29-2020, 07:00 AM)2weiund2wanzig Wrote: Which BMS is that?

You will find it on Aliexpress with keywords "active balancer bms 24s" for example here -> IC GOGOGO Store
On eBay too but mostly much more expensive.

There are a few different versions with 0,6A balancing current, 1A and 2A, and each version with different charge/discharge currents. All versions are usable for 13s to 24s systems.
I am using the 2A / 150A version, costs about 140USD
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#20
I now finished a second build. And because the at 1A max per cell there is no noticable temperature raising I didn't use some extra coolers this time, but voltage / Capacity status / temperature display
[Image: juqntl1.jpg]

see the building process here ->  18650 Garden-Powerwall with 3KWh, no 4,6KWh no 10 or better 25, wait 50KWh in Germany
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