diy solar

diy solar

Containing a battery pack meltdown.

What is self-evident is that this is a total unsafe joke. Hopefully theoretical.

The point of me being an ass here is so that some kid doesn't burn his house down cuz "some guy on DIY Solar Power Forum" thought it was a do-able idea after googling a bit. I know - I'll hang a water-baloon over mine!

Get serious. Get safe. Battery power isn't a joke, and shouldn't be treated like one.
 
What is self-evident is that this is a total unsafe joke. Hopefully theoretical.

The point of me being an ass here is so that some kid doesn't burn his house down cuz "some guy on DIY Solar Power Forum" thought it was a do-able idea after googling a bit. I know - I'll hang a water-baloon over mine!

Get serious. Get safe. Battery power isn't a joke, and shouldn't be treated like one.
I actually like his( @justinjja ) thought process and it is getting us all to think about what we are dealing with and how to minimize the potential of a fire. Actually water isn't very conductive my itself and most batteries are under 60 volts which is safe to touch. Water with salts in it get more conductive but not a tone.

Someone needs to settle down. This is a great thread.
 
15Kwh will heat up and completely boil out around 21 liters of water.
99% of the time it is one cell/connection that starts the reaction of destruction when a cell goes bad after everything is setup.....during setup anything can happen but again the whole pack might be on the edge of explosion but a couple cells go first and the water should stop the run away reaction.

I have Smartthings automation at the house and have a temp sensor that tells me the cabinet temp and alerts me of when it gets high or low.

And I just added a smoke detector above everything also.
 
If the battery is properly fused and temperature monitored I don't see why such extraordinary measures would be useful. Certainly vehicle manufacturers aren't doing anything similar.

While the chemistry isn't not nearly as safe as lifepo4, proper cooling, fusing, voltage, current and temperature monitoring, venting, and containment are sufficient.
 
I actually like his( @justinjja ) thought process and it is getting us all to think about what we are dealing with and how to minimize the potential of a fire. Actually water isn't very conductive my itself and most batteries are under 60 volts which is safe to touch. Water with salts in it get more conductive but not a tone.

Someone needs to settle down. This is a great thread.
Pure distilled water isn't conductive.

Literally any other water is conductive enough to be a problem. It doesn't need to be salts specifically. Basically any impurities do the trick. Like tap water that's been sitting in a container for months growing who knows what bacteria.

Source: I have to measure conductivity weekly in my chiller system at work. Conductivity is a function of total dissolved solids for practical application. Salt counts as a dissolved solid, but it's not the only thing that will increase said conductivity.


Never mind the previously pointed out aspect of needing to boil the water out of the container before the container will melt and rupture in the first place.
 
If the battery is properly fused and temperature monitored I don't see why such extraordinary measures would be useful. Certainly vehicle manufacturers aren't doing anything similar.

While the chemistry isn't not nearly as safe as lifepo4, proper cooling, fusing, voltage, current and temperature monitoring, venting, and containment are sufficient.

Well the news articles that pop up from time to time about Teslas going up in flames,
despite cell level fuses a good BMS and active cooling.

Make me think that my extraordinary measures could be useful.
At the very least for peace of mind.
 
Google says 0.6g of lithium per 18650.
so there is something like 720g of lithium.
Burning lithium is 43.1MJ/KG so thats an extra 31 Mega Joules of heat.

I mentioned there would be a hole in the lid with a fan, so no pressure.
Imagine how much hydrogen is in 8oz of water
 
Pure distilled water isn't conductive.

Literally any other water is conductive enough to be a problem. It doesn't need to be salts specifically. Basically any impurities do the trick. Like tap water that's been sitting in a container for months growing who knows what bacteria.

Source: I have to measure conductivity weekly in my chiller system at work. Conductivity is a function of total dissolved solids for practical application. Salt counts as a dissolved solid, but it's not the only thing that will increase said conductivity.


Never mind the previously pointed out aspect of needing to boil the water out of the container before the container will melt and rupture in the first place.

It's a problem in the sense that the pack will be ruined if I have a fire that is extinguished by this system.
Which isn't a problem. Now if I have a leak that ruins the pack, that is a problem.

But as far as making the problem worse, not at all.
My 48V potential points can stay 1 inch apart.
Even even in very dirty water, 1 inch is going to mean less than 1 amp at 48v.
 
I've heard of some people on here talking about putting sandbags above groups of cells on like a mesh grate. I don't think lithium and water mixed too well.
That would be true of elemental lithium but there isn't any of that in lithium ion batteries, they use a lithium oxide.
 
Pure distilled water isn't conductive.

Literally any other water is conductive enough to be a problem. It doesn't need to be salts specifically. Basically any impurities do the trick. Like tap water that's been sitting in a container for months growing who knows what bacteria.

Source: I have to measure conductivity weekly in my chiller system at work. Conductivity is a function of total dissolved solids for practical application. Salt counts as a dissolved solid, but it's not the only thing that will increase said conductivity.


Never mind the previously pointed out aspect of needing to boil the water out of the container before the container will melt and rupture in the first place.
Might want to read this....

Also, you wont have to boil the water out of a water bottle before it explodes from the pressure. Keep it sealed and it will open on it own faster and spread water over everything.

Also most car manufactories have there packs in coolant that is likely 90% water.
 
Might want to read this....

Also, you wont have to boil the water out of a water bottle before it explodes from the pressure. Keep it sealed and it will open on it own faster and spread water over everything.

Right my assumption is that it would open.
But I have seen videos with people boiling water over a camp fire inside a plastic water bottle.
 
My test was simple, stick a coupler alligator clips in my nasty Texas tap water,
Crank volts up to 48, observe current at 1in
result: 20 Milliamps
 
Thanks, at some point I mixed up gallons and litters...
I'd say I'm an idiot, but I'm pretty NASA crashed a spaceship due to a similar problem :D

And I helped give them the flight computer to do that.

https://trs.jpl.nasa.gov/bitstream/handle/2014/33518/94-1363.pdf

Previously, I read that NASA was going to require all providers to work in the metric system. But they discovered they could save something like $10 million or $100 million by letting vendors use whichever system they preferred, so not excluding those with equipment having English units.


A couple months after that little units mix-up, NASA then relied on input from a single sensor to make critical flight decisions.

My test was simple, stick a coupler alligator clips in my nasty Texas tap water,
Crank volts up to 48, observe current at 1in
result: 20 Milliamps

No problem then!
It's not enough to stop your heart, just enough to make sure you can't let go!
:ROFLMAO: ??‍♂️⚡⚡
 
Might want to read this....

Also, you wont have to boil the water out of a water bottle before it explodes from the pressure. Keep it sealed and it will open on it own faster and spread water over everything.

Also most car manufactories have there packs in coolant that is likely 90% water.
Yeah. It says salts make it more conductive. So much so that sea water is more conductive than humans are.

Your statement was originally that water isn't very conductive at all 'unless salts are added' (to paraphrase a bit). You stated that salts wont be present, so conductivity isn't a concern.

I refuted the claim that water isn't particularly conductive without salts by simply stating that salt is not the only dissolved solid that can, and does, increase conductivity.


Again, source: My calibrated conductivity meter at work that I use every single week.

Our system uses no salts. In fact, its tested for such things specifically to avoid the corrosion problems associated with them. And yet, the conductivity is typically rather high from other non-salt dissolved solids.


Regarding getting it to open sooner, yes. You could use a thin film over the port leading to the battery. However, you still have to have a sufficient amount of water to put it out. You would need the water container to be built into the lid of the system to transfer as much heat as possible and honestly, by the time the fire is large enough to boil a few gallons of water - the system is already ruined and chances are the fire has spread.

But if everything is perfectly designed, and everything is sufficiently isolated from other flammable stuff (typically via distance) and you can heat your water up reasonably fast via a fire in your battery box and the stars align nicely. Sure. The water might help.


However, all of those things combined would mean the battery could just burn itself to the ground before anything else catches fire.
 
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