MPPT and bus bars in steel cabinet?

[pda1]

I was just looking at the Forum "Up in Smoke" and alot of those posts were very informative.

It's resolved I'll put the controls and bus bars into a steel cabinet with some venting as needed and a fan, maybe, to help things cool.

That all being said....there's a lot of comments in the Smoke forum about putting EVERYTHING outside- batteries, inverters, etc. That's fine an well but LiFePo4 aren't to be exposed to below freezing temperatures and I'm surely not paying for some heater.

This is probably and entirely different topic.....protection from Battleborn battery fires.

 

[OffGridForGood]

I spent quite a bit of time in the front end of this process looking at the battery chemistry, and risks.
I had this preconceived notion about Li-ion and fires - from the media, but quickly learned the differences between all the various Li- stuff battery types and that LiFe PO4 is one of the lowest risks.
I moved on and am not very concerned about the cells, 'The Offcial Solar Tester' running the system up to 17,000W all at once, yeah that I pay more attention to !

 

[pda1]

Mein Gott!!!! 53kW LiFePo4 That's A LOT of power

 

[OffGridForGood]

Mein Gott!!!! 53kW LiFePo4 That's A LOT of power

Not ENOUGH!
I have cells on order for another 15.5kWh pack, and space in my rack for one more after this next one...yeah will bring me up to 84kWh in the Spring of 2024. And that will still not be enough!! I wish I had a V2L EV, erg, oh well it will come eventually.
I have a formula to work out exactly how much ESS I need, here is the equation:
ESS capacity I have, x MORE = STILL NOT ENOUGH

 

[pda1]

The sad part is I've realized my solar batteries will probably out live me.

 

[timselectric]

The sad part is I've realized my solar batteries will probably out live me.

It's ok.
A lot of us are in that age group. lol

 

[pda1]

But....the good part is I file for Social inSecurity next month.....

 

[OffGridForGood]

I just stopped having birthday's - so I don't get a year older each year.

 

[OffGridForGood]

The sad part is I've realized my solar batteries will probably out live me.

Don't feel bad, I plant trees that I likely will not see to maturity, but I do it anyway!

 

[timselectric]

I just stopped having birthday's - so I don't get a year older each year.

I just celebrated the same birthday, for a second time.
You know that you are getting old, when you forget how old you are.
But on a good note, I was wrong last year. So, I'm younger than I thought. lol

 

[webbbn]

There are always more levels of protection, that can be applied. But you have to weigh the likelihood against the cost and effort.
Enough Voltage can create a arc across a gap. And enough amperage can sustain the arc.
Too much amperage on a conductor will create excessive heat.
Both of these conditions can cause a fire.
My point is that a battery built in a wooden box or frame, isn't a problem. As long as it's done properly.
Can you build your system in an underground concrete bunker, and feel safe? Yes
Can I build my system in my bedroom and feel safe? Absolutely.
You don't have to be afraid of electricity, but you do have to respect it.

Fair enough, but I wasn't referring to wooden boxes, where there is significant distance from the connectors to wood, but busbars and whatnot screwed to wood, where (at least in some pictures) it seems that the contacts are very close to the wood. It's convenient to just screw a sheet of plywood to the wall and screw everything to it, but it doesn't cost much to put some form on non-flammable layer on top of it. At least it makes me feel safer.

 

[webbbn]

I just celebrated the same birthday, for a second time.
You know that you are getting old, when you forget how old you are.
But on a good note, I was wrong last year. So, I'm younger than I thought. lol

I lost track of the number of times that I have celebrated my 29th birthday a long time ago, but now I'm like a kid again, just counting in reverse to retirement.

 

[timselectric]

I lost track of the number of times that I have celebrated my 29th birthday a long time ago, but now I'm like a kid again, just counting in reverse to retirement.

That was the downside of my birthday mistake.
I'm one more extra year from retirement. lol

 

[JJJJ]

one more extra year from retirement

What’s that? Hope I never grow up

 

[JJJJ]

Common house wiring is attached to or fished through wooden structures. No fire risk.

Difference is that DC is constant aka direct current. Things that will cause trouble is taking shortcuts with wire size; fuses and allowing poor connections which can allow arcing.

Metal raceways allow for a clean look but will not protect from poorly constructed systems. Open wires actually permit spacing and airflow. Not better but certainly not a safety hazard.

 

[OffGridForGood]

Common house wiring is attached to or fished through wooden structures. No fire risk.

and it is safe because the wire sizes are large enough and the breaker sized to protect those wires from overheating if they do see excess currents (which they shouldn't see if sized properly for their use). so we should learn and do the same for our solar set ups. Size wires properly for the loads, use fuses and breakers to protect those wires from excess heat under load.

 

[webbbn]

and it is safe because the wire sizes are large enough and the breaker sized to protect those wires from overheating if they do see excess currents (which they shouldn't see if sized properly for their use). so we should learn and do the same for our solar set ups. Size wires properly for the loads, use fuses and breakers to protect those wires from excess heat under load.

Not to belabor the point, but it's relatively easy to size wires correctly, and the fuses and breakers will protect those, but fuses and breakers will likely not protect against a failing connection. At 200A, it only takes 0.025 ohms of resistance in a loose connector to produce 1kw of heat. It's even worse if it arcs.

 

[timselectric]

A failed connection falls under improper installation.
There are a lot of what if's that can happen. You just have to pick which ones you are more concerned about.
What if there were an earthquake.
If the battery fell over. I would much rather have the terminals contact wood, than metal.
I purposely avoided any conductive materials around my batteries. My biggest concern would be a short across one cell. But I'm not going to place a fuse on each individual cell.

 

[webbbn]

A failed connection falls under improper installation.
There are a lot of what if's that can happen. You just have to pick which ones you are more concerned about.
What if there were an earthquake.
If the battery fell over. I would much rather have the terminals contact wood, than metal.
I purposely avoided any conductive materials around my batteries. My biggest concern would be a short across one cell. But I'm not going to place a fuse on each individual cell.

A connection can fail for many reasons (faulty manufacturing, stress fractures, etc), but, yes, it is likely due to improper installation. That's not a reason to argue against it. There are many non-combustible materials other than metal. I wouldn't recommend metal either, for obvious reasons. A thin sheet of drywall, even though it's paper covered, would be better than wood.

I'm sorry, but I really don't understand why an electrician, of all people would be arguing against basic safety procedures that cost essentially nothing. I'm sure you're perfect and have never made a connection that's failed, but not everyone is so gifted, so avoiding easy and obvious safety concerns might help some.

Maybe I'm more sensitive to this because I live in a desert tinderbox. I suppose there are other places where wood don't catch fire if you blink at it.

FWIW, I almost had a house burn down due to a makeup mirror...

 

[JJJJ]

I also prefer installing in a non conductive setting. I do have doors that can be closed and locked if needed to protect from young curious minds if needed.