hwy17
Anti-Solar Enthusiast
Thanks to the zealous rigor of some this forum's members, I guess I am now obligated to seek an amount of FR-4 Garolite separator material that Amazon is now asking me if I'd like to pay for it in installments...
hwy17's Orion battery build
- Thread starter hwy17
- Start date
42OhmsPA
What's in a title?
Never heard of it, thanks for the info maybe I'll consider it for the next packs after I delete my flexible cutting board stock ?.
Did you check McMaster?
McMaster-Carr
McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
hwy17
Anti-Solar Enthusiast
I just figured out McMaster is the place about 15 minutes ago! and Amazon only let me cancel 1 of my 2 big pieces from them. Only a couple dollars lost on the blunder I think.
offgrid-curious
Solar Enthusiast
Did your LF304s come with two separators in each box? I’m not sure exactly what material it is, but I assumed it would be used between cells.
hwy17
Anti-Solar Enthusiast
They did and I see now that's no insignificant accessory. They're probably getting a much better deal on that FR-4 in China.
I'm buying more separator for under and around the bank since the case and compression are all going to be metal.
Nobodybusiness
Solar Sponge.
Looks like an Op amp.love your symbol for inverter
Works for me..
Seagal puts her nerd hat on...
An op-amp is a linear circuit that has two inputs which amplifies the difference between the +ve and -ve inputs. The symbol is like this..
An inverter (of the component type) is a digital circuit that has one input and one output. The output is the inverse digital signal to the output. So an input of 1 (typically +3.3V or +5V) would result in an output of 0 (0V). And vice versa. The symbol is like this...
??
Nobodybusiness
Solar Sponge.
Not sure if agreed upon symbol for Inverter or not.
I Usually use Visio.
Have to look and see.
Nobodybusiness
Solar Sponge.
42OhmsPA
What's in a title?
hwy17
Anti-Solar Enthusiast
One of the most catastrophic hazards I have in mind is an earthquake that could tip the toolbox over, with the cell terminals landing into the metal case. I'm gonna put kapton tape over them but that's not really a guarantee of protection.
For a single toolbox, the chances that an earthquake could even tip them over is pretty unlikely I think, with the 2x8 footprint of the compressed cell bank. But, I have an expansion plan that involves another toolbox of 16 cells on top of this one, which could easily tip if not secured.
My two securing options are either to bolt the box to the concrete floor, or bolt it to the wood stud wall. Wood stud wall is a lot easier, but it puts the case up in direct wood contact which is a fire concern. Cells venting and catching on fire is I think one of the most unlikely scenarios.
Considering two boxes on top of each other, I'm not actually sure which is stronger. If the first one is bolted to the ground and the second one is bolted to the first one, that's a lot of lifting force on the bottom one's concrete anchors with 200lbs 2ft off the ground moving back and forth.
I could bolt to the studs with a layer of drywall in between, but man I hate working with drywall. And as bad as drywall is, cutting concrete fiberboard is even more of a PITA.
For a single toolbox, the chances that an earthquake could even tip them over is pretty unlikely I think, with the 2x8 footprint of the compressed cell bank. But, I have an expansion plan that involves another toolbox of 16 cells on top of this one, which could easily tip if not secured.
My two securing options are either to bolt the box to the concrete floor, or bolt it to the wood stud wall. Wood stud wall is a lot easier, but it puts the case up in direct wood contact which is a fire concern. Cells venting and catching on fire is I think one of the most unlikely scenarios.
Considering two boxes on top of each other, I'm not actually sure which is stronger. If the first one is bolted to the ground and the second one is bolted to the first one, that's a lot of lifting force on the bottom one's concrete anchors with 200lbs 2ft off the ground moving back and forth.
I could bolt to the studs with a layer of drywall in between, but man I hate working with drywall. And as bad as drywall is, cutting concrete fiberboard is even more of a PITA.
42OhmsPA
What's in a title?
42OhmsPA
What's in a title?
Is there any room at the top to add some sort of padding for additional protection?
I would run additional support, maybe strut, on the backside that joins the 2 boxes. Fasten the bottom to the concrete and the additional support to the wall.
If there is any earthquake that severe you'll more than likely have bigger problems to deal with...
Yes, exactly
... when referring to digital electronics a NOT gate is also called an inverter. The 7404 chip contains 6 of them, hence referred to as a hex inverter by the chip manufacturers.The point (=joke) I was making in post #2 and #4 (https://diysolarforum.com/threads/hwy17s-battery-build.72380/post-917485) was that @hwy17 used a NOT gate / digital inverter symbol rather than a
hwy17
Anti-Solar Enthusiast
Yeah good idea. I could put some HDPE up there if I figure out how to bolt or adhere it.
Like the propane water heater adjacent to my battery bank... If I end up on the news there will be one hell of a thread about it!
Nobodybusiness
Solar Sponge.
Gotcha. I’m slow. ?Yes, exactly
The point (=joke) I was making in post #2 and #4 (https://diysolarforum.com/threads/hwy17s-battery-build.72380/post-917485) was that @hwy17 used a NOT gate / digital inverter symbol rather than asymbol
hwy17
Anti-Solar Enthusiast
Unistrut mounted to the studs and then boxes mounted to the struts is a nice idea. But another research project for me to figure out strut bolts.
hwy17
Anti-Solar Enthusiast
I'm planning to use a pack split fuse, with a class T between cells 8 and 9. The Orion JR2 uses split cell management interfaces so this will not affect voltage readings and the passive balancers.
It's at the edge of my electrical understanding though whether a resistor in the middle of a bank affects the balance of charging. On one hand the resistor affects current equally across the whole circuit, but afaik voltage does drop in a gradient along the circuit.
So does that mean in any series of cells the last cells on one end are always getting a different voltage, resulting in an inherent imbalance force, which will be worsened by an added resistor in the middle of the string? I really don't know.
It's at the edge of my electrical understanding though whether a resistor in the middle of a bank affects the balance of charging. On one hand the resistor affects current equally across the whole circuit, but afaik voltage does drop in a gradient along the circuit.
So does that mean in any series of cells the last cells on one end are always getting a different voltage, resulting in an inherent imbalance force, which will be worsened by an added resistor in the middle of the string? I really don't know.
Why?
IMHO it wouldn't affect charging as the current through all cells would be the same. At the end of the day, every bus-bar connection is a small value resistor.
However, if there was a measurable voltage drop over that resistance, that would affect the cell balancing. The BMS will be measuring the cell voltages and an extra resistor that is only in series with one cell (either cell 8 or 9 depending on which side of the resistor you connect the balance lead) would result in that cell reading a bit higher than the actual cell's voltage is.
Obviously any voltage drop will be linear to current flow and may be immeasurable anyway.
hwy17
Anti-Solar Enthusiast
Mostly I find it a neat and convenient mounting location, and saves me having to buy a holder and mount the holder inside the case and the extra cable the holder adds. On top of that, I like that it protects some direct short circuits of the terminals.
Good, that is my hope.
I believe I won't be affected by this as the Orion JR2 uses separate cell interfaces for 1-8 and 9-16, with a negative tap on the terminal after the fuse on cell 9 to start the second interface's reading. Orion approves fusing at this specific midpoint.
hwy17
Anti-Solar Enthusiast
I have 3 thermistor taps on the BMS and they come in a free hanging probe or terminal mount.
I'm thinking maybe 2 terminal mounts at either end of the pack and one free hanging taped to the back side that's closest to the cold/hot exterior wall.
I'm thinking maybe 2 terminal mounts at either end of the pack and one free hanging taped to the back side that's closest to the cold/hot exterior wall.
hwy17
Anti-Solar Enthusiast
The toolbox arrived, the first one got delayed so I ordered another and then they both showed up. I don't like needlessly returning heavy items, so I think I'll just build it now as more expansion room. Also got one of the chinese clear case electrical boxes off amazon to house the BMS, bus bars, relays, and contactors. Kind of a mental tug of war where to put the main bus, but I think it's gravitating up and to the left near to the inverter. This controls box will get mounted to the top(front) of the server rack battery for now.
hwy17
Anti-Solar Enthusiast
I am honored that Digikey held my order up to confirm if this is for a company or I really ordered all this stuff for personal use.
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