First time DIY case

[hardtop]

I had originally drafted a case design and gave it to a plastic shop to build, but they fell through. Instead, I found plastic cutting boards as a material resource at a local restaurant supply store. They had blue cutting boards :D For this build I felt a bottom would be helpful so I don't drop the batteries out from not enough compression and I won't over-compress trying to squeeze the batteries so they stay together.

The threaded rods and nuts are stainless with galvanized washers. The screws are all stainless from Ace Hardware. I need to get cabling, an inverter, charger and a new BMS.

The JK BMS I got from the batterystore was DOA, so I ordered a Smart Jiabaida (JBD) 4S 12V 200Afrom srikobatteries.com. Once the new BMS is fit, another plastic piece will act as the top that slides in-between the sides to cover the terminals and to set the charger and inverter on top of.

 

[littleharbor2]

I'd recommend you slide sone non metalic tubing over the exposed treads of the all thread.

 

[42OhmsPA]

I'd recommend you slide sone non metalic tubing over the exposed treads of the all thread.

Agreed, I would also add insulators between the cells.

Nice build otherwise. Are you going to cut handles into the tops?

 

[hardtop]

Agreed, I would also add insulators between the cells.

Nice build otherwise. Are you going to cut handles into the tops?

That is a good idea, but I don't have the tool (Jigsaw) to create the holes. I'm planning on cutting up a 4" wide plastic piece to screw to the sides at the bottom for grips.

 

[JJJJ]

Once you add the top breathing is easier. Helps to prevent the incidental oops scenario which releases the magic smoke…

 

[740GLE]

Be mindful those cutting boards while seem stiff, will bend and flex over time, just keep an eye on them as they age.

 

[1201]

Agreed, I would also add insulators between the cells.

Nice build otherwise. Are you going to cut handles into the tops?

What are the insulators for?

 

[SparkyJJO]

What are the insulators for?

The thin blue wrapping is, well, thin. Some have had shorts occur between cells due to a weak point in the wrapper. Adding another insulating layer between cells prevents problems.

 

[1201]

The thin blue wrapping is, well, thin. Some have had shorts occur between cells due to a weak point in the wrapper. Adding another insulating layer between cells prevents problems.

Oh snap. No idea it was that thin. What's good and cheap to use for insulators?

 

[42OhmsPA]

The thin blue wrapping is, well, thin. Some have had shorts occur between cells due to a weak point in the wrapper. Adding another insulating layer between cells prevents problems.

Yup. I've seen enough up in smoke posts that didn't have insulators to convince me they were necessary reassurance. I also may have shorted out a cell terminal in my early days and had a puckering moment of realization as to how much energy is stored inside these cells.

 

[42OhmsPA]

Oh snap. No idea it was that thin. What's good and cheap to use for insulators?

I like these, made in USA. Arrow Home Products 10pc Flex Cutting Mat, White https://a.co/d/eaouxbb

 

[rhino]

Also this post: https://diysolarforum.com/threads/lifepo4-cell-separator-material.28023/

 

[Billwilson]

I am sure you have seen videos about the video about the twin screws busbars being bad has made it ever where the hump in the bus bars helps insure the bars fit flat so using both screws is wise and add a carbon paste on clean connections. the following image is a professional built pack the spacer is a little more understandable for cooling/heating and protection
.

 

[OffGridForGood]

That is a good idea, but I don't have the tool (Jigsaw) to create the holes.

-don't need a jigsaw: just a drill & hole saw. Drill series of hole-saw holes overlapping in a line, clean up the bits left between with a rasp/file/chisel.

 

[SparkyJJO]

Or, just buy the jigsaw. Good excuse to buy more tools.

 

[hardtop]

I am sure you have seen videos about the video about the twin screws busbars being bad has made it ever where the hump in the bus bars helps insure the bars fit flat so using both screws is wise and add a carbon paste on clean connections. the following image is a professional built pack the spacer is a little more understandable for cooling/heating and protection
.View attachment 186771

I haven't heard anything about the twin screw busbars. They are strange to me and I'm curious how they are allowing flex in the middle of the bar where the orange material is. I put all the bolts in, thanks for the suggestion.

The other suggestion about the rods I need to heed to but I may end up doing a v2 with more space between the rod and cell because I was concentrating on using the least amount of width as possible so I don't waste cargo space and put the rods a bit close.

This is a pic showing the rod clearance:

Or, just buy the jigsaw. Good excuse to buy more tools.

I went into Ace asking for something that can cut metal (threaded rod) and plastic (cutting board) and below is what the guy suggested. It worked on both materials. It vibrates to cut. It also has sanding discs so I could clean up the shoddy look from cutting the plastic with it lol.

 

[JJJJ]

Just make sure to check the contact surface of the bus bar with the battery. It may be necessary to trim away a small amount of the orange insulation on the battery contact side.

 

[NickC]

I like these, made in USA. Arrow Home Products 10pc Flex Cutting Mat, White https://a.co/d/eaouxbb

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https://a.aliexpress.com/_m0n399e

Or those

 

[littleharbor2]

English translation.

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[Billwilson]

English translation.

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