Pulled the trigger, need a box...

[Supervstech]

I have been experimenting with several boxes lately.
I like the tall milwaukee square box.
Also the packout system job box is nice.
On the cheap end, I picked up a Plano box at home depot yesterday, nice size $12
Lotsa options in plastic boxes.

 

[RoySalisbury]

3D printed mine with aluminum end caps. Not quite done...need to wire up the BMS. There is a cover that goes over the BMS case. Those are insulator pieces between the cells. There are people that put their cells against each other with no insulators...that's a bad move in a mobile environment.

Did you 3D print the top and the bottom bracket for each cell? I was thinking of doing the same thing after I saw the fourtune cells (they have them built in). If you have the STL file and would like to share it would be appreciated.

Roy

 

[JeepDaddy]

27 Series Marine battery box, about $10 as shown here: My Build.....

 

[brb58]

Did you 3D print the top and the bottom bracket for each cell? I was thinking of doing the same thing after I saw the fourtune cells (they have them built in). If you have the STL file and would like to share it would be appreciated.

Roy

I used this guy's design and yes, you print top and bottom.

280ah Battery Top and Bottom Support Design.

I'm planning to build a couple 12v batteries using the 280ah cells. Every since seeing the Fortune batteries on a couple of Wills videos I have been thinking about making my own pieces on my 3d printer. This is my current design. I'm thinking of using Lego like features to allow a top cover...

diysolarforum.com

This is the Thingiverse link

EVE 280ah Battery Supports by Heap64

These supports can be used to join EVE 280ah Lithium Cells to make a battery using 1/4" threaded rod. With these you will need to make or source your own busbars with holes 80mm on center. The end plates were designed to also use the same busbars.

www.thingiverse.com

Now that I am slightly proficient in Fusion 360, I can now make my own. The case for the JBD BMS on the end is my design.

Since I was using the 280AH Eve cells, using his design was a no brainer. I couldn't print the endcaps since they were too large for my Prusa MK3s. The aluminum actually works out fine. I just bought some aluminum remnants from a metal supply place and cut them to size with my plasma cutter.

Here is my BMS case. I take the stock 3mm screws out of the BMS and use some long 3mm screws to mount the BMS from the backside.

 

[RoySalisbury]

I used this guy's design and yes, you print top and bottom.

Thanks. I'll take a look at them.

I was also going to use Fusion 360. I have to create some for some EVE 230 cells first (don't have the 280's yet). I'll try to remember to post a link to my Fusion files when I am done.

Roy

 

[RoySalisbury]

Decided to just create my own battery terminal "protector" from scratch. This is the first draft. It just covers the terminal and provides about a 2.5mm spacing between batteries. I will also need to print something for the bottoms as well.



As soon as I print a few more I will post an image of what they look like on the batteries. These are for the EVE 230's.

 

[RoySalisbury]

As soon as I print a few more I will post an image of what they look like on the batteries. These are for the EVE 230's.

Still need to account for the BMS wire routing, but they work pretty good and makes things a bit safer. They "fix" the batteries in place (to releive stress on the terminals), and allow for the recommended swelling of the batteries

 

[curiouscarbon]

Still need to account for the BMS wire routing, but they work pretty good and makes things a bit safer. They "fix" the batteries in place (to releive stress on the terminals), and allow for the recommendedView attachment 96621 swelling of the batteries


View attachment 96620

nice solution! thanks for sharing ?

 

[brb58]

Why

Still need to account for the BMS wire routing, but they work pretty good and makes things a bit safer. They "fix" the batteries in place (to releive stress on the terminals), and allow for the recommended swelling of the batteries

Why let them swell at all? Print up some spacers. Put some area on the sides to clamp together or do you have another method to do that?

 

[740GLE]

Are those bus bars maxed out for width?

 

[curiouscarbon]

Why

Why let them swell at all? Print up some spacers. Put some area on the sides to clamp together or do you have another method to do that?

preventing cell wall flexure is a goal of mine with builds involving large format cells (>250Ah) as well as not inducing internal overpressure from excessive fixture force.

however, has anyone documented/demonstrated that the corners will eventually crack from repeated flexing?

sorry if this is a silly question.

 

[RoySalisbury]

Why let them swell at all? Print up some spacers. Put some area on the sides to clamp together or do you have another method to do that?

From what I have read/watched on youtube, there is confusion about "compressing" and "fixing". My Understanding is that you dont need to "compress" them. They just need to be fix in place so that if they do swell then they dont put stress on the terminals. By giving them the indicated room to expand (0.5 mm) then you no longer have stress on the terminals.

I was originally going to "compress" them, but all indications are that thats not whats actually needed. I could be wrong.

 

[RoySalisbury]

Are those bus bars maxed out for width?

Pretty much .. I could get perhaps another 2 mm out of them .. Right now I have the cells separated by about 3mm.

 

[brb58]

From what I have read/watched on youtube, there is confusion about "compressing" and "fixing". My Understanding is that you dont need to "compress" them. They just need to be fix in place so that if they do swell then they dont put stress on the terminals. By giving them the indicated room to expand (0.5 mm) then you no longer have stress on the terminals.

I was originally going to "compress" them, but all indications are that thats not whats actually needed. I could be wrong.

Mine aren't compressed per se. There really is no room in my fixture to compress. They are just clamped to eliminate any bloating.

 

[curiouscarbon]

From what I have read/watched on youtube, there is confusion about "compressing" and "fixing". My Understanding is that you dont need to "compress" them. They just need to be fix in place so that if they do swell then they dont put stress on the terminals. By giving them the indicated room to expand (0.5 mm) then you no longer have stress on the terminals.

I was originally going to "compress" them, but all indications are that thats not whats actually needed. I could be wrong.

• stress on terminals from flexture
• stress on cell aluminum wall from flexture

these two factors seem to be conflated in some discussions!

my gut does indicate that the terminal lateral force will cause "more damage per cycle" than the cell wall shape change.
the geometry of shearing a post laterally (cell terminal force) vs flat plane with low radius cylindrical deformation (cell wall).

however, this is complete speculation!

 

[740GLE]

Pretty much .. I could get perhaps another 2 mm out of them .. Right now I have the cells separated by about 3mm.

What state of charge are the cells in pictures?

 

[RoySalisbury]

What state of charge are the cells in pictures?

100% .. or as close to it as I can get without balancing each cell exactly. So say 98-100 ...

 

[WYtreasure]

Ya best get your butt off that boat for good.

I'll go back and read the other 36 posts some other time. Just wanted to share the fact you made me laugh out loud.
The title of the thread should have been "How on earth am I going to (get my wife to) keep these damn things from freezing". I'm laughin' to tears.

 

[brb58]

Ya best get your butt off that boat for good.

I'll go back and read the other 36 posts some other time. Just wanted to share the fact you made me laugh out loud.
The title of the thread should have been "How on earth am I going to (get my wife to) keep these damn things from freezing". I'm laughin' to tears.

I am so confused.

 

[Rednecktek]

I am so confused.

I work on ships and have pretty much been stuck at sea for the last year. My camp and house regularly see sub-freezing temps for months on end which really prevents me from playing with LFP batteries.. I've had a LOT of problems trying to get solar to play nicely over the years.

Fortunately the "Practice Box" will probably end up in my brother's pop-up trailer and since he just throws it on the charger before and after Memorial and Labor day camping trips, it should survive just fine... I hope... Also got some cheaper 200Ah guys that are a little more expendable... just in case...