Battery Boxes

[Lt.Dan]

Hey everybody, I have a dilemma of trying to find battery boxes for DIY packs, that fit all the various sizes of cells/packs that I have. The last one I did, with the Milwaukee packout box here, it worked great. But the packout boxes don't really work for anything other than the 4s 280ah cells.

I have cells and packs in every shape and size, and every aH available (almost).

Does anybody have any leads on a company or supplier that cells decent battery boxes in different sizes?

 

[Lt.Dan]

Some of the cells/packs that I have, some are just raw cells, some are packs robbed out of complete batteries

 

[meetyg]

Aliexpress is your friend...
Seriously now, I bought a variety of battery boxes on Aliexpress (and one time on Alibaba).
You can simply search "battery box" on Ali.
Here are some examples that I actually got:

https://www.aliexpress.com/item/1005002704269294.html

https://www.aliexpress.com/item/1005003229230174.html

https://www.aliexpress.com/item/4000195674596.html

They have various sizes, so just look around on the seller's store.

I did have a struggle finding the smallest box for an 8s 24v Lifepo4 build, using EVE LF90K Cells (same dimensions as the more common LF105). The real problem was thier height. The only boxes that would fit were designed for 4s 280Ah Cells. But these were too wide for my needs. So after searching and buying various boxes, I ended up buying a standard box that would fit the cells and had a friend at work 3d print an extension to the lid. Worked out pretty well.

 

[SeaGal]

How about some 4' x 8' plywood sheets and a table saw? ???

(nice battery pics, btw!)

 

[Lt.Dan]

Aliexpress is your friend...
Seriously now, I bought a variety of battery boxes on Aliexpress (and one time on Alibaba).
You can simply search "battery box" on Ali.
Here are some examples that I actually got:

https://www.aliexpress.com/item/1005002704269294.html

https://www.aliexpress.com/item/1005003229230174.html

https://www.aliexpress.com/item/4000195674596.html

They have various sizes, so just look around on the seller's store.

I did have a struggle finding the smallest box for an 8s 24v Lifepo4 build, using EVE LF90K Cells (same dimensions as the more common LF105). The real problem was thier height. The only boxes that would fit were designed for 4s 280Ah Cells. But these were too wide for my needs. So after searching and buying various boxes, I ended up buying a standard box that would fit the cells and had a friend at work 3d print an extension to the lid. Worked out pretty well.
View attachment 165193View attachment 165194View attachment 165195View attachment 165196View attachment 165197

I will look into these more. I did for a little bit, but I could only find boxes that were like 1" too narrow, or wayyy too big, or they were a good price, but $200 to ship it. Like what the hell.

Anybody else have ideas?

 

[SilverbackMP]

How about some 4' x 8' plywood sheets and a table saw? ???

(nice battery pics, btw!)

Or a track saw; preferably outfitted with TSO parallel clamps and other jigs. My joints are too old to be wrestling 4x8 sheets of 3/4 on a table saw. I like it so much I am going to build a dedicated track saw bench that will have dogs and a track hinge.


I did try to find ready made solutions, but I had painted myself into a corner with sizing.

 

[42OhmsPA]

Why not pick up some 1x rough cut, do you have any Amish lumber yards / saw mills near by? You could order it to width...
I'm thinking of going this route more and more, haven't used the pocket hole jig in a while.

 

[SilverbackMP]

Why not pick up some 1x rough cut, do you have any Amish lumber yards / saw mills near by? You could order it to width...
I'm thinking of going this route more and more, haven't used the pocket hole jig in a while.

Not sure if you are replying to me, but rough cut straight from the mill is green so it needs about a year per inch to air dry.

We actually have both. Amish saw mills that cut rough hardwood (usually pallet material but you can place an order for anything) and lumber yards that sell regular dimensional construction materials at low prices.

Plywood makes much more sense for something like this. I used 5-6 ply birch (not Baltic birch which is now close to unattanium) but construction grade would work ok too.

I tried straight pocket holes for this. Not quite strong enough so you see the counter sinked wood screws on the edges that I added after the fact.

I suppose if one really wanted to go above and beyond, box jointed hardwood would be neat, but I lined my boxes with 1/4 inch rubber floor mat material (for both electrical resistance and as part of cell compression) and would want to negate movement.

You can see the lining here:

 

[42OhmsPA]

Not sure if you are replying to me, but rough cut straight from the mill is green so it needs about a year per inch to air dry.

We actually have both. Amish saw mills that cut rough hardwood (usually pallet material but you can place an order for anything) and lumber yards that sell regular dimensional construction materials at low prices.

Plywood makes much more sense for something like this. I used 5-6 ply birch (not Baltic birch which is now close to unattanium) but construction grade would work ok too.

I tried straight pocket holes for this. Not quite strong enough so you see the counter sinked wood screws on the edges that I added after the fact.

I suppose if one really wanted to go above and beyond, box jointed hardwood would be neat, but I lined my boxes with 1/4 inch rubber floor mat material (for both electrical resistance and as part of cell compression) and would want to negate movement.

You can see the lining here:

View attachment 165892

I was giving Dan what I thought was a good idea for "boxes" but you pointed out multiple good reasons it wouldn't be, thank you. Good info on the pocket holes too.
Fortunately I have some 1x12s that have been on my rack for about 4 years so I'll likely be going that route and welding up a frame to hold them.
I've seen your boxes before and really like how they turned out and how you were able to incorporate the class T into the box. I'm using JBDs with contactors built in so that's one less thing I have to worry about fitting.

 

[SilverbackMP]

I was giving Dan what I thought was a good idea for "boxes" but you pointed out multiple good reasons it wouldn't be, thank you. Good info on the pocket holes too.
Fortunately I have some 1x12s that have been on my rack for about 4 years so I'll likely be going that route and welding up a frame to hold them.
I've seen your boxes before and really like how they turned out and how you were able to incorporate the class T into the box. I'm using JBDs with contactors built in so that's one less thing I have to worry about fitting.

OMG, the time spent trying to fet up the first prototype box lol. I wouldn’t advise anyone copying these boxes unless they fit specific space requirements. I would go with Ray’s box design (Ray Builds Cool Stuff) or the design from that Canadian female that was doing the electric boat conversion (can’t find her channel or remember her name).

More room to to work in.

I do like my compression for KISS. Cells individually wrapped in Kaptom tape, then a group of eight lightly compressed with bar clamps and then three rows of strapping tape to hold them together, and then the rubber liner providing a little more compression force spread. In some of my boxes, the groups of eight cells required a little persuasion to slide in and a few that were a little looser I shimmed with sheets of flexible cutting mat material (Dollar Store has them).

No calculations required, no crazy mechanisms, and I suspect it is good enough.

 

[rhino]

Canadian female that was doing the electric boat conversion

The Digital Mermaid. Maybe referring to this video of her building it?

 

[SilverbackMP]

The Digital Mermaid. Maybe referring to this video of her building it?

Yep, that be she.

 

[Skypower]

Well if you do decide to build your own, now would be a good time (excuse) to buy a good portable table saw if you don’t already have one. I have a DeWalt and after a few tweaks of alignment I can slice wood like I’m making cabinetry. Radiata pine(2’x4’ hobby sheets, Home Depot) has thicker veneer and less likely to shear. Use Titebond 3 glue (can’t use too much). Test run a clamp up. Clamp up, screw and use hardwood dowels for the end alignment before gluing since scooting things with glue on is impossible and screws surprisingly are poor alignment, yeah, the glue is that fast. I use two modules of eight because that’s about my limit for lifting. The floor unit has a separate base with rollers that the modules locate on. The module jumpers should have the same resistance as the busses.

 

[rodrick]

Check out some of the larger army surplus stores they have many different size ammo cans and equipment boxes

 

[Skypower]

Check out some of the larger army surplus stores they have many different size ammo cans and equipment boxes

Man, I didn’t even think of that?

 

[Rednecktek]

How are your welding skills?

I'll let you know how it turns out.

 

[SilverbackMP]

Well if you do decide to build your own, now would be a good time (excuse) to buy a good portable table saw if you don’t already have one. I have a DeWalt and after a few tweaks of alignment I can slice wood like I’m making cabinetry. Radiata pine(2’x4’ hobby sheets, Home Depot) has thicker veneer and less likely to shear. Use Titebond 3 glue (can’t use too much). Test run a clamp up. Clamp up, screw and use hardwood dowels for the end alignment before gluing since scooting things with glue on is impossible and screws surprisingly are poor alignment, yeah, the glue is that fast. I use two modules of eight because that’s about my limit for lifting. The floor unit has a separate base with rollers that the modules locate on. The module jumpers should have the same resistance as the busses. View attachment 165903View attachment 165904

One reason I didn’t go with glue (I did on bits and pieces), was being able to disassemble if I needed to ever replace a cell. My initial pocket holes were on the exterior (on the sides) rather then on the interior. May or may not be an issue depending on design, but something to keep in mind.

 

[Skypower]

One reason I didn’t go with glue (I did on bits and pieces), was being able to disassemble if I needed to ever replace a cell. My initial pocket holes were on the exterior (on the sides) rather then on the interior. May or may not be an issue depending on design, but something to keep in mind.

Yeah, no matter how well you plan, you gotta plan for the what if’s. My cells are removable, I just have to turn the spring compression bolt. If you do remove after they’ve been used, it’s best to so at a low state of charge and cool. I did this when I went away from 2 cells in parallel. Balancing those cells once separated was a whole lotta fun? but successful. They had worked out some sort a personality when together, like you do the work at this state of charge and I’ll catch it later.

 

[Lt.Dan]

How are your welding skills?

I'll let you know how it turns out.

Lol, I manage a full fledged CNC Laser and WaterJet shop, as well as doing high end custom fabrication. With all the equipment and skills I have, I STILL chose to buy the 3x 280ah Mason kits, rather than make them. Lmao

I also like the idea of a plastic box, rather than metal. I've made a couple metal battery boxes in the past. And they just require so much more details and extras.

 

[Alkaline]

Yeah sorry when you can get these metal cases with bms for around 400-500 I would say a big no to the wood boxes.

ALSO its wood after all not the best material for a battery box...