Diy ply battery box

[terry82517]

Thinking of making a battery box out of 18mm ply for my eve cells and bms.
good idea? or can anyone think of any problems with a ply box instead of normal plastic?
I plan to make lots of vent holes.

 

[HRTKD]

I used 3/4" plywood to make the compression frame for mine. As long as your box can handle the compression stress, it should work.

 

[Steve_S]

This is my 24V/280AH Square Pack boxes I made up.
I use Chargery BMS which sits external to the box.

Here is my 280H Block Pack boxes, made with 3/4" PureBond Plywood (left over from some cabinet making I was doing).
This provides a very Snug Fit for the cells.
The cells are bound anyways to prevent expansion when being charged.
There is orange Nylon Pull Strings to help make it easier IF a bundle of 4 as to be yanked out of the box.
Lugs attached to cells have 1/4" hole to match cell bolts, 3/8's hole attaching to battery terminal on box.

* REVISIONS Oct.2020:
I am replacing the Ply top with a hinged clear acrylic top so I can see inside the packs.
Replacing BMS Harness with new 14Ga wire, as I am installing a QNBBM 8S Active Balancer into each pack that is far more Amperage output than Chargery Passive Balancing (which will be disabled). The new QNBBMS will fit into that "slot" between the cell divider and box front with room to spare front & back of the board.

REFERENCE Links to products in use:
Purebond Plywood: https://purebondplywood.com/
Kreg Pocket Hole Jig (I use an R3): https://www.kregtool.com/shop/pocket-hole-joinery/pocket-hole-jigs/
Chargery BMS8T: http://www.chargerystore.com/index.php?route=product/product&path=20_26&product_id=86
Chargery DCC 300A: http://www.chargerystore.com/index.php?route=product/product&path=62&product_id=66
QNBBM 8S Active Balancer: https://deligreen.en.made-in-china....tteries-Pack-Equalizer-Voltage-Balancing.html



Assembled Box below and to the right with 280AH cells BusBars & BMS harness in place.

 

[terry82517]

I used 3/4" plywood to make the compression frame for mine. As long as your box can handle the compression stress, it should work.

Any pictures please? Does it have to be very tight?

 

[terry82517]

This is my 24V/280AH Square Pack boxes I made up.
I use Chargery BMS which sits external to the box.

Here is my 280H Block Pack boxes, made with 3/4" PureBond Plywood (left over from some cabinet making I was doing).
This provides a very Snug Fit for the cells.
The cells are bound anyways to prevent expansion when being charged.
There is orange Nylon Pull Strings to help make it easier IF a bundle of 4 as to be yanked out of the box.
Lugs attached to cells have 1/4" hole to match cell bolts, 3/8's hole attaching to battery terminal on box.

* REVISIONS Oct.2020:
I am replacing the Ply top with a hinged clear acrylic top so I can see inside the packs.
Replacing BMS Harness with new 14Ga wire, as I am installing a QNBBM 8S Active Balancer into each pack that is far more Amperage output than Chargery Passive Balancing (which will be disabled). The new QNBBMS will fit into that "slot" between the cell divider and box front with room to spare front & back of the board.

REFERENCE Links to products in use:
Purebond Plywood: https://purebondplywood.com/
Kreg Pocket Hole Jig (I use an R3): https://www.kregtool.com/shop/pocket-hole-joinery/pocket-hole-jigs/
Chargery BMS8T: http://www.chargerystore.com/index.php?route=product/product&path=20_26&product_id=86
Chargery DCC 300A: http://www.chargerystore.com/index.php?route=product/product&path=62&product_id=66
QNBBM 8S Active Balancer: https://deligreen.en.made-in-china....tteries-Pack-Equalizer-Voltage-Balancing.html

View attachment 24149View attachment 24150

Assembled Box below and to the right with 280AH cells BusBars & BMS harness in place.
View attachment 24151View attachment 24152

this is perfect Thankyou. Was planing on using pocket holes to build mine too, was thinking of putting in a devider in to separate the bms.
What is the advantage of having the bms outside the box please?

 

[Steve_S]

The Chargery BMS is NOT like others due to it's casing and configuration. There is a USB port to update the firmware and such which access is needed. The LCD Control module is also attached via wire to the main module. Also a Passive Balancer, they can get pretty warm when burning off the high voltage cells. The Active Balancer (QNBBM) also warms but not the same and makes an unpleasant squeal when active.

 

[HRTKD]

Any pictures please? Does it have to be very tight?

See if this link works. It should go to post #191 in the thread. https://diysolarforum.com/threads/lifepo4-heating-pad-for-cold-temperatures.5/post-144036

I tightened each threaded rod to 24 inch lbs. That's not much, but across all four it adds up. My battery is compressed enough that I can pick it up by the threaded rod and the cells don't move.

 

[terry82517]

perfect thankyou for the reply they are all very helpful, would you think it would be ok to use 10mm (m10) threaded bar and bolts as bulkhead terminals?

 

[HRTKD]

perfect thankyou for the reply they are all very helpful, would you think it would be ok to use 10mm (m10) threaded bar and bolts as bulkhead terminals?

I don't know what you are asking. Can you explain?

 

[terry82517]

I don't know what you are asking. Can you explain?

in your photos you used bulkhead cable connectors, instead of these would it be ok to use threaded bar with bolts to clamp the lugs between?

 

[HRTKD]

in your photos you used bulkhead cable connectors, instead of these would it be ok to use threaded bar with bolts to clamp the lugs between?

I suppose you could. That's one way to join two cables of different gauge, without resorting to a butt connector/splice.

What you call "bulkhead cable connectors", I think we're called a bus bar. A plate of conductive metal (usually copper) with studs coming through the plate to attach cable lugs to. You may want to look at Junction Blocks as seen at the bottom of this page: http://www.fastronixsolutions.com/Terminal Products/Power Ground Terminal Blocks.htm.

 

[terry82517]

I suppose you could. That's one way to join two cables of different gauge, without resorting to a butt connector/splice.

What you call "bulkhead cable connectors", I think we're called a bus bar. A plate of conductive metal (usually copper) with studs coming through the plate to attach cable lugs to. You may want to look at Junction Blocks as seen at the bottom of this page: http://www.fastronixsolutions.com/Terminal Products/Power Ground Terminal Blocks.htm.

these are the blulkhead conectors https://www.carbuilder.com/uk/bulkhead-power-cable-connector.

 

[HRTKD]

I didn't use any of those, anywhere in my components. But if I did, I don't think I would be creating my own. I would use an off the shelf solution, just to play it safe.

 

[terry82517]

I didn't use any of those, anywhere in my components. But if I did, I don't think I would be creating my own. I would use an off the shelf solution, just to play it safe.

ah sorry it was somone else in this thread. yes you are rite, i will use the proper connections. thanks for your help.

 

[Pim57]

Using 18 mm plywood.


The cells just squeezed in. No need for threaded rods. Gently filing the locks until a tight fit.
The NTC thermistor sits in a hole with foam pushing it against the middle of the cell.

Clamping with pressure gives an increase in performance according to this article.

Analysis of the effect of applying external mechanical pressure on next generation silicon alloy lithium-ion cells

This research will focus on characterising and analysing next generation batteries consisting of silicon-alloy/graphite blend anode combined with a ni…

www.sciencedirect.com

need to finish with bolts etc.