Home built battery box, G10-FR4 1/4 inch cover over terminals with BMS on top?

[12kw_2021]

Hello

I am finishing up a 280Ah 12v build with a group 27 battery box. I would like to save some length and installl the 200A JBD BMS on the top of the cells. Two options, one build an inverted U shape with 1/4 G10-FR4 Fire resistant material, and attach the BMS to the "roof" of the inverted U. The Material is non conductive and will support the BMS and keep it from shorting the top exposed internal battery posts and bus bars. I could build the U shape to completely clear the battery posts, but then the battery case height will need a small extension. (more complex)

Simple option

Second option is to just drop a sheet of the same material on top of the battery posts that I could add rubber stoppers to to eliminate friction, and then mount the BMS on top of this "cover plate".

This is going in an RV, and so it will be bouncing down the road

Any feedback for a rookie from the experts here? I see folks using plywood as battery ends, but I also saw the thread where a wood material cover started a fire, and I so I would like to minimize any flammable materials inside my plastic case.

Thanks in advance for feedback/suggestions.

 

[NVS]

I would like to see pictures and a Link to the battery box you are using.

 

[12kw_2021]

I am using a simple walmart plastic bothx group 24-31, $14.00. I am chopping off one end and then sliding the cut portion into the longer remaining portion so that when I install 2 of these boxes they will fit in the 28 inches of allowed total space under my steps where the current wet batteries are placed. The bottom of that storage area is exposed to the elements so having a plastic surround the batteries is needed.

I am drilling holes and using nylon 1/4x20 bolts and nuts to hold the two portions together, then filling in the cracks with Silicon Sealant that is rated for freezing and wet exposure. It is not an elegant solution, but it works . The separate top cover will also need to be cut to fit the new reduced length box. Used nylon bolts to avoid any metal bolts that may protrude slightly then rub on the edges of the batteries inside the case.

I debated some kind of compression, and decided that for my application, it was not worth the extra effort. I am inserting thin plastic "Cutting Mats" as an insulator between each battery. Those are 50 cents each at the dollar store. I will use Kapton Tape wrapped around the batteries to hold the 4 cells together.

All of the battery tear downs I see online have the BMS placed above the batteries , so I am removing 4 3mm screws that hold the heatsink on the JBD 200A BMS, and then using longer nylon 3mm screws to go through the 1/4 inch thick G10 FR4 material to secure the BMS on the top of that material, then I will place the fire resistant insulation plate on top of the battery posts, and use tape , or velcro to secure it in place on top of the exposed posts. The F10 FR4 material is large enough to cover all of the battery terminals, so when complete only the 2/0 cables connecting the battery will be exposed.

Here is a link to the inexpensive box I am modifying. (They sell one other smaller size battery box, but it is not large enough for 4 208AH cells.)

Robot or human?

I've attached images of the partial build.. note that the current 3mm screws that penetrate the insulating material are metal, and I don't want them to be exposed facing down towards the battery posts, so those will be replaced with nylon 3mm screws.

Goal is no metal from case anywhere near the battery.