Polystyrene and foam in battery case

DipstickDash · Jan 10, 2022

Hi all.

I know it's not the prettiest build. It's my first time.

I have x4 280ah EVE cells with QUCC 120A BMS.

I found a decent sized heavy duty transport box for the battery to sit in but there was space around the side of the battery.

So I've added polystyrene to stop the battery from moving and rattling. My question is is this safe?

There is also foam already built on to the lid of the box. It's directly above the terminals almost touching, probably not ideal. I'm think I should remove the top foam add some holes at the tops for ventilation. Also connect & add some M6 post terminals outside the case.

Thoughts?

Bubba1 · Jan 10, 2022

Is this a mobile unit? If yes then it looks like they will eventually come loose. All that holds then together is the little bit of foam and the bus bars. I think you need a smaller box and better design, At least tape the cells together. Good luck

DipstickDash · Jan 10, 2022

Bubba1 said:
Is this a mobile unit? If yes then it looks like they will eventually come loose. All that holds then together is the little bit of foam and the bus bars. I think you need a smaller box and better design, At least tape the cells together. Good luck

Thank you

At the moment it will reside in my shed. I want it more secure to prevent shorting. Eventually it will go in my van.

Although the picture doesn't show clearly the cells are taped together tightly with gorilla tape. Both at the top and bottom of cells. I'm tempted to ratchet strap them together, though tbh I haven't looked in to that yet and I'm unsure if it's such a great idea.

I'm considering removing the busbars and adding 6 awg cables for more flexibility.

This is the case I intend on using, there is no movement at all in the box. I am more concerned whether the polystyrene is a hazard or not.

Pappion · Jan 10, 2022

I used yoga blocks. Very dense and easy to cut.

DipstickDash · Jan 10, 2022

Pappion said:
I used yoga blocks. Very dense and easy to cut.

Good idea!

Pappion · Jan 11, 2022

Your busbars are flat. Mine have a slightly raised curve to them. Making them better suited for temperature expansion and contraction

DipstickDash · Jan 11, 2022

Pappion said:
Your busbars are flat. Mine have a slightly raised curve to them. Making them better suited for temperature expansion and contraction

I am tempted to use 6awg cable I have seen a few people doing this, seems like a good idea.

Pappion · Jan 11, 2022

I used anti vibration padding on the bottom. Two layers.
anti vibration pad

curiouscarbon · Jan 11, 2022

DipstickDash said:
I am tempted to use 6awg cable I have seen a few people doing this, seems like a good idea.

hi!

with the big cells, i too am building with cable instead of busbar, due to cell physically "breathing" across 0-100% charge.

100A is the highest continuous from the 280/300Ah type cell i personally will design for (to be gentle to cell limits, and also overkill BMS limit), so one or two 6awg cable in a lug is what im thinking. 6awg should be good for ~50A at least and two should be good for about ~100A. im using silicone insulated tinned copper cable, which 6awg is biggest i could find. its really soft.

anyways, good luck, im sure you can figure out something good?

ElectricIslander · Jan 11, 2022

That's not polystyrene foam in the photos - looks more like expanded polyethylene (more like small bubble bubblewrap packing foam)

DipstickDash · Jan 11, 2022

curiouscarbon said:
hi!

with the big cells, i too am building with cable instead of busbar, due to cell physically "breathing" across 0-100% charge.

100A is the highest continuous from the 280/300Ah type cell i personally will design for (to be gentle to cell limits, and also overkill BMS limit), so one or two 6awg cable in a lug is what im thinking. 6awg should be good for ~50A at least and two should be good for about ~100A. im using silicone insulated tinned copper cable, which 6awg is biggest i could find. its really soft.

anyways, good luck, im sure you can figure out something good?

Thank you! It's all a learning curve for me at the moment

DipstickDash · Jan 11, 2022

ElectricIslander said:
That's not polystyrene foam in the photos - looks more like expanded polyethylene (more like small bubble bubblewrap packing foam)

Yes, I think you're correct I've always known it as and called it polystyrene. But it is the material which the cells arrived in.

I cut out to size, so the cells are sunk and sat in then I used the offcuts to wedge the cells in place to stop vibration and movement.

Am I gonna boom? ??

Alloy · Jan 11, 2022

DipstickDash said:
I am tempted to use 6awg cable I have seen a few people doing this, seems like a good idea.

Pappion said:
Your busbars are flat. Mine have a slightly raised curve to them. Making them better suited for temperature expansion and contraction

Only a concern if there was more than 6 cells connected in a row.

DipstickDash · Jan 11, 2022

Pappion said:
I used anti vibration padding on the bottom. Two layers.
anti vibration pad

Yea the transport box already has a pad built in on the bottom and lid. Though I've now removed from the lid as it was pretty close to the terminals.

Alloy · Jan 11, 2022

curiouscarbon said:
hi!

with the big cells, i too am building with cable instead of busbar, due to cell physically "breathing" across 0-100% charge.

100A is the highest continuous from the 280/300Ah type cell i personally will design for (to be gentle to cell limits, and also overkill BMS limit), so one or two 6awg cable in a lug is what im thinking. 6awg should be good for ~50A at least and two should be good for about ~100A. im using silicone insulated tinned copper cable, which 6awg is biggest i could find. its really soft.

anyways, good luck, im sure you can figure out something good?

Bus bars are better than wire and far far far better than putting 2 wires in lug.

Bus bars have 2 connections and a wire has 4.

DipstickDash · Jan 11, 2022

Alloy said:
Bus bars are better than wire and far far far better than putting 2 wires in lug.

Bus bars have 2 connections and a wire has 4.

Thanks for the insight. I was worried about damaging the terminal posts but I hadn't thought about the connections / resistance

DipstickDash · Jan 11, 2022

I'm pretty happy with my first build and battery box. I need to add a few finishing touches. Probably adding some more padding on the sides is one of them.

I quite like the little slot I used for the Bluetooth for BMS ?

Daddy Tanuki · Jan 13, 2022

i started with bussbars, but in reality if the top terminal post is not perfectly level in regards to the battery case then you will have the buss bars forcing the cells to twist. I bit the bullet and bought a bunch of 2 gauge wire and terminals and cut them all to the same length and crimped the fitting. it allowed the cells to not twist and put pressure on the terminals. this is in a 16S3P setup. originally it was a 3P16S setup with 6 cells locked into a bussbar which forces the cells to twist.

Alloy · Jan 13, 2022

ken morgan said:
i started with bussbars, but in reality if the top terminal post is not perfectly level in regards to the battery case then you will have the buss bars forcing the cells to twist. I bit the bullet and bought a bunch of 2 gauge wire and terminals and cut them all to the same length and crimped the fitting. it allowed the cells to not twist and put pressure on the terminals. this is in a 16S3P setup. originally it was a 3P16S setup with 6 cells locked into a bussbar which forces the cells to twist.

Bending each bus bar to fit would be faster.

Daddy Tanuki · Jan 13, 2022

Alloy said:
Bending each bus bar to fit would be faster.

I considered it but at 3mm x125mm x180mm copper bussbar is too thick for that. and since it is tying 6 terminals together you would have to bend it (possibly) in 6 different planes. was easier to just by the copper cable and crimp terminals.

Polystyrene and foam in battery case

New Member

Solar Enthusiast

New Member

Retired Engineer Tech

New Member

Retired Engineer Tech

New Member

Retired Engineer Tech

Science Penguin

Solar Enthusiast

New Member

New Member

New Member

New Member

New Member

New Member

New Member

Attachments

Solar Wizard

New Member

Solar Wizard

Similar threads