The Question; Compression or not

[Zwy]

I would not use any foam plastic between the cells as there is a question of movement as well as low ignition temperatures of the foam..

Had that discussion long ago with another member here, it's in the archives, it was about ASTM standards for flammability. I ran a test using a propane torch and some of the neoprene I installed back then, poron will be the same.

Conclusion is this, the foam is manufactured to the ASTM standard for flammability in passenger vehicles. This standard was developed to allow occupants to escape. The only way the foam burns is to apply a direct flame to it, and it won't rage into an inferno, it is quite flame resistant. The direct flame will char the surface, if you remove the flame, the foam will not burn by itself, it has to have direct heat applied and even then it is flame resistant. If you want to view the discussion and how the ASTM standard works, you will have to go look for it, it's out there somewhere, I'm posting this so you can look into it as you seem uninformed about the standard and how it applies to the foam materials many are using.

In all cases, I recommend using a material that meets the ASTM spec. Using packaging material is not using a flame resistant material. There are materials out there that meet specs for flammability and compression strength. I have posted plenty since becoming a member here in many different threads about using foam and suggest reading those. The information in those threads is a great resource.

 

[joanna_lannie]

Maybe OP can refer to this link.

Should I make LiFePO4 Battery Compression？

Currently, LiFePO4 battery compression is the more recommended practice, which can prolong battery life and enhance performance.

batteryfinds.com

 

[JanVJ]

Mind if I jump in with some questions?

I'm doing the research right now to build my first LiFe pack, I have visions of a 8s 24v 280Ah setup. My goal is to replace the 6 FLA's my cabin currently uses due to weeks on end of below freezing weather. Here's my "plan" in my noodle:

..................

I am not sure if I got any useful reply, but....

You are talking about JBD and Daly bms;
Have you looked at JK (Aka JiKong) ?
A wide selection of size´s,
Split port´s with separate control of charge and discharge
Balancing function / solution done with impressive.... current and speed
Looking at the APP I was impressed; intuitiv and visual.

The JK BMS comes in a open or a closed model.
This depend on model.
My BMS is a open model; (give more cooling in my mind)

Compression or not?
My conclusion is no compression.
This because I dont have any big load; maybe 10-20 A from a 320 Ah battery
I will have short 10-15 minutes with 150A current during warm season. (within my battery spec)
Even smaller currents during cold season.
No compression, but I will make a tight fit enclosure, and I will add a just in case extra insulation between cells.

A JK test video from Off Grid Garage, Australia

45.94US $ 29% OFF|Jk Bms 1a 2a 5a Balance Current 8s 12s 13s 14s 16s 17s 20s 24s Smart Jk Bms 60a 80a 100a 150a 200a 600a Lifepo4 Li-ion Battery - Battery Accessories & Charger Accessories - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[Zil]

Had that discussion long ago with another member here, it's in the archives, it was about ASTM standards for flammability. I ran a test using a propane torch and some of the neoprene I installed back then, poron will be the same.

Conclusion is this, the foam is manufactured to the ASTM standard for flammability in passenger vehicles. This standard was developed to allow occupants to escape. The only way the foam burns is to apply a direct flame to it, and it won't rage into an inferno, it is quite flame resistant. The direct flame will char the surface, if you remove the flame, the foam will not burn by itself, it has to have direct heat applied and even then it is flame resistant. If you want to view the discussion and how the ASTM standard works, you will have to go look for it, it's out there somewhere, I'm posting this so you can look into it as you seem uninformed about the standard and how it applies to the foam materials many are using.

In all cases, I recommend using a material that meets the ASTM spec. Using packaging material is not using a flame resistant material. There are materials out there that meet specs for flammability and compression strength. I have posted plenty since becoming a member here in many different threads about using foam and suggest reading those. The information in those threads is a great resource.

Yes. The foam you tested. Do you guaranty all the foam our members use will not melt or burn? "Oh wow That foam cost twice what This costs, I will use This. It looks just the same as That."
If the question is "compression" to limit movement, how does any lot of foam help with that?

 

[noenegdod]

Yes. The foam you tested. Do you guaranty all the foam our members use will not melt or burn? "Oh wow That foam cost twice what This costs, I will use This. It looks just the same as That."
If the question is "compression" to limit movement, how does any lot of foam help with that?

The information is what is relevant and as long as it is accurate that is all that matters. Stupid people do stupid things. It is not up to users on a forum to protect them from doing stupid things.

 

[Zwy]

Yes. The foam you tested. Do you guaranty all the foam our members use will not melt or burn? "Oh wow That foam cost twice what This costs, I will use This. It looks just the same as That."
If the question is "compression" to limit movement, how does any lot of foam help with that?

"In all cases, I recommend using a material that meets the ASTM spec."

You must have missed that part........

 

[Xepshunall]

If I were doing that project i would temporarily compress and then fiber tape them. I would use flexible busbars and build into a premade case that resembles a battery. If my project was not 8s that's what I'd have done. I'd probably consider 280ah cells as better cost per ah especially when 320ah is an overrating of a 304?ah cell. Docan should have US stock of 280's and a case that should fit 4 cells properly.

I just bought 56 314Ah cells, which I expect you would identify as 304's even though the supplier states that all cells will have actual capacities of over 320Ah, for $42.00 each plus shipping, tax, and Alibaba's 3% transaction fee.. As for value, I bought the 314's soon after buying 280's for the same price. I have another source of 314Ah for $40.00 but I think that the quality of the service is worth an extra $2.25 per cell. We'll see if I can get these suppliers to all match the cooperation of the best of them. I like your idea of compressing, taping and then removing the mechanical compression. It's like laying down to get my 32x32 jeans on when I should be wearing 34x32. With 3D printing, you'd think someone would have designed boxes that have a fluted top so we could place our cells upside down on the plexiglass table cover and slide the box onto the cells before putting silicone sealant into the groove of the box before sliding the tongue of the lid into it and screwing it down. Oops. I forgot the BMS. This is gonna be messy.

 

[pshoe]

With 3D printing, you'd think someone would have designed boxes that have a fluted top so we could place our cells upside down on the plexiglass table cover and slide the box onto the cells before putting silicone sealant into the groove of the box before sliding the tongue of the lid into it and screwing it down. Oops. I forgot the BMS. This is gonna be messy.

Could not tell if you were joking so the joke may be on me. Those Eel DIY battery boxes are nice. The end comes off and the cells can be compressed (if that's your thing). They have 4s and 8s.

 

[TenagaSurya]

I just bought 56 314Ah cells, which I expect you would identify as 304's even though the supplier states that all cells will have actual capacities of over 320Ah, for $42.00 each plus shipping, tax, and Alibaba's 3% transaction fee.. As for value, I bought the 314's soon after buying 280's for the same price. I have another source of 314Ah for $40.00 but I think that the quality of the service is worth an extra $2.25 per cell.

Hi, I take it those cells haven't arrived yet? But do you mind sharing (either here or as PM) the Alibaba supplier you chose?

 

[Xepshunall]

Grade A 3.2v 230ah Lf280k 304ah 320ah Lifepo4 Lithium Ion Batteries 6000 Cycles Lfp Diy For 10kw Energy Storage Station Lf280k - Buy Grade A Lifepo4 300ah 302ah 304ah 320ah Catl Lifepo Batteries Eve Lf280k 14.34 Kwh 48v Lifepo4 Batterie Grade A For S

Grade A 3.2v 230ah Lf280k 304ah 320ah Lifepo4 Lithium Ion Batteries 6000 Cycles Lfp Diy For 10kw Energy Storage Station Lf280k - Buy Grade A Lifepo4 300ah 302ah 304ah 320ah Catl Lifepo Batteries Eve Lf280k 14.34 Kwh 48v Lifepo4 Batterie Grade A For Solar Packs 8000 Cycle 3.2v 280ah 560ah Diy...

www.alibaba.com

I bought 32 of these shipped DDP by sea for $40 each and 560 shipping. They were delivered by FedEx

10000 Cycle Hithium 280ah 314ah Prismatic Solar Lithium Ion Batteries Cell 3.2v 280ah Lifepo4 Battery Energy Storage Battery - Buy Lifepo4 Battery 280ah Battery lifepo4 Cell 3.2v Lifepo4 Battery Cells lithium Ion Batteries solar Battery lithium Batte

10000 Cycle Hithium 280ah 314ah Prismatic Solar Lithium Ion Batteries Cell 3.2v 280ah Lifepo4 Battery Energy Storage Battery - Buy Lifepo4 Battery 280ah Battery lifepo4 Cell 3.2v Lifepo4 Battery Cells lithium Ion Batteries solar Battery lithium Battery lithium Lifepo4 Cell home Energy Storage...

www.alibaba.com

I bought 24 of these shipped DDP by sea for $42 each and $471 shipping. They were delivered by UPS

If you get a shipping rate that is more than $20 per cell, tell them you want them 3 to a box so the shipping rate will be lower. I ran into this with the first supplier that I listed.

TDT BMS up to 180A continuous are readily available on Aliexpress.

https://www.aliexpress.com/item/3256806504857588.html?spm=a2g0o.order_detail.order_detail_item.3.3716f19c5wKigM

I have 3 of the 180A 16s ones coming for $80.44 each. These are for having my 3 packs on my 48-volt home system when I'm not driving my 144-volt truck. I'll carry the packs with each BMS disconnected while the truck batteries are series connected. I haven't found a better way to use my truck as part of my home system, including DC charging, while being able to operate at 144 volts nominal. If anyone is doing something similar but better implemented, I'd love to learn about it.

 

[Xepshunall]

This is the first BMS and some of the $40 cells. These came in yesterday so I still have to connect them. For now, I'll just pinch the balance leads between layers of bus bar finger tight with a nut driver. I am very picky about ring terminals so I'm intent on finding good ones at a fair price before I commit. This is not a request for links. I prefer to search the internet for options. I'm going to use them in a vehicle so they have to be exactly what I believe are right for the job. This set is just the first that I'm charging and balancing before the 3 16s BMSs arrive. You can't tell by the avatar but I'm very excited about this endeavor. I took pictures of all my boxes of batteries but then I thought about the rules of personal information. I have 56 cells at 314Ah and 16 at 280Ah. The 280s will be 12V for powering lights and mini PCs. Eight of the 314s will be 24V for an off-grid solar inverter to run my 110A/C 5 cu ft chest freezer and 4.6 cu ft fridge. The remaining 48 314s will be used with 48-volt, 6.2kW off-grid solar inverters that will charge the cells for the truck and run my ductless mini split. I live in a converted 10x12 shed and have a 7x9 concrete building for food storage. Life just became amazing.

 

[TenagaSurya]

You can't tell by the avatar but I'm very excited about this endeavor.

Hehehe! Thanks for putting all that down, I appreciate it.. I like the idea of combining vehicle & home storage, good luck with that!

 

[AntronX]

I haven't found a better way to use my truck as part of my home system, including DC charging, while being able to operate at 144 volts nominal. If anyone is doing something similar but better implemented, I'd love to learn about it.

Id like to see this truck setup.

 

[Xepshunall]

Could not tell if you were joking so the joke may be on me. Those Eel DIY battery boxes are nice. The end comes off and the cells can be compressed (if that's your thing). They have 4s and 8s.

No. I wasn't joking. If I do decide to invest in a 3D printer, I might design a box to demonstrate what I believe to be a good means to gather the cells into it without having ever applied compression. I think it should be impossible for the box to short a cell or group. Any impractical components that raise the price in the name of convenience are probably not convenient enough to justify the added expense. This includes balancing PCBs. People are lazy enough without promoting mental laziness.

 

[Ohms_Cousin]

Id like to see this truck setup.

me too!!

 

[Daddy Tanuki]

As a DIY´er with too much spare time on my hand;
I am bulding a 12 VDC 320 Ah LiFePo4 based on 4 pcs 3,2 volt cells.

And the reason why would be to save some money.
My wild guess is that the cost will be aprox 1/3 of the price for a 300Ah ready made battery.

How ever; I would like a battery that looks "clean".
I dont want a battery with a look like a piece of something you find at the dumpster.

I am just out from this morning management project meeting about compression or not.
(Management consist of 1 person; ME...)
At this moment the vote went for NO compression.

- I believe compression would be kind of "finetuning". I dont have the tools to do that kind of accurate adjustments.
- Dont think my ready made of the shelf 12V 200 AH battery (bought for big bucks from a local store) got any compression (have not looked inside)
- Add lifetime? The seller claim 6000 cycle. That would be 16 years. In 16 years (2038) I probably got new hobbies.
- A set up with compression would add a lot of extra bits and pieces and most DIY solutions appear like a sputnik satellite.

Until I do get the "aureka" moment I will continue without compression.

What would you do?
And why?

The sun is back for the season.

OK without going into all the fine details. compress to about 12 PSi. use aluminum plates/rods and springs: why you can use them as heat spreaders (or cooling with peltier devices) if your climate requires this. you get a moderate level of compression but the aluminum plates also double a a heat sink to cool or heat as needed. just my thoughts.

 

[newbostonconst]

I have yet to see a cell that wanted to expand be stopped from expanding....Best to keep the voltage target of 3.5 volts and they wont expand...