Space saving cell compression design for RV EVE 280 12v 2P4S build

[Reccer]

I am converting my motorhome coach from using FLA batteries to LiFePo4 and wanted to share my final design/build. I've read hundreds of posts on the need for and reasons to compress the cells and have come down on the side of providing light compression.

My 560Ah EVE LF280K 2P4S battery bank will be mounted in an outside storage compartment by my two 40A solar controller/chargers and within six feet of a 75A converter/charger and the original FLA distribution panel.

I was looking for a design that minimized the footprint of the bank as it will be displacing much-needed storage space for all my RVing crap. All the designs I've seen use a threaded-rod compression design but I wanted eliminate the rods as they added extra width to the sides of the bank.

I came up with a box design that uses a pressure plate instead of rods. The pressure plate is pushed against the cells using five set screws and t-nuts mounted into the fixed board (BMS is mounted on this board). The set screws hit metal washers on pressure plate to keep from digging into the wood. Just like a rod design, the set screw/pressure plate design can be adjusted to provide whatever compression you want.

There are silicon sheets between the cells (and at each end), mainly to help with cell movement in this mobile application. I've also placed 1/8" foam underneath and along the sides of the cells to help with shock absorption. These might not help but they make me feel better.

Hopefully this alternate design will give fellow DIYers an idea or two.

 

[sunshine_eggo]

Nice looking install.

I requested a move to "Show and Tell" section.

155A total charge potential - no worries for the cells, but BMS?

 

[Reccer]

No problem to move thread - should be put where it reaches the right audience.

I'm using a 200A JBD BMS.

 

[jwelter99]

I am converting my motorhome coach from using FLA batteries to LiFePo4 and wanted to share my final design/build. I've read hundreds of posts on the need for and reasons to compress the cells and have come down on the side of providing light compression.

My 560Ah EVE LF280K 2P4S battery bank will be mounted in an outside storage compartment by my two 40A solar controller/chargers and within six feet of a 75A converter/charger and the original FLA distribution panel.

I was looking for a design that minimized the footprint of the bank as it will be displacing much-needed storage space for all my RVing crap. All the designs I've seen use a threaded-rod compression design but I wanted eliminate the rods as they added extra width to the sides of the bank.

I came up with a box design that uses a pressure plate instead of rods. The pressure plate is pushed against the cells using five set screws and t-nuts mounted into the fixed board (BMS is mounted on this board). The set screws hit metal washers on pressure plate to keep from digging into the wood. Just like a rod design, the set screw/pressure plate design can be adjusted to provide whatever compression you want.

There are silicon sheets between the cells (and at each end), mainly to help with cell movement in this mobile application. I've also placed 1/8" foam underneath and along the sides of the cells to help with shock absorption. These might not help but they make me feel better.

Hopefully this alternate design will give fellow DIYers an idea or two.

Nice, where did you source those bus bars?

 

[rhino]

Nice, where did you source those bus bars?

 

[Reccer]

I really like these bus bars. They were purchased on Ali-Express from Li-ion Battery Manufacturer Store. Here's a link to the 300A parallel bars https://www.aliexpress.com/item/325...store_pc_home.productList_2002588993900.pic_3

Had free shipping and took around 30 days from order to receipt.

 

[jwelter99]

I really like these bus bars. They were purchased on Ali-Express from Li-ion Battery Manufacturer Store. Here's a link to the 300A parallel bars https://www.aliexpress.com/item/3256802884117913.html?pdp_npi=2@dis!USD!US $8.90!US $8.90!US $8.90!!!!@2101e9d216530621807107981e87b5!!sh&spm=a2g0o.store_pc_home.productList_2002588993900.pic_3

Had free shipping and took around 30 days from order to receipt.

I was afraid this is what they were. I've used these and they are nowhere near capable of the advertised current. They are not pure copper but some kind of "red metal" and will start to have issues >100A and be glowing orange by 300A.

There is another vendor of similar looking bus bars out of the EU somewhere where they are very good quality but have been hard to source in small volumes. I was hoping you had a solution for that......

 

[Reccer]

I was afraid this is what they were. I've used these and they are nowhere near capable of the advertised current. They are not pure copper but some kind of "red metal" and will start to have issues >100A and be glowing orange by 300A.

There is another vendor of similar looking bus bars out of the EU somewhere where they are very good quality but have been hard to source in small volumes. I was hoping you had a solution for that......

Thanks for the info. They have been working fine in my application but I don't pull heavy currents; and my build has 200A BMS so they won't get over that. I'll keep an eye on them for issues.