EVE LF280K Build pics - DIY Woodworker version

[mwk1000]

This is a balance of easy ( for me ) to make and the MANY smart folks discussing. I chose Poron 1/4 foam separators in a oak box with neoprene side / bottom cushions the "front" is easy to disassemble for upgrades ( bms , cells maybe ) the case compresses the foam by 25%, the bus bars (72mm flex ) needed a very slight maybe 1 mm hone to fit. I will add the remaining cover with a 140mm temp activated Nashua PC fan ( 12 volt 3 pin ) about 30$ for fan/temp controller and 5amp 48->12 converter if the temps are an issue but my basement is a steady 65 all year so probably no need the holes and gaps in foam should provide airflow. The length was set and the bottom spacing is set to 25% compression ( 0.56 " ). Still some cleanup and tuning the BMS but it's alive and ready for it's first charge. !! Used oak and extra bracing and some crazy strong and flexible polyurethane adhesive instead of steel rods ( I'll add them if needed but I don't expect to ).

 

[MaximusAnonus]

Very nice. I'm about to embark on a similar journey with the same cells (but 48pcs of them).
I have a big CNC router at my disposal so I was thinking about some 24mm (1") plywood shelf attached on one side to the main wall (batteries will be stored in a detached cellar near my house) and then some thin (3mm?) plywood as cover with some big low rpm fans to get a bit of airflow on the batteries.
I'm still unsure if I will compress the cells or if I will use flexible bus bars. I don't believe there is much of a point in compressing the batteries if there are flexibe bus bars protecting the studs from being under pressure from the slight battery movement during cycling.
Thoughts? Anyone running a similar setup?

 

[Bluemalibu]

I'm still unsure if I will compress the cells or if I will use flexible bus bars.

Thoughts? Anyone running a similar setup?

I am opting for both... compression, and the flexible connectors on my 32 LF280K cells. 1/32" poly insulating panels are sandwiched between each. I'm assembling the second tier of cells today. (Misguided energy policies here in the Great State of Confusion have us experiencing black-outs on the grid... thus my assembly of the combined 91 kWh battery bank.)

 

[mwk1000]

I was thinking the foam would compress on each side as the charge grew so "maybe" the center to center would be fine . But I was willing to go for safer since I don't really want to do this again anytime soon --- And I am also filling up box #2 this weekend for 560AH total into a sol-ark 15K that nicely has 2x200 amp breakers. BTW I used the same lifepower battery in my RV ( 24v 200ah ) + victron 24-12v 70 amp love it. All led 1w lights ...
-- Now I have to clean up my BMS wires !!! Very nice looking...

 

[mwk1000]

I was thinking the foam would compress on each side as the charge grew so "maybe" the center to center would be fine . But I was willing to go for safer since I don't really want to do this again anytime soon --- And I am also filling up box #2 this weekend for 560AH total into a sol-ark 15K that nicely has 2x200 amp breakers. BTW I used the same lifepower battery in my RV ( 24v 200ah ) + victron 48-12v 70 amp love it. All led 1w lights ...
-- Now I have to clean up my BMS wires !!! Very nice looking...

My gut says you don't really get to your 6K cycles without compression reading between the lines as it were. So 0.25c 15-95% SOC usable I am hoping to exceed 6k until the next new thing at 1/10/$$ comes along

 

[rhino]

I was thinking the foam would compress on each side as the charge grew so "maybe" the center to center would be fine . But I was willing to go for safer since I don't really want to do this again anytime soon --- And I am also filling up box #2 this weekend for 560AH total into a sol-ark 15K that nicely has 2x200 amp breakers. BTW I used the same lifepower battery in my RV ( 24v 200ah ) + victron 48-12v 70 amp love it. All led 1w lights ...
-- Now I have to clean up my BMS wires !!! Very nice looking...

Just FYI, "regular" foam loses its ability to bounce back so eventually when at low state of charge they might not have a lot of compression on them. That is what https://www.mcmaster.com/86375K64/ is for. I don't know how much difference it actually makes but that is why"Poron urethane" is used when something is expanding and contracting a lot.

 

[Bluemalibu]

And I am also filling up box #2 this weekend for 560AH total into a sol-ark 15K that nicely has 2x200 amp breakers. BTW I used the same lifepower battery in my RV

Ahhh... great minds think alike, my friend!

 

[Bluemalibu]

My gut says you don't really get to your 6K cycles without compression reading between the lines as it were. So 0.25c 15-95% SOC usable I am hoping to exceed 6k until the next new thing at 1/10/$$ comes along

My thoughts, exactly. And I figured even a bit more conservative, to try and baby these cells into a long and happy life. I doubled the needed bank capacity in order to keep them within a 30-80% operating window. But even treating them with kid gloves, I realize that nothing is guaranteed in this life, so I bought two extra cells while they are available, in order to keep a couple reserve on hand.

 

[mwk1000]

Just FYI, "regular" foam loses its ability to bounce back so eventually when at low state of charge they might not have a lot of compression on them. That is what https://www.mcmaster.com/86375K64/ is for. I don't know how much difference it actually makes but that is why"Poron urethane" is used when something is expanding and contracting a lot.

Understood - that is Poron foam I used.