New battery build (16S4P)

[Steve_S]

@Steve_S Thanks for your message! No worry I did plan to wrap those bus bars (they are not permanently fixed right now) and when I did shrink wrap the crimped terminals so far, I did what you posted in the picture.

The real devil with out systems is the darn wee little details that can end up creating huge issues. PITA to ensure every i is dotted & T is crossed but one has to do it.

 

[extrafu]

@Steve_S I fully and I really appreciate your advices! I'm in no rush to put the new battery pack in service - I'm slowly building it and trying my best to avoid any mistakes!

 

[extrafu]

I made some nice progress this past weekend on the build. I still need to:

1. wrap the busbars (nothing is permanently fixed right now)
2. calculate and apply proper compression on the plates through the 6 bolts
3. shorten the wires and properly connect all BMS cell balancing wires
4. interconnect the four JK BMS
5. perform an initial charge of each pack (individually)

I have a couple of questions:

1. is normal Ethernet cable wiring being used here by JK to interconnect the BMS? The provided ones, if used for that, are way too short
2. to charge each pack, I was considering using my DC power supply (I got that model https://www.amazon.ca/gp/product/B0CQKYMG61). Set it to 54.8V and let it charge for many hours. Sounds good? Right now all cells are exactly at 3.20V.

Thanks!

 

[doctron]

Nice work.
Post more photos of the battery pack.

What enclosure are you using for bms and other parts?

 

[extrafu]

@doctron A friend 3D printed brackets for the BMS and the front panels. Here are they are:

• https://www.printables.com/model/795312-jk-inverter-bms-anschluss-standfuss
• https://www.thingiverse.com/thing:6469916

Thanks!

 

[Shawn Hayes]

I made some nice progress this past weekend on the build. I still need to:

1. wrap the busbars (nothing is permanently fixed right now

Very nice progress! Looks like our setups are similar. On my aluminum compression plates, I use a bicycle torque wrench, and use the lowest allowed setting to tighten them at roughly 70% SOC. Basically slightly hand tight with a standard wrench.
May have been answered, but it’s my understanding that a class T fuse, needs to be placed in front of the most positive battery terminal.
Maybe too late to change, but a safer/alternative way to parallel your four packs instead of copper bus bars. Using welding cables that go to a Blue Sea 1000 amp bus bar like mine pictured below. Makes it easier to expand if you decide to in the future. I just recently added to more packs to make a 16s6p now, just added more cables to the bus bar with a cover.
(Note: pictures are taken before I added the two new packs)

https://www.bluesea.com/products/category/18/111/BusBars/PowerBar_1000

 

[Brucey]

Very nice progress! Looks like our setups are similar. On my aluminum compression plates, I use a bicycle torque wrench, and use the lowest allowed setting to tighten them at roughly 70% SOC. Basically slightly hand tight with a standard wrench.
May have been answered, but it’s my understanding that a class T fuse, needs to be placed in front of the most positive battery terminal.
Maybe too late to change, but a safer/alternative way to parallel your four packs instead of copper bus bars. Using welding cables that go to a Blue Sea 1000 amp bus bar like mine pictured below. Makes it easier to expand if you decide to in the future. I just recently added to more packs to make a 16s6p now, just added more cables to the bus bar with a cover.
(Note: pictures are taken before I added the two new packs)

https://www.bluesea.com/products/category/18/111/BusBars/PowerBar_1000

Love the way you've mounted those mnedc175s, is that a custom bracket and then the midnite breaker protectors?

 

[Shawn Hayes]

Love the way you've mounted those mnedc175s, is that a custom bracket and then the midnite breaker protectors?

Thank you. Yes, I used 2” wide aluminum bar from Lowe’s. Used my bench vice to put the necessary bends to give mounting points to the cabinet floor/back wall to make it stable.
Then painted the bars flat black and added the breaker protectors.
Decided to add those after the fact to give an easy on/off switch as well as added protection even though I have class T fuses as well.

 

[robbob2112]

Very nice progress! Looks like our setups are similar. On my aluminum compression plates, I use a bicycle torque wrench, and use the lowest allowed setting to tighten them at roughly 70% SOC. Basically slightly hand tight with a standard wrench.
May have been answered, but it’s my understanding that a class T fuse, needs to be placed in front of the most positive battery terminal.
Maybe too late to change, but a safer/alternative way to parallel your four packs instead of copper bus bars. Using welding cables that go to a Blue Sea 1000 amp bus bar like mine pictured below. Makes it easier to expand if you decide to in the future. I just recently added to more packs to make a 16s6p now, just added more cables to the bus bar with a cover.
(Note: pictures are taken before I added the two new packs)

https://www.bluesea.com/products/category/18/111/BusBars/PowerBar_1000

I love the rack and battery compression method. Enclosed with steel front and back and a passive vent to the outside would add to it if you haven't already done that....passive meaning a fair sized pipe to the outside with the end covered in foil zip-tied over the outside so at a reasonable PSI it blows out.

What kind of rack is that?

 

[Shawn Hayes]

I love the rack and battery compression method. Enclosed with steel front and back and a passive vent to the outside would add to it if you haven't already done that....passive meaning a fair sized pipe to the outside with the end covered in foil zip-tied over the outside so at a reasonable PSI it blows out.

What kind of rack is that?

I do have the cabinets vented but not to the outside as it a climate controlled mech room.
It’s a Gladiator garage cabinet from Lowe’s. I built my own rack inside to support the batteries.
Hindsight being what it is, I wish I’d planned for expansion differently. I recently expanded to 6 packs. So I bought another cabinet, cut it in half, and added the two new packs on the other side of the laptop shelf. I’ll add and update photo below….
But I like being able to close the cabinet doors and not see the setup. Also, being enclosed, if you don’t know what’s inside, you might not even suspect they hold batteries.

 

[robbob2112]

I do have the cabinets vented but not to the outside as it a climate controlled mech room.
It’s a Gladiator garage cabinet from Lowe’s. I built my own rack inside to support the batteries.
Hindsight being what it is, I wish I’d planned for expansion differently. I recently expanded to 6 packs. So I bought another cabinet, cut it in half, and added the two new packs on the other side of the laptop shelf. I’ll add and update photo below….
But I like being able to close the cabinet doors and not see the setup. Also, being enclosed, if you don’t know what’s inside, you might not even suspect they hold batteries.

The vent to the outside would be in case a cell vented while the doors are closed, it would pop the foil cover for over-pressure, but not do air exchange with the outside otherwise. This would allow hydrogen to disipate harmlessly outside in the event of a vent.

 

[extrafu]

@Shawn Hayes Thanks for your comments - and you have a superb build sir! My class-T fuses are connected on each positive battery terminal - that is, the positive terminal of a 16S pack. Regarding tightening the bolts for the aluminium compression plates, I am still a bit unsure. EVE recommends 300 kgf or 660 lbf. I have two rows of 8 cells side by side, so I guess it would be 1320 lbf. Using 6 x 3/8 bolts it means 220 axial lbs/bolt. Using https://www.engineersedge.com/calculators/torque_calc.htm it looks like I'll have to apply 17 in-lbs (or 2 Nm) on each nuts - so almost hand tight like you said. @Dynoman described this in his post: https://diysolarforum.com/threads/r...for-eve-cells-lf280k-lf304.78285/post-1095499

 

[extrafu]

Build has progressed well again today. Wrapped the busbars, connected all balancing wires, tested all four BMS, etc. All good. I need to connect the temperature sensors (4 per pack). Do you guys have any suggestions on where to place them and how to attach them?

 

[740GLE]

I gently snuck them on the edge of the cells where they touch, maybe 1” down with the cell separator/insulators I didn’t have to shove it down.

I’m more worried about low temp charging cut off and I’d much rather know internal cell pack temp is above 35f to allow charging.

 

[extrafu]

@740GLE Thanks for your answer. For me, there's no room between cells so I can't snuck them there. Maybe just tape them on side of cells 2/6/10/14?

 

[740GLE]

I’d call that good enough

 

[doctron]

You may connect one lead to bus bar between cells 8 and 9.
Other 2 can be connected to cells surfaces

 

[extrafu]

Today while torquing all bolts I've noticed that one weld on one of the 64 cells is a bit badly made. See attached picture. I have 2 spare cells. Should I swap it or leave it there and call it a day? I will likely put the whole pack in service tomorrow. Thanks!

 

[Brucey]

Today while torquing all bolts I've noticed that one weld on one of the 64 cells is a bit badly made. See attached picture. I have 2 spare cells. Should I swap it or leave it there and call it a day? I will likely put the whole pack in service tomorrow. Thanks!

These are MB30 from Gobel? I would swap it with a spare as you have them on hand.

 

[extrafu]

@Brucey Yep, correct for the cells. Thanks for your comment, I'll swap it tomorrow! I wish I had noticed it sooner

 

[extrafu]

New battery pack is live! Still lots of cleanup to do (remove FLA batteries, position the temperature sensors, etc.). I'm very happy!

 

[740GLE]

Today while torquing all bolts I've noticed that one weld on one of the 64 cells is a bit badly made. See attached picture. I have 2 spare cells. Should I swap it or leave it there and call it a day? I will likely put the whole pack in service tomorrow. Thanks!

Let me squint some more and I might be able to tell with such a blurry picture.

 

[extrafu]

More cleanup done today... it's starting to look like something nice!

 

[garrisonhouse]

Beautifully done. Now that you're done with the build, do you think that you need all of the space these shelves give you, or would you be able to go a little smaller?

 

[robbob2112]

Nice battery racks - and nice job from what I can see

I like the wall of Schneider - mine is on the way - did you install it yourself?