AJW22's modular 3d printed 60kWh PowerShelf

[ajw22]

Small update:
Added TP-Link HS 105 Smart Wifi Plugs to the inverters, so that the Raspberry Pi can disconnect the inverters during off-peak hours when the batteries are kinda low.

[Cover1987]

Hi AJW,

im a big fan of your 3d printed packs. In fact I have only an anycubic i3 Mega (200x200mm base) so i decided to use your designe and make it possible to print at my printer in 2 parts. I made it a littlebit bigger (136 cells)   and i'll use 2 busbars and connet only 1 cell with one fuse wire.

If someone wants my parts i can also upload step files of my version.

Some testing
 

Does it fit together?



A draft of to complete assembly
 

And now the first part is printing

[ajw22]

im a big fan of your 3d printed packs. In fact I have only an anycubic i3 Mega (200x200mm base) so i decided to use your designe and make it possible to print at my printer in 2 parts. I made it a littlebit bigger (136 cells)   and i'll use 2 busbars and connet only 1 cell with one fuse wire.

Thanks.  Never thought of connecting parts like that.  Are you planning to glue them together?

Best to fully build and test one pack before mass producing all the parts.  Some potential issues I see:
* structural stability of joining the 2 parts, particularly with the weight of all 136 cells
* properly fix the 2 busbars (one loop?) onto the pack.  In my current design, I added anchoring holes because the busbar would move enough to rip out the fuses.

Is there a particular reason why you left space in the middle of the pack (where my one busbar would be)?

[Cover1987]

Hi!

Im planing to glue the 2 parts together. But after the first test print the joining seems very stiff and tough. Maybe it will stay in place even without glue.
But the first complete pack will be glued. I made some good experience with some glue in an other project. And for sure, i'll test the pack first before i start printing kilos of PLA

I see you had a deep look at my design
I made the middel rip becaus of mirror geometry. so i can use one part for both sides.
It also has the positiv effect that i can use the gap to ziptie the busbar (im not sure if i'll make a loop bar). Maybe thats also a great spot to place a temp sensor.

[BobinTN]

ajw22;
You are my new powerwall hero. Just found and read about your build.

I have a 24V system with about 8kW of storage.  I have been monitoring electrical usage of my home using InfluxDB/Grafana for awhile now.

I am currently running 3 chinese BMSs using bluetooth.

I have been trying for awhile to use my Raspberry Pi 3 to to collect data off of the BMSs without success.

It sounds like you have achieved this.

Am I out-of-line requesting a copy of your Python Code in which you are doing this.

Thanks for any support.

BobinTN

[ajw22]

ajw22;
You are my new powerwall hero. Just found and read about your build.

I have a 24V system with about 8kW of storage.  I have been monitoring electrical usage of my home using InfluxDB/Grafana for awhile now.

I am currently running 3 chinese BMSs using bluetooth.

I have been trying for awhile to use my Raspberry Pi 3 to to collect data off of the BMSs without success.

It sounds like you have achieved this.

Am I out-of-line requesting a copy of your Python Code in which you are doing this.

Thanks for any support.

BobinTN

Thank you for the compliments.  I've attached my Python code, but I should warn you.  While I am a seasoned programmer, before this project I've not done any work with sensor data logging, Grafana, Bluetooth, Raspberry Pi, or even Python.  It's definitely a mess that's on my Need-To-Rewrite list, but it's been working well enough for my needs for now.

Some notes:
Hardcoded for 14S BMS.  Probably works fine on 7S, with top 7 values always being 0.
It samples data for about 5 minutes, then writes the sum/average to a local Postgresql database.  5 min was chosen to reduce the number of writes and thus extend the SD card life.
Some math is convoluted, because I was testing if Postgresql would run better with just integer math using millivolts.
There is superfluous Bluetooth signaling, resetting, etc, because I was having stability issues with the onboard Bluetooth module.  I've disabled it, and use a USB Bluetooth dongle now - much more stable.


Python3, uses bluepy library

Code:

$ sudo apt-get install python3-pip libglib2.0-dev
$ sudo pip3 install bluepy

Looking forward to seeing pictures of your project!

[Korishan]

Thank you for the compliments.  I've attached my Python code, but I should warn you.  While I am a seasoned programmer, before this project I've not done any work with sensor data logging, Grafana, Bluetooth, Raspberry Pi, or even Python.  It's definitely a mess that's on my Need-To-Rewrite list, but it's been working well enough for my needs for now.

You might wanna double check your attachments    Dragging files into the box is only for images. you have to select the Attachments Browser button to add attachments.

I agree with the coding aspect, as well. One thing is I learned coding in Windows. And setting things up in other platforms and configuring linux to accept the data is still a bit vague for me. I always have to resort to some kind cheat sheet 

[ajw22]

You might wanna double check your attachments    Dragging files into the box is only for images. you have to select the Attachments Browser button to add attachments.

Fixed.  I selected the attachment file, but didn't click on the "Add Attachment" button.  Damn wide monitor

[BobinTN]

ajw22;
I got it.

A quick look, I think I can handle this. Thank you so much for sharing. I will get some pictures of my setup. But compared to a lot of you guys, I am a hack. I love your battery pack setup. I am not into 3D printing, but your, what I call, battery pack bus with the x60 connectors, is beautiful.
I will get some pictures and explanations up here tomorrow. I will also let you know how me disecting your code goes.

Thanks again.

Bob

[ajw22]

Small update:

Winter is slowly coming to an end, days are getting noticeably longer, and solar PV generation is starting to look good again.  Time to get working on my Powerwall!

Installed the 2nd shelf, on the left side wall with enough space for 6 more batteries.  Securely anchored to the floor and wall.

Installed battery#5 (10kWh) on said shelf.  I've randomly selected the cells, and so the pack capacities are not all quite the same.  Will need a few charge/discharge cycles to get an idea of which ones have too much/little capacity, and swap cells accordingly.



Todo:
Now that almost all the major components are there, install the last cable ducts to hide the cable spaghetti.
Start testing cells for Battery#6.
Install the last 3.2kW of solar panels to get the 3rd and last charge controller working.
Install 4th and last GTI.