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w0ss semi DIY powerwall V2
#11
Thanks. So the work you are doing with the custom boards, is that just so you can interface with the on-board LG BMS? Is there a benefit of using that VS just bypassing and using a separate BMS as you recommended?
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#12
The board I made is really just a breakout board of the cells and whatever else is connected. I wasn't able to talk to the existing "BMS" I use that in quotes since it has no disconnect so it looks like it is really a monitoring board with minimal balance resistors. my board just replaces it so I can use an external BMS.
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#13
w0ss would you mind walking me thru how to connect this to a Daly BMS? Thanks
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#14
(04-08-2020, 02:01 PM)themiz Wrote: w0ss would you mind walking me thru how to connect this to a Daly BMS?  Thanks
You have a few options.

1. You can purchase the connection that the board has and then solder the Daly leads directly to it. Allied had the lowest cost when I looked for the connector. I did this for my first test. I then covered it all in hot glue to act as something of an insulator.

2. Another option would be to design a breakout board. I did that option and would be happy to share my design if you wanted to use it.

I have the pinout of the connector somewhere let me post that.

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#15
Interesting.  Yes I actually purchased that connector.   These are 14s batteries, correct?   I was thrown off by the fact there are 24 pins.      

I'd be curious to see your board design, I though I have no idea how to get one made.  Is there a place to send a design that will manufacture it?
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#16
Here is a link to the board I designed. https://easyeda.com/william.carlson/bmsv2 I used JLCPCB which I think is the same company as EasyEDA. They will make the board and do the surface mount components(fuses).

The 24 pins are a bit confusing. It looks like the built in "BMS" board is setup as 2x7s monitoring boards. so 16 of the pins are voltage sense leads(2x8 for the 2x7s). I assume others in there are used for temperature sensors but I never really investigated.

EDIT:
One thing to mention is my board the holes don't align 100% to the stock mounting points. But they still mostly fit and I could screw down to secure the board.
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#17
Thank you for sharing your work with us.  I just ordered 8 of these packs for my house.  Regarding the board, is it just simple as uploading to the JLCPCB site, choose number of boards I want and that's it?  Do the connectors come with the board when ordered or do I have to order the connectors and solder them in separately?  Sorry for the newbie questions, never ordered PCB boards before.  Besides the Batrium, would you recommend anything else for 8 batteries? Would it be better to go with 1 Watchmon 5 and parallel all those cells in parallel like you did, or add 7 of the Multimon (making it very costly).  Another thought that I have is to do 8 separate active BMS.  Any suggestions.  Thank you.
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#18
(04-21-2020, 05:28 AM)Etn06448 Wrote: Thank you for sharing your work with us.  I just ordered 8 of these packs for my house.  Regarding the board, is it just simple as uploading to the JLCPCB site, choose number of boards I want and that's it?  Do the connectors come with the board when ordered or do I have to order the connectors and solder them in separately?  Sorry for the newbie questions, never ordered PCB boards before.  Besides the Batrium, would you recommend anything else for 8 batteries? Would it be better to go with 1 Watchmon 5 and parallel all those cells in parallel like you did, or add 7 of the Multimon (making it very costly).  Another thought that I have is to do 8 separate active BMS.  Any suggestions.  Thank you.
You would upload the board to JLCPCB and they will make it, I also had them do the SMT assembly as well. If you choose that option then all you would have to do is order and solder on the connection that goes to the battery pack and the connector to your BMS. They are all thru hole and pretty easy.

For 8 batteries that is a tough one. My personal thought is put them in parallel with a watchmon4 and cellmons's. You get more balancing with the cellmons and if you have 8 189ah cells in parallel you might need more balancing than a watchmon5 can do. For two I haven't noticed any issues with the watchmon5. Maybe as a compromise you put 2 or 4 in parallel and get a few multimon's.
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#19
Looks like the part DB128H-5.08-12P-GN-S has been discontinued.  Is there anything else that would fit your board?  I think I have it almost figured out on JLCPCB website to make the order.  Just making sure that the size of the board is 200mm x 65mm.  Otherwise all the other options are default and add SMT at the top of the board.
Thanks for your help preparing to get this fun project on the way.
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#20
the spacing for that part is standard. I bought them off Amazon.
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