w0ss semi DIY powerwall V2

vegburner

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Mar 24, 2020
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10
to add to the confusion, i DO NOT have voltage through my case...@wOss did both of your cases show voltage?
 

HydroGeo

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May 7, 2020
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So far, I have only checked one of my three modules after seeing that post a few pages back. I did not have continuity between the negative terminal and the case suggesting to me that the case was not bonded to the negative. I still need to open the modules again and inspect them in more detail. When I do, I'll take some photos.

I received my boards the other day as well as all the parts. I started soldering them, but have yet to finish. I definitely appreciate the board and design, thanks again w0ss. Once I have the boards completed and installed, I'm looking forward to checking the cell voltages to make sure everything looks okay. Also received my Watchmon and MM8's. It was pricey, but I think it will be worth the cost.


vegburner said:
@hydro
Would this be an option at the battery? https://www.delcity.net/store/Del-City-Manual-Reset-(Switchable),-Surface-Mount/p_811053.h_195738 ----Your terminal fuses look nice and clean.


I considered a circuit breaker, but seems like a lot of folks go with fuses. No sure if there is a reason for that, I haven't looked intothe breaker specs. The costs come out to be about thesame from what I can tell.

Like many other folks,I will be using a shunt-trip breaker as my overallbattery disconnect, but am also placing a main fuse in that line as well. I guess breakers could work on each of the module strings, but like I said...based on what I've seen, fuses seem to be the common method for protection.

I agree, these terminal fuses are nice and clean. I measured the terminals on the modules and I believe these terminal fuses will fit. the holes on the terminal fuses are plenty big compared to the terminal posts on the modules. The width of the terminal fuse (about ~3/4"seems to fit through the opening on the module (~1") such that the terminal cover can be closed and no modification should be needed. I have seen references to these fuses being used on lithium batteries, but have not reliably confirmed that yet.
 

Sojourner

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May 7, 2020
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15
A few things...

I did NOT have continuity between the case and the terminals. I only bought one cell. Regretting that now that it seems these units turned out to be pretty good. Paid all that shipping cost for one item...d'oh

When I hooked up a wire harness for BattGo BG-8S (max 8 cell) monitoring, for the first set of 7S (cells 1-7) the black wire went to Pin 2 (Cell1 neg) of the LG connector. Straightforward enough. But for the second set of 7S (cells 8-14), the black wire went to Pin8 (Cell8 neg) to get proper readings for the latter half of the cells. Kind of confusing, until I recalled what w0ss mentioned earlier about the original monitoring board being split into 2 parts.

And some questions:
Did anyone see any temperature probe leads when they opened the battery cases?
Did you see where the other wires go that come from the orange harness loom...the mystery pins (1,7,13,14,18,19,20,24)?


image_pqvfed.jpg
 

w0ss

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Oct 15, 2019
Messages
56
Sojourner said:
A few things...

I did NOT have continuity between the case and the terminals. I only bought one cell. Regretting that now that it seems these units turned out to be pretty good. Paid all that shipping cost for one item...d'oh

When I hooked up a wire harness for BattGo BG-8S (max 8 cell) monitoring, for the first set of 7S (cells 1-7) the black wire went to Pin 2 (Cell1 neg) of the LG connector. Straightforward enough. But for the second set of 7S (cells 8-14), the black wire went to Pin8 (Cell8 neg) to get proper readings for the latter half of the cells. Kind of confusing, until I recalled what w0ss mentioned earlier about the original monitoring board being split into 2 parts.

And some questions:
Did anyone see any temperature probe leads when they opened the battery cases?
Did you see where the other wires go that come from the orange harness loom...the mystery pins (1,7,13,14,18,19,20,24)?


image_pqvfed.jpg
I am going to take mine apart again and try to figure out why I have connectivity. I will look for a temperature probe but I assume they have them on a few of the leads.
 

HydroGeo

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May 7, 2020
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9
I checked my other modules and none had continuity between the case and neg terminal.

I also finished soldering my boards and installed them to check the cell voltages. Everything looks good. The cells provided consistent voltages and appear to be well balanced.

One thing I noticed was that when I attempted to re-install the black, plastic front cover, the U50 and U51 terminals on the board were preventing the cover from fitting properly. I noticed a 1/8 or so gap indicating the terminals are sitting a bit higher relative to the components on the original board. I'm not sure if anyone else has encountered this. I used these terminals from amazon: https://www.amazon.com/gp/product/B00FZLPCKC/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Maybe they are a little taller than other available terminals, not sure. Its not a big deal, I'll just have to modify the cover at some point to make it fit properly... but figured I'd mention it in case others are using the same terminals.
 

w0ss

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Oct 15, 2019
Messages
56
I noticed it was a tight fit as well. I have been trying to think of another way to connect the balance wires. one thought I had was to just solder the wire right to the board.
 

vegburner

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Mar 24, 2020
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10
Hey Murr, i can't send you a pm back, says your pms are disabled. i have 3 spare board if you are in need...
 
Joined
Sep 11, 2020
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2
I purchased 5 of the Lg Chems from the first batch at BH. At that time, there was nothing online about them. Put the project on hold for awhile and delighted to find this thread now.

I was told at by someone at some point it was possible to interface with the existing BMS, and the units would communicate with each other. Doesn't look like anyone has had any luck?

If anyone has any of the custom boards on this thread for sale, I would be interested in purchasing them.
 

floydR

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Joined
Aug 23, 2017
Messages
847
Anyone find a data sheet for the LGX JH3 cell ?
Even the max discharge and max charge amps for the battery packs?
later floyd
 
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