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diy solar

House burned down

SparkyJJO said:
Call me weird but I don't want a Seplos BMS. I keep seeing where they mess with it and v3 is not as good, or something. I dunno.
Part of me wants to get JK BMSes, another part just wants to retain the JBDs I have (with 300A contactors LOL overkill) just because I own them already.

Maybe all it would take to make it "work" with 230Ah is to just put a spacer block in the back of the case to account for thickness difference. I should check cell dimensions.

I'll take my discussion to the Luyuan battery box thread as to not junk up this one with my ramblings and musings.
Click to expand...
Again, this is not about the BMS....
 
What if 1 hot cell started melting the plastic wrapper, shorting 2 cells case-to-case? A chain reaction could commence shorting one to the next as the heat grew.
 
bolhuijo said:
What if 1 hot cell started melting the plastic wrapper, shorting 2 cells case-to-case? A chain reaction could commence shorting one to the next as the heat grew.
Click to expand...

Has anyone actually verified that the case is a direct connection to one of the electrodes? I tested the original EVE 280 cells way back when, and that was just a capacitive coupling, there was barely any current flowing from case to terminal. I have tested this with other cells as well, with the same result, but this test was not exhaustive. Which cells have a direct connection between one of the terminals and the case?
 
SparkyJJO said:
Call me weird but I don't want a Seplos BMS. I keep seeing where they mess with it and v3 is not as good, or something. I dunno.
Part of me wants to get JK BMSes, another part just wants to retain the JBDs I have (with 300A contactors LOL overkill) just because I own them already.

Maybe all it would take to make it "work" with 230Ah is to just put a spacer block in the back of the case to account for thickness difference. I should check cell dimensions.

I'll take my discussion to the Luyuan battery box thread as to not junk up this one with my ramblings and musings.
Click to expand...
And to add, this is now the third time we've seen something like a fire or a burn where this BMS was involved..

The first one : cheap powerwall, not build according to spec and leaky cells, yet the BMS was blamed at first

Second one, was a axepium box ( mason 280k rebadge)
Turn out a manual instruction issue and missing crush rings..
Again BMS was blamed until details came out

Here we don't know what exactly went down, and it is all speculation..

Weather this was an internal shorted cell or a fuse that arced, or simply wrongly assembled packs...

Untill we have more info we will not know, but it is all too easy to blame the BMS yet again, most likely wrong again
 
WindWizard said:
This is my summary of the fire. The Cells are arranged in 16s x 6 with fuses between each bank. After the fuses the banks are then connected together with a copper busbar. In order for one of the fuses to blow, then there would need to be current flow of in excess of 200 amps. The fuses were not type T fuses, so once the fuse melted then it continued to arc causing a fire.

The root cause would have to be one of the Cells that became shorted. That would drop the voltage down so that the current would flow from the other 5 banks to the bank with the defective Cell.

There was an indication of issues with the Cells from Xuba from the leaking Cells. The leaking Cells were replaced, but there were possibly others that just needed to have more time before they went.

The Cell that became shorted would have had to be a sudden event. The system had been working fine for years, and was working fine the day of the event. It wasn't until the sun had gone down and the system was in discharge mode, that the event occurred.

The system was put together in a meticulous manner and a lot of thought on safety was evident in the displayed results.

The Cells were all on a metal shelf and monitored, and still his house is destroyed.

This is all speculation, of course.

I believe that how we treat our Cells is very important. The Cells should be treated gently and not abused by excessive charging or discharging, above or below the knee.

Regular Cell monitoring and balancing should be a daily regime.

My thoughts are that LFP technology is still one of the safest Cell technologies that we have. This is evident in the direction of EV manufacturing. It also makes me question some of the Cells that do not make it to EV quality. Are we risking our homes to save a few bucks?

My conclusion is that the only way to be entirely safe is to remove the hazard from your home.
Click to expand...


The pictures only show 6 strings, but in the build string where he replaced the leaking cells he shows where he had 7 strings made with 112 280ah cells. Also if you read the whole thread where he is building out his battery banks he started in a black metal cabinet then moved to a long wall of cells.

So 7 strings * 16 cells all using cell top balancers controlled by a single BMS. Interesting way of doing it but has the benefit of one controller keeping all 112 cells balanced. And the balance leads don't need any special identical length because the cell top balancer just lets through enough current to do the job. I believe he is using a 2 amp model of this.



I agree it was likely a venting cell that caused overcurrent to blow a fuse that caught on fire providing the spark.
 
Last edited:
houseofancients said:
And to add, this is now the third time we've seen something like a fire or a burn where this BMS was involved..

The first one : cheap powerwall, not build according to spec and leaky cells, yet the BMS was blamed at first

Second one, was a axepium box ( mason 280k rebadge)
Turn out a manual instruction issue and missing crush rings..
Again BMS was blamed until details came out

Here we don't know what exactly went down, and it is all speculation..

Weather this was an internal shorted cell or a fuse that arced, or simply wrongly assembled packs...

Untill we have more info we will not know, but it is all too easy to blame the BMS yet again, most likely wrong again
Click to expand...
I'm not blaming the BMS.
I'm just saying I don't want a Seplos BMS for other reasons.
 
houseofancients said:
And to add, this is now the third time we've seen something like a fire or a burn where this BMS was involved..

The first one : cheap powerwall, not build according to spec and leaky cells, yet the BMS was blamed at first

Second one, was a axepium box ( mason 280k rebadge)
Turn out a manual instruction issue and missing crush rings..
Again BMS was blamed until details came out

Here we don't know what exactly went down, and it is all speculation..

Weather this was an internal shorted cell or a fuse that arced, or simply wrongly assembled packs...

Untill we have more info we will not know, but it is all too easy to blame the BMS yet again, most likely wrong again
Click to expand...


He is not using a traditional BMS.


Everyone should read this entire thread before commenting on the BMS or other things to do with the battery cells.

diysolarforum.com

LFP Powerwall

a few pictures of my own built 'home energy system'. I run my house, workshop and if needed charge my tesla model S with it. currently 3 multiplus 2 5 kVa units for 3-phase system, 48 V battery: 3 banks of 16 200 Ah cells, monitored by batrium. The victron system runs the ESS template. One of...
diysolarforum.com diysolarforum.com
 
robbob2112 said:
The pictures only show 6 strings, but in the build string where he replaced the leaking cells he shows where he had 7 strings made with 112 280ah cells. Also if you read the whole thread where he is building out his battery banks he started in a black metal cabinet then moved to a long wall of cells.

So 7 strings * 16 cells all using cell top balancers controlled by a single BMS. Interesting way of doing it but has the benefit of one controller keeping all 112 cells balanced. And the balance leads don't need any special identical length because the cell top balancer just lets through enough current to do the job. I believe he is using a 2 amp model of this.



I agree it was likely a venting cell that caused overcurrent to blow a fuse that caught on fire providing the spark.
Click to expand...
Effectively, 7-15kwh batteries using all one singular BMS? That doesn’t sound fun at all
 
rhino said:
It's a Batrium, they are designed for that and more.
Click to expand...
I don't think running seven strings in parallel like was being done is a supported configuration from Orion. I believe they would spec one watchmon and shunt per string, not one watchmon and then multiple parallel strings.
 
I don't really know much about Orion Batrium but my understanding is per normal specification each string of 16 cells would have a watchmon, and multiple blockmons, and a shunt. If there's an issue with a cell in the string the shunt will open and that battery is isolated.
 
rhino said:
It's a Batrium, they are designed for that and more.
Click to expand...
Using 112 Blockmons (one on each cell) to a single Watchmon still does not sound fun.

Here’s the wiki for just the Blockmon, this wiki makes me now ponder more possibilities of the OP set up and potential failure points.

BlockMon

How to wire the BlockMon Cell Monitor, with wiring diagrams and features.
wiki.batrium.com wiki.batrium.com
 
This gives me an idea how to better protect parallel batteries. Install current shunt or hall shunt and contactor on each series string. If current sharing suddenly deviates from equilibrium then disconnect offending string. Doing this prevents other good strings from dumping current into shorted string. The hardware to do this already exists on rack batteries in their BMS boards making this only a question of firmware modification.
 
Supervstech said:
I am glad i have my thermal imaging attachment on my ipad.
It is an invaluable tool for stress testing builds.

They arent cheap, but they are amazing and im thinking a DIY necessity.
Click to expand...
I bought a flir, but what is considered "hot"?
 
G00SE said:
Batrium has a 17 page document specifically about parallel systems

In the OP build thread @Ampster says he too was running a single batrium on 2 packs and was facing some difficulty. Idk what his resolution was, but at the time he mentioned adding more BMS instead of sharing
Click to expand...
Almost every page of that document warns against running multiple strings in parallel without taking specific safety measures to be able to disconnect each string automatically, the section about the dangers of eddy currents foresees an issue where a single cell failure could cause a cascading issue that moves from string to string.

Screenshot_20240430_165531_Samsung Notes.jpg

Screenshot_20240430_165938_Samsung Notes.jpg
 
Brucey said:
Almost every page of that document warns against running multiple strings in parallel without taking specific safety measures to be able to disconnect each string automatically, the section about the dangers of eddy currents foresees an issue where a single cell failure could cause a cascading issue that moves from string to string.

View attachment 212509

View attachment 212510
Click to expand...



Which brings us full circle back to the idea of


Cell shorted/vented for unknown reason, fuse blew/melted/caught on fire, then everything went out of control.


OP was using the fuse type that Victron recommended.

I think we as a group generally think a class T on each string would have let the bad cell fail without taking all the other strings and the house with it.

Many possible causes of the cell vent, no way to dig any deeper with what is left
 
AntronX said:
This gives me an idea how to better protect parallel batteries. Install current shunt or hall shunt and contactor on each series string. If current sharing suddenly deviates from equilibrium then disconnect offending string. Doing this prevents other good strings from dumping current into shorted string. The hardware to do this already exists on rack batteries in their BMS boards making this only a question of firmware modification.
Click to expand...
Batteryhookup has the tyco 500A relays for peanuts if you weren't aware, they have a version with fuse already attached sometimes.

batteryhookup.com

TE Connectivity EV200AAANA 500a 0-900vdc Tyco 12/24v

These were recovered from EV battery modules. These are VERY EXPENSIVE online. If you have any project that needs a high current relay this is your chance to save some money. Make a cheap 30a BMS into a 500a BMS. This will work for batteries in the 9-36v range so perfect for Lifepo4 and Lithium...
batteryhookup.com batteryhookup.com
 
Brucey said:
Batteryhookup has the tyco 500A relays for peanuts if you weren't aware, they have a version with fuse already attached sometimes.

batteryhookup.com

TE Connectivity EV200AAANA 500a 0-900vdc Tyco 12/24v

These were recovered from EV battery modules. These are VERY EXPENSIVE online. If you have any project that needs a high current relay this is your chance to save some money. Make a cheap 30a BMS into a 500a BMS. This will work for batteries in the 9-36v range so perfect for Lifepo4 and Lithium...
batteryhookup.com batteryhookup.com
Click to expand...


you must be listening to @timselectric - he is the contactor king.
 
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