Resolved (Ecoworthy Replaced all 4 of the batteries)

[Boron]

This is a must for all Solar nerds at least a 14" size - dont mess with a 6" cheap charlie job for children. When it gets bad you want a one shot slice thru - not failing on half the job, makes matters worse. You are also that much further away from flash damage. Also keep leather gloves to hand and WEAR GOGGLES
Best $20 you 'll be glad you bought. No personal affiliation, just what I got and they work so well and make a very clean cut thru thick cable, like a hot knife thru butter

btw plenty of YT vids showing these in use - then you will see why

 

[AlpineJoe]

Well the mystery of what is underneath the blue heat shrink inside my Eco-Worthy 12V 100AH battery is solved. I opened up all 4 of mine and will add a better monitoring BMS with Bluetooth and display for a 48V Pack. Unfortunately the wouldn't fit in my 19" rack drawer. That would have made a inexpensive enclosure.

That's too bad. I thought they used prismatic in the 12V 100AH batteries. I wonder if my 24V are really pouch even though they said they were prismatic.

 

[BarracudaBob]

That's too bad. I thought they used prismatic in the 12V 100AH batteries. I wonder if my 24V are really pouch even though they said they were prismatic.

I wonder if there is any way to know without opening them up or date? Mine were purchased Dec of 2022

 

[BarracudaBob]

1st responders are making waves. Perhaps it would be safer if we had micro fusion devices, ya they wouldn't like those either.

https://cdllife.com/2024/i-95-shutd...assing-of-battery-transportation-legislation/

 

[mrzed001]

I am seeing these on fleet vehicles, boats, and inverter battery connects. EX to install right on the battery.

MRBF 1 Terminal Stud Fuse Block
View attachment 244480

!!! Do NOT use these for 48V 280Ah+ packs !!!

It has an interrupting capacity of 2000A ... and an LFP pack Isc is about Ah x 10-15
So short circuit of 280Ah pack x 15 = 4200 Asc
This should be the minimum ! (and better to have a bigger safety margin)

 

[mrzed001]

Very interesting case. Been staring at the undamaged battery photo for a while trying to figure out how that main lead would disconnect:
View attachment 244872
What we know is that the balance leads melted, and the main conductor was disconnected. Perhaps one of the negative BMS balance leads (small black leads) were connected to the same terminal as the main negative, and improperly held together. I am thinking solder because a stud and nut would never release it like this. If we could see inside that blue pack, we could figure out what happened.

I have seen some strange solder jobs on cheap packs. I would not be surprised if that main negative was held on with a glob of solder. Very easy for that to come apart if too much current passes through, even for a short time.

Once that main negative was shorted, theres a good chance that all four batteries were supplying current into that spot. Once the other balance leads were involved in the short, lots of heat could be generated. Don't ask me how I know lol those balance leads can be dangerous! and they are bundled up close to each other going into that pack. Lots of heat.

Could have been an internal fault on the BMS. Causing a balance lead to short, but that would not explain why the main negative came off. Unless that short was on the main terminal and there was glob of solder.

Gosh I want to see inside the pack. I wonder if the company can send us pictures of the internals.

What I never see on manufactured packs is FUSE for balance cables.
Every cable can be damaged.
Or even the BMS can be gone and then cells sorted on balance cables (direct short or higher resistance short that lowers the Ampers running on the cables from 4-5000A to 50-200A).

Yep its not easy to fuse the balance cables.
The fuse Aic should be higher than 4000A 70V ... it has to protect against first-last cell short too.
The ceramic 1/4" x 1-1/4" fuses are excellent for these job.

0314005.MXP | DigiKey Electronics

Order today, ships today. 0314005.MXP – 5 A 250 V AC 125 V DC Fuse Cartridge, Ceramic Requires Holder 3AB, 3AG, 1/4" x 1-1/4" from Littelfuse Inc.. Pricing and Availability on millions of electronic components from Digi-Key Electronics.

www.digikey.com

 

[Baz000000]

I'm thankful that I have my batteries and inverter sealed in a metal shed 100ft away from the property so if it ever gets a runaway the house will be OK.

Burning batteries can leave heavy metal deposits that are potentially fatal and can be skin absorbed. Advice is to always make sure you handle with protective gloves and a full hazmat suit with breathing apparatus. There was a report of firefighters in Australia being permanently disabled after tackling an EV fire as all sorts of serious toxins can be in the smoke. In the moment though, its probably just going to be a grab it and run.

 

[upnorthandpersonal]

What I never see on manufactured packs is FUSE for balance cables.

The balance cable is the fuse

 

[BarracudaBob]

!!! Do NOT use these for 48V 280Ah+ packs !!!

It has an interrupting capacity of 2000A ... and an LFP pack Isc is about Ah x 10-15
So short circuit of 280Ah pack x 15 = 4200 Asc
This should be the minimum ! (and better to have a bigger safety margin)

Good to know! So far I have only seen them on 12V systems.

 

[SparkyJJO]

!!! Do NOT use these for 48V 280Ah+ packs !!!

It has an interrupting capacity of 2000A ... and an LFP pack Isc is about Ah x 10-15
So short circuit of 280Ah pack x 15 = 4200 Asc
This should be the minimum ! (and better to have a bigger safety margin)

What if you stack 4 of them together?

 

[BarracudaBob]

What I never see on manufactured packs is FUSE for balance cables.
Every cable can be damaged.
Or even the BMS can be gone and then cells sorted on balance cables (direct short or higher resistance short that lowers the Ampers running on the cables from 4-5000A to 50-200A).

Yep its not easy to fuse the balance cables.
The fuse Aic should be higher than 4000A 70V ... it has to protect against first-last cell short too.
The ceramic 1/4" x 1-1/4" fuses are excellent for these job.

0314005.MXP | DigiKey Electronics

Order today, ships today. 0314005.MXP – 5 A 250 V AC 125 V DC Fuse Cartridge, Ceramic Requires Holder 3AB, 3AG, 1/4" x 1-1/4" from Littelfuse Inc.. Pricing and Availability on millions of electronic components from Digi-Key Electronics.

www.digikey.com

A lot of commercial equipment I see uses the Pico Fuse on PCB or on the wire under heat shrink. Just a nick on a balance wire and it is all over.

 

[BarracudaBob]

What if you stack 4 of them together?

I could see them on 100ah on 51.2V, SOOO convenient

 

[Boron]

I'm thankful that I have my batteries and inverter sealed in a metal shed 100ft away from the property so if it ever gets a runaway the house will be OK.

Burning batteries can leave heavy metal deposits that are potentially fatal and can be skin absorbed. Advice is to always make sure you handle with protective gloves and a full hazmat suit with breathing apparatus. There was a report of firefighters in Australia being permanently disabled after tackling an EV fire as all sorts of serious toxins can be in the smoke. In the moment though, its probably just going to be a grab it and run.

IIRC its the HF gas produced that is the worst , its one of the most toxic gases on the planet even at ppm levels. If you smell it you are dead

 

[Boron]

What if you stack 4 of them together?

IMHO these fuses should not be used above 12Vdc

 

[SparkyJJO]

IMHO these fuses should not be used above 12Vdc

If you couldn't tell by the face I used, I wasn't being serious. I have a class T for 48V (and a MCCB with 25kA AIC).

 

[Boron]

IMHO these fuses should not be used above 12Vdc

Stacking is just same as parallel, small residual gap is just the same - you did think of that didnt you

 

[SparkyJJO]

Stacking is just same as parallel, small residual gap is just the same - you did think of that didnt you

No. Putting them in series, not parallel. Still, I wasn't being serious. Lighten up

 

[Boron]

What I never see on manufactured packs is FUSE for balance cables.
Every cable can be damaged.
Or even the BMS can be gone and then cells sorted on balance cables (direct short or higher resistance short that lowers the Ampers running on the cables from 4-5000A to 50-200A).

Yep its not easy to fuse the balance cables.
The fuse Aic should be higher than 4000A 70V ... it has to protect against first-last cell short too.
The ceramic 1/4" x 1-1/4" fuses are excellent for these job.

0314005.MXP | DigiKey Electronics

Order today, ships today. 0314005.MXP – 5 A 250 V AC 125 V DC Fuse Cartridge, Ceramic Requires Holder 3AB, 3AG, 1/4" x 1-1/4" from Littelfuse Inc.. Pricing and Availability on millions of electronic components from Digi-Key Electronics.

www.digikey.com

I was thinking that std ATO wafer fuses would do the job if needed (in practice this is never done it seems even though the wires only ever see ca 3V and <5A? is that right?) but it is important not to leave flimsy wires trailing across battery busbars or steel struts, bundle them up tidy in that spiral cable harness stuff

 

[Boron]

No. Putting them in series, not parallel. Still, I wasn't being serious. Lighten up

Those floating members here dont think its funny. A poster pointed out that he is limited to what he can get for spare parts (Class T is a joke) and also he doesnt want false trips - a fuse should only trip as a last resort, the priority is often to maintain power supply under potentially adverse conditions. Floaters have lived with this for decades - study the ABYC forum

 

[Blakes]

!!! Do NOT use these for 48V 280Ah+ packs !!!

It has an interrupting capacity of 2000A ... and an LFP pack Isc is about Ah x 10-15
So short circuit of 280Ah pack x 15 = 4200 Asc
This should be the minimum ! (and better to have a bigger safety margin)

I have this type of fuse on the main + terminal on my system. 4 chins 12.8v 200ah wired in series. I do not have any fuses between each of the batteries. Should I places fuses between each 12.8v battery? Should I switch the main fuse to another type?

This happily runs my offgrid log cabin that I built/wired/plumbed and live.

All 4 of these batteries are sitting on bare concrete in my underground basement that stays at ~50 F.

 

[labeeman]

I have this type of fuse on the main + terminal on my system. 4 chins 12.8v 200ah wired in series. I do not have any fuses between each of the batteries. Should I places fuses between each 12.8v battery? Should I switch the main fuse to another type?

This happily runs my offgrid log cabin that I built/wired/plumbed and live.

All 4 of these batteries are sitting on bare concrete in my underground basement that stays at ~50 F.

Waste of money and time one fuze in a series circuit is all that is needed.

 

[Boron]

Hmm so you are just using a single MRBF type that sits on the battery lug? at 48Vdc. IMHO it would not give me comfort but then I am deeply suspicious of the whole rotten industry anyway. I would go back to basics and string a piece of copper wire between two m8 brass posts on a block of rockwool or non inflammable support with at least 3 inches separation. Choose a wire gauge suitable for your normal load current (you can string several strands together to make up a size - look up tables on google for fusing current you want to be say 3x higher than load current assuming your down stream wiring is ok with short term spikes). Then you must contain the explosive vapour fragments at your choice - sand is favoured - say a channel section filled with dry silver sand, or a ceramic tube say filled with sand. Put the whole assembly inside a brick trough to smother any flying sparks.
Or you might go real old school and dig out one of those bulky cast iron switchfuse boxes with rewireable fusewire carriers. They were big like that for a good reason. I like big knife switches

But I will probably be shot down here in flames for preaching heresy

 

[Boron]

Of course YMMV and bottom line, whatever you choose you must test it out under sc fault event, dont wait for the worst case as you may have a false sense of security to burn your house down. LV high current systems are mostly unchartered territory for average Joe so the fusible weak link is a fundamental safeguard - not rocket science. Its what Ford and GM did with their autos in the 30's. Marketing mongrels found ways of making it all miniature and convenient with buzz words to add $$$ to what is a thin piece of wire

 

[SparkyJJO]

I'd rather use something tested and known to blow at X amperage with Y breakable current at Z volts. More power to those who can do their own and trust it, but I don't trust myself enough to build my own fuse lol

 

[cs1234]

1st responders are making waves. Perhaps it would be safer if we had micro fusion devices, ya they wouldn't like those either.

https://cdllife.com/2024/i-95-shutd...assing-of-battery-transportation-legislation/

It would be nice if we could get them to stop lumping all lithium chemistries together when discussing them and talking about regulations. They are not all the same.