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EG4-LL missing breaker

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moonlight23

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This is a screenshot of Signature Solar's very own video on youtube, you can clearly see it has that white breaker. However on the website it seems like the EG4-LL doesn't have the breaker. Which one is correct?

The EG4-LiFePower4 48v seems like it still has it though. But EG4-LL is the higher end model, shouldn't it include it as well? Are there any technical advantages why there wouldn't be a circuit breaker?
 

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I believe @robby asked this exact question in another battery related thread and never got a response from what i remember. Seems odd they would just stop putting in the breaker since it's such a cheap and easy item to add from the factory.
 
Unless they have a Class-T fuse inside that case (which I doubt) then it means that any kind of mishap like a quick short is going to blow the BMS.
 
robby said:
Unless they have a Class-T fuse inside that case (which I doubt) then it means that any kind of mishap like a quick short is going to blow the BMS.
Click to expand...
What is a "quick short"?

A Class-t fuse will open in ~.01 seconds on a dead short.
A FET based BMS will attempt to open in ~.00001 seconds on a dead short.
If the BMS fails then the class-t fuse will open the circuit.
In either case I would do a functional test of the BMS and replace if necessary.
My BMS cost ~100USD which is about the same as my class T fuse and holder.
I'm happy to replace both if they stop the electrolyte from venting from my LFP cells.
 
We were sent a batch of LL batteries that came with FET based BMS, which is the one on the website currently, but that was an isolated batch. We will be adding the most up to date unit to the website by the end of the week.

The functionality of the battery is still the same. There is still an On/Off switch and we still recommend an inline fuse between battery and inverter just like any other battery.

If you are one of the few that received the LL without a breaker, we are offering $150 credit for the trouble.
 
John Frum said:
What is a "quick short"?

A Class-t fuse will open in ~.01 seconds on a dead short.
A FET based BMS will attempt to open in ~.00001 seconds on a dead short.
If the BMS fails then the class-t fuse will open the circuit.
In either case I would do a functional test of the BMS and replace if necessary.
My BMS cost ~100USD which is about the same as my class T fuse and holder.
I'm happy to replace both if they stop the electrolyte from venting from my LFP cells.
Click to expand...
By Quick short I meant the two wires touching accidentally for a split second.
Yes the FET can most certainly can shutdown faster than a Class-T fuse but that is far from a guaranteed thing.
It all depends on the how well designed the circuitry is for detecting the Short.
I have seen many an RF amplifier that had "protection" and yet the FET's went up in spectacular fashion when they got shorted. It even sent power back through that Gate and damage other parts of the board.

As for the rest of it, I would just like to have a proper built in Class-T fuse and not have to deal with it.
It is disturbing that the bare minimum of a breaker is missing. At least that offers some level of protection.
 
BenFromSignatureSolar I received 6 EG4 LL vs plus a server rack last week. I too noticed that mine DID NOT have the circuit breaker and when I call SS tech support they told me it wasn't necessary. I find that hard to believe but Sean said the on off switch was enough. If the "sale" price of $1600. instead of the regular $1750 was to make up for the mis-shipped breaker less batch you got and sent out, that is not only unethical but possibly illegal. All your EG 4's had the circuit breaker in the past, at least your sales department and website should have noted this. How do I apply for the $150 rebate on each of my 6 batteries?
 
DennisBrady said:
BenFromSignatureSolar I received 6 EG4 LL vs plus a server rack last week. I too noticed that mine DID NOT have the circuit breaker and when I call SS tech support they told me it wasn't necessary. I find that hard to believe but Sean said the on off switch was enough. If the "sale" price of $1600. instead of the regular $1750 was to make up for the mis-shipped breaker less batch you got and sent out, that is not only unethical but possibly illegal. All your EG 4's had the circuit breaker in the past, at least your sales department and website should have noted this. How do I apply for the $150 rebate on each of my 6 batteries?
Click to expand...
Could you DM a picture of the batteries as well as your order number and I will look into this for you.
 
First off, thank you Will Prowse for this forum. Without it I would have not known about this issue I'm going through. Can you please tell me if you think the EG4 LL batteries I purchased from SS that mistakenly came without circuit breakers are safe to use. I'd hate to think that my $10,000.00 investment in these was a big mistake.
 
DennisBrady said:
First off, thank you Will Prowse for this forum. Without it I would have not known about this issue I'm going through. Can you please tell me if you think the EG4 LL batteries I purchased from SS that mistakenly came without circuit breakers are safe to use. I'd hate to think that my $10,000.00 investment in these was a big mistake.
Click to expand...
So after looking at your order. You ordered your batteries as part of the bundle. That was a promotion with a far better discount than the $150 that we were originally offering. Instead of the $1750 that they were originally, you only paid $1512 per battery and received a 6 battery cabinet for no charge. We will not be able to offer an additional $150 rebate on top of that discount.

I know that reading this thread has given you concerns about not having an external breaker. As previously stated, there is no danger or functionality concerns with the FET based protections that are included in this battery. I do hope that @Will Prowse is able to weigh in on the matter so that you aren't just hearing it from me.

Additionally, the 24V V1 is shown to not include a breaker on our site.
 
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BenFromSignatureSolar said:
As previously stated, there is no danger or functionality concerns with the FET based protections that are included in this battery. I do hope that @Will Prowse is able to weigh in on the matter so that you aren't just hearing it from me.
Click to expand...
Oh I would love to hear @Will Prowse weigh in on this!
I guess all those breakers you put on all of your other batteries are put there as a decoration?
I know you try hard to help people and I respect that, but your Boss thinks that he understands electronics, but he does not.
If you told me an internal Class T fuse had replaced the breaker I would say that was an upgrade. To say that no breaker is not an issue and that the Mosfets will handle the problem is completely false!

(I am sure right now Will P. is asking himself why do they always get me involved. Sorry Will, but the Crown is always heavy :LOL: )
 
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First of all I paid $1599. per battery not $1512. And even so, your company offered the promotion I didn't beg for it. You blew it on a number of accounts. If you knowingly were aware that you got a batch of EG4's without breakers you should have noted that in all your ads. Website, email sales flyer, sales department. You were just hoping no one picked up on this. If Jeremy when taking my order would have mentioned the they didn't have breakers I would have passed. If your website and email promotion pointed it out I would also passed. You hid this omission plain and simple. Ben, I assume you asked your higher ups how to handle this so I'm not pissed at you it's them I'm mad at. How is Signature Solar handling all of the others who bought the batteries without breakers? Have you notified them offering the $150 discount? I bet not. I'd bet most of those don't read this forum so the have no idea about this mistake. I hope your legal department is ready to handle a law suit from someone whose house burns down because the FET didn't work. Every business makes mistakes, the ethical ones notify their customers and issue recalls. Not just hope no one notices. You offer is nonexceptable and I'm not going away. Be transparent and prove on this forum that everyone who got these batteries were contacted and offer refunds. Also, please forward me the name of the person where the buck stops.
 
Good discussion. I did talk to Chinese engineers about this a year ago and why they are using AC rated breakers. They said it is not being used as an over current protection device at all, and is only used as a switch. I said they should still use DC breaker and they did, but it technically only served as a switch because the BMS over current is much faster than any breaker out there. So again, completely useless. It should never trip. It's just an on and off switch. That said, they are cheap and I prefer having a large circuit breaker than the tiny switch. But in use, there is no real benefit. I think I made some posts about this a while back when I first found this issue with another company that doesn't sell these batteries any longer.
 
The only benefit I personally see is if it's rated properly for DC, if you have a shorted fet and a shorted battery cell, then the breaker would trip. Very rare occurrence. Not sure how both would happen at same time. But it's nice to have a second layer of protection.
 
Now that I think about it, there is a benefit of removing the breaker. The precharge resistor circuit will be easier to use during system commission without any risk of error (when breaker is attached, you need to follow protocol perfectly or you will expose the fets to inrush). And that is the #1 most common cause of BMS failure. Not having a breaker makes the process fool proof. Turn battery off, connect it, turn battery on. No risk of damage.

What do you guys think?
 
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