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EG4 LL Battery Discharging and Charging Slower Than The Rest

robby said:
Seriously Will! You had a bad experience with Lishen cells leaking and that condemns the whole process of testing batteries for 30 days plus X-Raying , weighing them and measuring there electrical characteristics for inconsistencies? It's all useless in your opinion?
These kinds of certificates are how we are able to sustain work flow in the industry. It gives us confidence that the products we are using conform to the standards we expect. And NOBODY in the industry just follows them blindly. You would be a fool to be in the EV industry and not have several employees that randomly pull out packs in each shipment and run them on $10,000 machines to measure all of their electrical parameters etc. I would suspect they also will X-Ray some sample batteries and they are all weighed etc. The information is matched against the certificates and if it is not reasonably matched then the whole order will be further examined and most likely returned.

We certainly tested sample batches of all the products we had made. Pulling them apart and checking every component for substitutes and using microscopes to view soldering joint and traces for defects. We would even desolder large electrolytic capacitors and check them to make sure they met the specifications listed on the manufactures charts. We suspected labels could be fabricated on parts and this was actually tried on a few occasions

As for your Lishen cells leaking, that is probably not an issue that could be tested for. The battery probably pasts every test, it's just that the material holding the cell together is faulty or the chemical composition of the electrolyte is to corrosive. That is no different than the Capacitor Plague of the late 1990's when the market got flooded with bad Capacitors for 6 years from all the major Taiwanese manufactures.

I worked with those Capacitors and they tested normally and they worked normally but after the product was out in the public's hands for 1-2 years the Capacitors would start leaking all over the circuit boards.
It was found out almost a decade later that it was a faulty formula in the electrolyte that had been given to a Chinese Spy working at Rubycon in Japan. His job was to figure out why their capacitors were superior and when he realized it was the Electrolyte the company covertly let him get access to a formula, but it was actually a formula that they had failed testing because it had major long term issues. They knew he would take the formula back to China and Taiwan and pass it on to their competitors and that's exactly what he did. They then used the bad formula in all their capacitors for around 5 years and anyone who bought them ended up with lots of warranty returned items.


You keep saying that but is there any real world data that shows that to be true? I have seen a guy on here showing off an LFP battery bank that is 15 years old and it is still working fine.

Yes there is always a difference but that is a vague statement. The tolerance values in a matched set of cells used by a Tier one company will be very tiny as compared to a company that just randomly throws Grade B cells into a pack. You should charge up that eFlex and monitor the cells and then compare it with an EG4LL and see the difference. You will find the eFlex has a very slight deviation as it charges while the EG4LL has a huge deviation.
Yes at the end of the day the EG4LL balances out the cells but you have to wonder about the longevity of those cells that are always going high.

Yes one cell will always reach there first. What I don't expect is for three to get to 3.75V when the others are at 3.35V. I also don't expect it to be the same cells doing it all the time. That tells me that those cells are significantly different than the other ones in the pack.

I don't remember mentioning a firmware difference or any complaints about the BMS. I will have to look back through the posts.

The eFlex battery does not have that issue unless you want to nit pick. As I said it's all about matching and the tolerances that are accepted.
All the cells will have slightly different ESR and capacity but if they are all producing good numbers and then batched together properly it will be very small differences.

Agree but I would add that the warranty is only as good as the company that stands behind it. We have already seen threads hit 900 posts with one guy trying to get warranty service on a battery that simply did not work with his Inverter. I would hate to be trying to prove my capacity has dropped by 20% when a video of switching something on and it not working has been proven to be insufficient evidence to get warranty help.



That's the big question! Lots of things work perfectly in the short term, but the long term is where the difference lies. I just finished working on my 14 Month old GE Washing Machine. Replaced a Burned out drain Pump and as soon as I put my ohm meter on it and got 9 ohms my heart sunk because the new pump measured 40 ohms.
Sure enough the motor control board is also dead. Why is it we can't make appliances that last anymore?
My old washing Machine lasted for 15 years with only minor issues.


Your swimming in batteries so I get your line of thinking, but for someone like me that wants a pack of batteries to last 10-12 years I am not going to turn a blind eye to so many leading people in the industry saying that cells in battery packs are not all the same. If it's anything like I suspect it is, I doubt that even one production run of packs is the same as another. I suspect it's all dependent on what batteries they can get for the price point they are trying to buy them at.

That's not as easy as you might think because these batteries are running the power in my house 24/7.
Click to expand...
I don't think you're disagreeing with me here. I like the certification process but I always question any of them due to my bad experiences. And I think your pack will last 12 years without any problems. I know you're running your pack 24/7 and I was 100% Offgrid for ten years, so I get it. Charge up to 100% then do a cycle, and try to time discharge to 0% when the sun comes up. I've had to do that many times. Not that easy but that's the only way you'll know. Need to find a way to assess capacity or else you won't have a clue.

And yes the warranty is as good as the company. These companies are accumulating capital quick and have good sales, they should be around for a while. But who knows. Just takes a few bad decisions to kill a company so who knows.

And I don't think of any of these batteries as special. Or "tier one" as you stated. They are all the same cells from a few suppliers, and I open them every single day. Just opened a battery this morning that didn't have the top glued on haha! I don't care how fancy these batteries are, I don't trust what anyone says about them. What matters most is selling thousands of packs and see which ones survive.

And yes the more expensive packs have cells that hit 3.7-3.8V. goes away pretty quickly and I have seen it so many times that I'm not too concerned.
 
Hey robby, maybe you can give his guy some pointers:
diysolarforum.com

Signature Solar 24v EG4-LL unbalanced and Low capacity with SoC at 100%

I installed 3 EG4-LL batteries about a month ago in my cabin and I didn’t have any issue until today. When I arrived today, I looked at my batteries state to see how they are doing. SoC is at 100% for all three. Two seem in a perfect state but one is showing a cell OV status, low capacity...
diysolarforum.com diysolarforum.com
 
Alkaline said:
Hey robby, maybe you can give his guy some pointers:
diysolarforum.com

Signature Solar 24v EG4-LL unbalanced and Low capacity with SoC at 100%

I installed 3 EG4-LL batteries about a month ago in my cabin and I didn’t have any issue until today. When I arrived today, I looked at my batteries state to see how they are doing. SoC is at 100% for all three. Two seem in a perfect state but one is showing a cell OV status, low capacity...
diysolarforum.com diysolarforum.com
Click to expand...
Yes I contacted him thanks. I also had this issue again last week and it's getting very tiring having to get the cells balanced again. If I don't isolate the pack and bump up the charge voltage it will never get past 91% SOC when it settles. Once I go through an hour of slightly higher voltages the cells balance out again and stay that way for several weeks until it happens again.
 
robby said:
Yes I contacted him thanks. I also had this issue again last week and it's getting very tiring having to get the cells balanced again. If I don't isolate the pack and bump up the charge voltage it will never get past 91% SOC when it settles. Once I go through an hour of slightly higher voltages the cells balance out again and stay that way for several weeks until it happens again.
Click to expand...
What kind of BMS do you have?

Do you also have an active balancer?
 
robby said:
Yes I contacted him thanks. I also had this issue again last week and it's getting very tiring having to get the cells balanced again. If I don't isolate the pack and bump up the charge voltage it will never get past 91% SOC when it settles. Once I go through an hour of slightly higher voltages the cells balance out again and stay that way for several weeks until it happens again.
Click to expand...
My Trophy 220 does the same.
 
cdsolar said:
So what is the answer? What BMS do eg4 LL V2 batteries use?
Click to expand...
Everytime I hear @Will Prowse mention it he says "it's using the same BMS as all the others" but I am yet to hear from someone what Brand and model BMS is it that most of these rack mount batteries are using.
 
robby said:
Everytime I hear @Will Prowse mention it he says "it's using the same BMS as all the others" but I am yet to hear from someone what Brand and model BMS is it that most of these rack mount batteries are using.
Click to expand...
I know that SOK has made a point that their bms is a different design from a different company than the bms used in the eg4 . I wish we could get more information on the different bms's used in the rack style batteries.

I wonder if any of them offer active balancing?
 
Will Prowse said:
Friend told me a month ago. Will ask them. It's one manufacturer
Click to expand...
Will,

The EG4 LLv2s may be a different BMS from the LLv1s as the V2s are advertised as capable of interfacing with different vendor's inverters via a change on the LCD screen.

Chris
 
cdsolar said:
Will,

The EG4 LLv2s may be a different BMS from the LLv1s as the V2s are advertised as capable of interfacing with different vendor's inverters via a change on the LCD screen.

Chris
Click to expand...
'Different?'
When do we define the BMS as 'different'?

1) Same hardware but different Firmware?​
2) New rev of the hardware that has minor tweaks/fixes?​
3) Completely different hardware?​

In most of the server-rack battery market, they have the 'same' BMSs but items 1 & 2 are happening at a reasonably fast pace. Consequently, even the same model battery that is built at a later date may not have the exact same BMS hardware and firmware.

I suspect that the difference in the BMS between the EG4LL V1 and V2 is not a totally different BMS but has a few HW tweaks and new firmware.

I am really glad that EG4 has a clear differentiation between V1 and V2. Sometimes the hardware changes without a clear delineation of the model naming and we are left with 'old versions' and 'new versions'. If we are lucky, the manufacturer will provide this information based on serial number or build date.... but even that is often not available.
 
FilterGuy said:
'Different?'
When do we define the BMS as 'different'?

1) Same hardware but different Firmware?​
2) New rev of the hardware that has minor tweaks/fixes?​
3) Completely different hardware?​

In most of the server-rack battery market, they have the 'same' BMSs but items 1 & 2 are happening at a reasonably fast pace. Consequently, even the same model battery that is built at a later date may not have the exact same BMS hardware and firmware.

I suspect that the difference in the BMS between the EG4LL V1 and V2 is not a totally different BMS but has a few HW tweaks and new firmware.

I am really glad that EG4 has a clear differentiation between V1 and V2. Sometimes the hardware changes without a clear delineation of the model naming and we are left with 'old versions' and 'new versions'. If we are lucky, the manufacturer will provide this information based on serial number or build date.... but even that is often not available.
Click to expand...
Very good question because the firmware can actually be significantly different. And the display. But the BMS hardware is the same it seems. I need to open some up because I remember seeing the same serial number on a few server rack BMS. But yes, the firmware and what it connects to can vary significantly.
 
Will Prowse said:
.....and what it connects to can vary significantly.
Click to expand...
That is a good point. The BMS could be exactly the same between two different batteries but could be wired differently, resulting in different 'features'.
Just a few of the things that could be different:
* Number of temp sensors installed
* Heating pads installed or not
* Bluetooth dongle installed or not
* What comms ports are hooked up (or even the pinout of the coms ports)
 
Will Prowse said:
Very good question because the firmware can actually be significantly different. And the display. But the BMS hardware is the same it seems. I need to open some up because I remember seeing the same serial number on a few server rack BMS. But yes, the firmware and what it connects to can vary significantly.
Click to expand...

Will Prowse said:
Very good question because the firmware can actually be significantly different. And the display. But the BMS hardware is the same it seems. I need to open some up because I remember seeing the same serial number on a few server rack BMS. But yes, the firmware and what it connects to can vary significantly.
Click to expand...
Agreed that 'different' may 'only' be firmware, but the difference may be feature rich.
 
If I had to guess, I think the EG4 LLv2 uses Seplos. Andy from Off Grid Garage has a video that shows a PC interface to a Seplos BMS that has the same set of inverters as options that the EG4 LL2 LCD screen has.

Of course I could be completely wrong. But if I were to guess with limited information, that's what I would guess.

-Chris
 
cdsolar said:
If I had to guess, I think the EG4 LLv2 uses Seplos. Andy from Off Grid Garage has a video that shows a PC interface to a Seplos BMS that has the same set of inverters as options that the EG4 LL2 LCD screen has.

Of course I could be completely wrong. But if I were to guess with limited information, that's what I would guess.

-Chris
Click to expand...
given the numbers of utp and rs232 connector i highly doubt it.
seplos has only 3 ports :
inverter port ( labelled CANBUS, but as of the "e" version both rs485 and CANBUS)
rs485 a and rs485 b ( only to be used for monitoring software/inter bms comma)

but could be wrong here.
there is also the possibility it is a self developped bms by a manufactorer that i am not aware of
 
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