*Update again, replaced* EG4 Wall Mount battery cell not reaching absorb voltage.

[fnnwizard]

Alright, been a minute, I know.

So, I have exchanged lots of emails with the EG4 reps, and apparently, per them, the only way to get the BMS to do a top balance is to set off the over voltage alarm, which, is 3.8v per cell. Or 60v for the battery. They said doing that briefly is fine and won’t harm the batteries. I believe only about 6 amps was going to the each battery at the time.

They had initially told me 3.7v per cell, but apparently were using outdated information. I had even told them it says in my basic manual that the over voltage alarm was listed at 3.8v.

So, I did that at their explicit instruction and got all three of my batteries to get to that event, although only one has the cell that is slowly falling out.

So, we’ll see if that causes it to slowly correct the cell that isn’t charging all the way.

My Post 22 & 36 is the way to start the balancing process. EG4 has no fricking clue!!! I've written this many times already. I really wish they learn.

At 6A, you are just about into overcharging territory at 3.5V , so going from 3.5->3.8 is a few minutes of which at somewhere around 150mA balancing gives really nothing vs staying at 3.5V...

They mentioned going there briefly.... no, it'll have to go there many hrs.

What is the lowest cell V when the highest is at 3.55V? That is the key info to find out 1st.

The smart way to balance is to start at the lowest pack V possible, not to drive a cell to 3.8V... arhggg.

 

[Zapper77]

Alright, been a minute, I know.

So, I have exchanged lots of emails with the EG4 reps, and apparently, per them, the only way to get the BMS to do a top balance is to set off the over voltage alarm, which, is 3.8v per cell. Or 60v for the battery. They said doing that briefly is fine and won’t harm the batteries. I believe only about 6 amps was going to the each battery at the time.

Please let me know who you talked to at EG4 and I'll figure out why they said 60v.

What is the voltage delta between the highest and lowest cell when they are fully charged and what was the total pack voltage?

 

[fnnwizard]

Please let me know who you talked to at EG4 and I'll figure out why they said 60v.

What is the voltage delta between the highest and lowest cell when they are fully charged and what was the total pack voltage?

It would go a long way if you guys post a sticky to help EG4 users.
Of course that would also mean that you have to know your products very well and basic LiFePO4 operation.

Need to break down the BMS default settings and how they interact with EG4 inverters through:
1. Lead acid : system, absorb, float V settings
2. SOC
a. SOC - there are some inverter defaults that reference SOC#s a lot of users don't know and not described in the manuals.
b. V - same here. in this mode, there are also some inverter defaults that references SOC #s even in V mode. SOC supposed to be ignored.

 

[IAm_Not_Lost]

Please let me know who you talked to at EG4 and I'll figure out why they said 60v.

What is the voltage delta between the highest and lowest cell when they are fully charged and what was the total pack voltage?

I have exchanged emails with a few people. The latest was Leila Calvillo. They specifically instructed me to set off the over-voltage alarm by getting one of the cells to 3.8v. There were quite a few emails before that, and different voltage thresholds recommended, but basically, all of them were just trying to have me get the batteries into a state of brief over voltage protection.

Basically that appears to be their solution for any top end imbalance is to set off the over voltage protection and that is supposed to prompt the BMS to begin balancing on future charging.

The delta between the highest cell and the cell that is low at the time of full charge is about 125-150mV during a normal absorb charge. Total pack voltage is at around 56v.

 

[wpns]

Basically that appears to be their solution for any top end imbalance is to set off the over voltage protection and that is supposed to prompt the BMS to begin balancing on future charging.

Well, not _impossible_, though I've never heard of such a thing. EG4/SS has such a poor understanding of the firmware in their products that it's not inconceivable. I mean, it's also entirely possible that someone misunderstood something and passed it on to you as the gospel truth. #PlayingTelephone

 

[fnnwizard]

The delta between the highest cell and the cell that is low at the time of full charge is about 125-150mV during a normal absorb charge. Total pack voltage is at around 56v.

Need to know hi cell V and lo cell V to be accurate. But based on your 1st post and these extra bits of info. I estimate you are 10-15% imbalance.

The chart below gives a possible scenario of your cells with "around" the 56V you described.

The 3.520 column could be as high as 35% off, while the 3.65V would be less than 0.1%.

 

[TM48]

If you set your voltages to what the manufacturer recommends the battery will stay in balancing longer and should self correct.

 

[Zapper77]

Well, not _impossible_, though I've never heard of such a thing. EG4/SS has such a poor understanding of the firmware in their products that it's not inconceivable. I mean, it's also entirely possible that someone misunderstood something and passed it on to you as the gospel truth. #PlayingTelephone

Easiest way to trigger 100% SOC is Cell OV.
Cell imbalance is a different issue.

 

[IAm_Not_Lost]

If you set your voltages to what the manufacturer recommends the battery will stay in balancing longer and should self correct.

My charge controllers have been set to exactly what the manufacturer (or at least EG4) recommends since I got them. The only variation has been at their recommendation.

 

[wpns]

Easiest way to trigger 100% SOC is Cell OV.
Cell imbalance is a different issue.

Sorry, but IMHO that's a completely broken paradigm. Especially the EG4 WallMounts, the easiest way to reach 100% SOC (and reset the coulomb counter) is (*) to hit 56.5(ish) volts and/or cell voltages of 3.525(ish) volts.

You should never hit COVP, that's an indication that something's seriously wrong, so the BMS shuts off the charge FETs. Unless you've been using the BMS as a charge controller, and have stressed the FETs so much that one or more of them has shorted, and then it _can't_ disconnect, so your battery catches fire instead. So maybe 'battery caches fire' is the tertiary safety disconnect mechanism?

(*) EG4/SS isn't saying, probably because they don't know, but that's about when all mine reset to 100%

 

[wpns]

My charge controllers have been set to exactly what the manufacturer (or at least EG4) recommends since I got them. The only variation has been at their recommendation.

Yeah, but again, EG4/SS doesn't know themselves, and they don't have the source code for the firmware (which is a real mess, see the many EG4PPWM firmware threads), so their recommendations are based on what someone from the Elbonian firmware developers told the white-box manufacturer who told someone at EG4 who told someone at SS who mentioned something to (each tier of SS tech support) in a long and tortuous game of https://en.wikipedia.org/wiki/Telephone_game

If you understand LFP cells and batteries (as @fnnwizard clearly does), you'll know why the EG4/SS recommendations don't make any sense. Again, it's entirely possible (however unlikely) that there's code in the batteries that resets <something> when you hit COVP to (re)enable balancing, but given the above, it's more likely to be Magical Thinking ("Last time I did this on a Thursday and it worked, so in order for it to work, you must do it on a Thursday") but if you never hit the balance threshold, you'll never do any balancing. Do you have the cables to talk directly to the BMS?

I'm in the fortunate position that I'm logging _everything_ about my batteries every minute, so I can see what they are doing and twiddle the code to drill down into what's actually going on (too lazy to put better numbers on the above, but I _could_ if I had to), if you are flying blind you might want to get Solar Assistant and an RS485 interface and hook up some cables and gather some data and see what's actually going on rather than have EG4/SS tell you what worked on Thursday.

This of course is the DIY way, but it starts with Understand It Yourself (with a generous helping of assistance from the clever folks on this forum). UIYdiysf doesn't have the same brand recognition.

 

[txaggie113]

Here I am with my EG4 GB, FB18, and two PP batteries about to be ordered and freaking out about all the 'what ifs' in here!

 

[Zapper77]

Sorry, but IMHO that's a completely broken paradigm. Especially the EG4 WallMounts, the easiest way to reach 100% SOC (and reset the coulomb counter) is (*) to hit 56.5(ish) volts and/or cell voltages of 3.525(ish) volts.

You should never hit COVP, that's an indication that something's seriously wrong, so the BMS shuts off the charge FETs. Unless you've been using the BMS as a charge controller, and have stressed the FETs so much that one or more of them has shorted, and then it _can't_ disconnect, so your battery catches fire instead. So maybe 'battery caches fire' is the tertiary safety disconnect mechanism?

(*) EG4/SS isn't saying, probably because they don't know, but that's about when all mine reset to 100%

Depends on which BMS/Battery.

I left out a few details that aren't public but below is a basic overview.

All of them have a specific Cell OV and/or Pack Voltage that will trigger 0% and 100%, our 3rd Gen BMS has additional logic that uses charging current and voltage.

The original LP4v1 BMS balance works best when it has a small trickle charge.
Our newest 3rd Gen BMS will balance during charge, idle and discharge (when the voltage is above 54v).

As you mentioned above passive balancing 15-280ah cells at 100 ma takes multiple hours.

*We have 14 different BMS (Counting Legacy Server Racks 12/24/48).

 

[wpns]

Depends on which BMS/Battery.

I left out a few details that aren't public but below is a basic overview.

All of them have a specific Cell OV and/or Pack Voltage that will trigger 0% and 100%, our 3rd Gen BMS has additional logic that uses charging current and voltage.

The original LP4v1 BMS balance works best when it has a small trickle charge.
Our newest 3rd Gen BMS will balance during charge, idle and discharge (when the voltage is above 54v).

As you mentioned above passive balancing 15-280ah cells at 100 ma takes multiple hours.

*We have 14 different BMS (Counting Legacy Server Racks 12/24/48).

OK, now we have someone in the know!

Basically that appears to be their solution for any top end imbalance is to set off the over voltage protection and that is supposed to prompt the BMS to begin balancing on future charging.

Does this make sense for ANY of your 14 BMSen?

 

[Zapper77]

OK, now we have someone in the know!

Does this make sense for ANY of your 14 BMSen?

The cell OV will trigger 100% SOC and turn off the charging MOS. I would only recommend that it you wanted to trigger 100% SOC because of SOC drift.

Edit: for balancing: LL v1 4/6 dip, and anything newer the cells will still balance.

The LP4v1 on the newest firmware 3.32 or newer will balance but only when idle or charging. If the battery starts to discharge it will stop balancing.

 

[IAm_Not_Lost]

OK, now we have someone in the know!

Does this make sense for ANY of your 14 BMSen?

The cell OV will trigger 100% SOC and turn off the charging MOS. I would only recommend that it you wanted to trigger 100% SOC because of SOC drift.

Edit: for balancing: LL v1 4/6 dip, and anything newer the cells will still balance.

The LP4v1 on the newest firmware 3.32 or newer will balance but only when idle or charging. If the battery starts to discharge it will stop balancing.

Alright, so, assuming everything EG4 has just had me do is only resetting the SOC calibration, and isn’t going to help my one cell that is much lower than the others during charging, what is my next step?

I’m running open loop, and I use Midnite Classics to charge. I have super limited ability to be home when it’s going to be going into absorb charge just due to my schedule.

Is there a simple tool/software I can utilize to help manage this? Anything straightforward and succinct would be incredibly appreciated.

 

[kampto]

My 280ah EG4 wall mount in SOC mode with 6000xp stops bulk (100%) at ~53v and floats at ~52.6 rest off day. It has never once reached the specified charging specs in SOC mode. EG4 recommended putting in lead acid mode and bulk it to 58v and float at 54v for a week of cycles, didn't help. Had this set up for over a year, when I visit this off grid place I feel like the battery capacity is diminishing over time. Morning voltage seems to be lower now. But no way to remotely monitor all the individual cell voltages at the same time and the app max / min cell voltage makes no sense.

 

[Koyaanisqatsi]

what is my next step?

I’m running open loop, and I use Midnite Classics to charge. I have super limited ability to be home when it’s going to be going into absorb charge just due to my schedule.

Set your float voltage to the same as your absorb voltage and let it go for a few days to a couple weeks like that. You need time on the cell balancer to bring that low one back up. 15 minutes of cell balancing is clearly not enough, and you need to let it run all day to catch up.

You want that low cell back up to around 3.45V if possible - it might take a long time to get there. Once the cell comes back up, try to figure out how long of an absorb stage you need to keep that cell in balance after every charge. Then you can reduce your float voltage back to normal.

 

[fnnwizard]

Alright, so, assuming everything EG4 has just had me do is only resetting the SOC calibration, and isn’t going to help my one cell that is much lower than the others during charging, what is my next step?

I’m running open loop, and I use Midnite Classics to charge. I have super limited ability to be home when it’s going to be going into absorb charge just due to my schedule.

Is there a simple tool/software I can utilize to help manage this? Anything straightforward and succinct would be incredibly appreciated.

You can download the BMS software here:

EG4® WallMount All Weather - EG4 Electronics

Discover the reliable and durable EG4 WallMount All Weather Battery, featuring IP65 outdoor rating, 10kW power delivery, and 8000 cycle life.

eg4electronics.com

Need an adapter like this 4ch "deluxe" one:

Amazon.com: Waveshare Industrial USB to 4Ch RS485 Converter, Multi Protection Circuits, Multi Systems Support, Aluminium Alloy Case, Wall-Mount & Rail-Mount Support : Electronics

Buy Waveshare Industrial USB to 4Ch RS485 Converter, Multi Protection Circuits, Multi Systems Support, Aluminium Alloy Case, Wall-Mount & Rail-Mount Support: Desktop Barebones - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Run it on a computer and use chrome for remote operation.

Base on your info, I don't think you will be able to get this pack in balance since I think your low cell is likely somewhere around a 28Ahr deficit.

Here's why:
If spec sheet is accurate, the bms balancing is 120mA at 3.2V (calcs out to 27 Ohm resistor) so at say 3.5V, it'll balance at 131mA. 28,000mAh / 131mA= >213 hrs or 9 straight days of continuous balancing/micro charging, holding at least 1 cell initially for all that time (and eventually all 15 cells at 3.5V), to me that's severe overcharging.

IOW, you'll be charging the low cell at 131mA. Any faster and tgt V will be reached and charging stops, though the discharge resistors keep working so the charging incrementally stays on a wee-bit longer each time.. emphasize "wee-bit", lol... if you are able to charge at this rate, the balancing resistors are basically absorbing the pwr to the hi cells.

My 280ah EG4 wall mount in SOC mode with 6000xp stops bulk (100%) at ~53v and floats at ~52.6 rest off day. It has never once reached the specified charging specs in SOC mode. EG4 recommended putting in lead acid mode and bulk it to 58v and float at 54v for a week of cycles, didn't help. Had this set up for over a year, when I visit this off grid place I feel like the battery capacity is diminishing over time. Morning voltage seems to be lower now. But no way to remotely monitor all the individual cell voltages at the same time and the app max / min cell voltage makes no sense.

This is exactly what will happen if the charging V is st too high. There is no chance for the cells to balance. The delta increases with each cycle. your hi and lo cells starts to see more "1 way action" where the hi cell keeps hitting the highs and the lows keep hitting lows vs other cells leading to lopsided degradation.

Best is to take cover off and individually charge lo and at the same time dischg hi.

There's really nothing else we can do once it gets to that point if we want to use most of the capacity.

If taking cover off is 100% no go and no other recourse, set bulk to lowest pack V that drives the highest cell to 3.55V (there's a reason why I use 3.55V vs all others, but that's a longer discussion) with float that drives highest cell to 3.475 and use batts for 1-2 years and it should balance out if batts hit bulk V each/everyday.


@Zapper77 :
Edit to add... when we have large imbalances , hitting 100% soc means nothing... who cares about soc at this point.

For Eg4/LuxP AIOs, running under soc, they hard code in a do not run <10%. If yoour bats hit this level, it goes to ac charge (if GT) and nothing will stop it outside of shutting it down until it gets to 13% where it goes to standby, waiting on PV. All the while, loads are being fed from grid and you won't be able to use batts until they get up to 15% soc.. God forbid you are on one of those plans where it's >$.75/kWh when this happens .

So if you have a say 10% imbalance, when soc resets to 100, your bms thinks you have 280Ahr capacity when you really have onl 250Ah. So guess what happens at 20%.. yep, soc goes off a cliff to 10%, but maybe worst a cell goes UVP.

 

[wpns]

For Eg4/LuxP AIOs, running under soc, they hard code in a do not run <10%.

Wow, good thing they don’t do that in offgrid mode, my CVs are powered up at 10% and dip down to 9 or 8 by the time they ramp up.

 

[wpns]

The cell OV will trigger 100% SOC and turn off the charging MOS. I would only recommend that it you wanted to trigger 100% SOC because of SOC drift.

Edit: for balancing: LL v1 4/6 dip, and anything newer the cells will still balance.

The LP4v1 on the newest firmware 3.32 or newer will balance but only when idle or charging. If the battery starts to discharge it will stop balancing.

You didn’t answer the question:

Basically that appears to be their solution for any top end imbalance is to set off the over voltage protection and that is supposed to prompt the BMS to begin balancing on future charging.

Does this make sense for ANY of your 14 BMSen?

 

[fnnwizard]

Wow, good thing they don’t do that in offgrid mode, my CVs are powered up at 10% and dip down to 9 or 8 by the time they ramp up.

This was actually in off grid mode, with grid connection. The true SOC was >30%ish, but displayed avg soc dropped to 9% so the 18kpv switch to ac charging at 500W total. 60kWh capacity, so about 5hrs later it reach 13% and went on standby. In the morning PV got it up to 15% before discharging can take place.

Spoke to LuxP tech and they didn't know about this "safety feature". Just happend of course during highest rates for me, lol.

As you know, I AC charge at 100W during winter nights just to keep batts in stndby when not enough PV to carry through high TOU rates. This of course "phantom" charges banks and can give big undereported SOC .

I've since found another work around to keep 18 from selling back but havent tested it for long enough to be 100% confident and that is to set AC charge V to something like 50V within the ac charge window. It effectively then just uses grid for loads and batts stay in standby so far for the few hiurs I tested it.

Won't be able tothoroughly test until winter again since summer have plenty PV. oh, firmware 2021

 

[Zapper77]

My 280ah EG4 wall mount in SOC mode with 6000xp stops bulk (100%) at ~53v and floats at ~52.6 rest off day. It has never once reached the specified charging specs in SOC mode. EG4 recommended putting in lead acid mode and bulk it to 58v and float at 54v for a week of cycles, didn't help. Had this set up for over a year, when I visit this off grid place I feel like the battery capacity is diminishing over time. Morning voltage seems to be lower now. But no way to remotely monitor all the individual cell voltages at the same time and the app max / min cell voltage makes no sense.

A location with very little load or no load for weeks, I'd recommend just using Volt and not SOC.

 

[kampto]

A location with very little load or no load for weeks, I'd recommend just using Volt and not SOC.

Yeah, 150 to 300w load for weeks. Then when I get there for 4 days a month it steps up Loads with Fridge and occasional 20min hit with well pump.

 

[wpns]

You didn’t answer the question:

Does this make sense for ANY of your 14 BMSen?

@Zapper77 I know it's easy to lose track of queries, but this one is fairly important, can you answer the question?