Top charging the EG4-WallMount Indoor Battery

[opticalcarrier]

I have 3 of these "EG4-WallMount Indoor Battery | 48V 280Ah | 14.3kWh | Indoor | Heated UL1973, UL9540A | 10-Year Warranty" and can someone tell me how much current we should expect these to start dropping off for them as SOC approaches 100%?

When I first got my 3 of these and started to top charge them for a good starting balance, each individually one at a time, from the solark12k inverter, then it got to 99% and the solark was still delivering max current. I seem to recall that as these batteries reach 100% SOC the current flow should start to tail off... Am I recalling that wrong?

I just want to make 100% sure here that the BMSs in these things do things correctly. Is there an internal breaker that the BMS will trip during an overvoltage or too-high-current situation?

Edited to add:
Im doing closed loop (CAN) from the solark to the 1st batt, with all the others daisy chained as per manual, all 3 set for the solark can protocol, for their closed loop comms. Th other 2 batteries' power leads both connect directly to the #1 battery which is addressed as #1, then the others are addressed as #2 and #3. And I *guess* things are good there? Cant really tell for sure on the batteries, if I do disconnect the CAN from the solark, the batteries dont show a thing on their displays, but the solark does show a triangle with a ! in it when I disconnect that CAN cable, and it goes away when I reconnect it.
Id really like to better know whats going on there, since like I said when I was doing the initial top balance, when a battery connected all on its own and addressed as #1 to the solark got to 99% it was still pulling tons of current, which I though was strange, so I watched it like a hawk and as soon as I saw it change to 100% I flippped the DC battery breaker I added right at the solark's battery terminals.

 

[wpns]

Are you doing closed-loop comms between the inverter and the batteries?

If not, what do you have the inverter’s charge settings configured to?

 

[opticalcarrier]

I have 3 of these "EG4-WallMount Indoor Battery | 48V 280Ah | 14.3kWh | Indoor | Heated UL1973, UL9540A | 10-Year Warranty" and can someone tell me how much current we should expect these to start dropping off for them as SOC approaches 100%?

When I first got my 3 of these and started to top charge them for a good starting balance, each individually one at a time, from the solark12k inverter, then it got to 99% and the solark was still delivering max current. I seem to recall that as these batteries reach 100% SOC the current flow should start to tail off... Am I recalling that wrong?

I just want to make 100% sure here that the BMSs in these things do things correctly. Is there an internal breaker that the BMS will trip during an overvoltage or too-high-current situation?

Edited to add:
Im doing closed loop (CAN) from the solark to the 1st batt, with all the others daisy chained as per manual, all 3 set for the solark can protocol, for their closed loop comms. Th other 2 batteries' power leads both connect directly to the #1 battery which is addressed as #1, then the others are addressed as #2 and #3. And I *guess* things are good there? Cant really tell for sure on the batteries, if I do disconnect the CAN from the solark, the batteries dont show a thing on their displays, but the solark does show a triangle with a ! in it when I disconnect that CAN cable, and it goes away when I reconnect it.
Id really like to better know whats going on there, since like I said when I was doing the initial top balance, when a battery connected all on its own and addressed as #1 to the solark got to 99% it was still pulling tons of current, which I though was strange, so I watched it like a hawk and as soon as I saw it change to 100% I flippped the DC battery breaker I added right at the solark's battery terminals.

Im doing closed loop (CAN) from the solark to the 1st batt, with all the others daisy chained as per manual, all 3 set for the solark can protocol, for their closed loop comms. Th other 2 batteries' power leads both connect directly to the #1 battery which is addressed as #1, then the others are addressed as #2 and #3. And I *guess* things are good there? Cant really tell for sure on the batteries, if I do disconnect the CAN from the solark, the batteries dont show a thing on their displays, but the solark does show a triangle with a ! in it when I disconnect that CAN cable, and it goes away when I reconnect it.
Id really like to better know whats going on there, since like I said when I was doing the initial top balance, when a battery connected all on its own and addressed as #1 to the solark got to 99% it was still pulling tons of current, which I though was strange, so I watched it like a hawk and as soon as I saw it change to 100% I flippped the DC battery breaker I added right at the solark's battery terminals.

 

[wpns]

That's weird, the display on the battery doesn't wake up when you tap the screen or press a button? I've only ever done closed loop with 18Kpv on the Outdoor battery, but I just let it do its thing.

I wouldn't panic about continuing to charge after it hits '100%', mine don't taper off, but go from 'charging as much as the input PV allows' to 'bouncing between charge/discharge to cover the load'.

 

[LilMt]

Based on my own very limited experience, it appears that the current into these batteries stays mighty high all the way through the charge cycle.

Also, according to the spec sheets, the BMS's do have protection.




One thing I noticed was that it took a few cycles to get the BMS's and the inverter to get everything "figured out". Mine would show 100 % on the inverter but the battery would show 99%. One battery was always charging/discharging slightly faster than the other. After 3 days of cycles, it leveled out. Also, for the first few cycles, the inverter would show the batteries as 100%SOC but keep charging for 10 to 15 minutes. This too seems to have cleared up after a few cycles.

This has been my experience, but I would sure like to see a set of charge/discharge graphs for these batteries.

Hope this helps some,

LilMT

 

[opticalcarrier]

Well - the batteries screens DO come alive and I see some stats on current flow, but nothing affirming a solid CAN connection, lack thereof, status of overprotection, etc etc etc.

So what happens then when the overprotection kicks in? How would I even know it kicked in (given the seemingly minimal info available on the screen)?

OK then I guess the guidance here is go back to 1 battery at a time, and let the solark just give a battery as much current until "something" happens???? Stop again as soon as I see 100%? Or something else? Theres just a lack of instruction here on how we know its "good".

I just really really REALLY dont want to burn my house down. Thanks all

 

[LilMt]

If the protection kicks in you should get an alarm state on the battery. Red light above the green light.

With the over voltage at the cell level the BMS would stop charging until that cell volage comes back into range. Not certain what over current would do. Either trip the battery breaker or the BMS would shutdown.

This manual explains what is protected, not necessarily the process of protection though:

https://eg4electronics.com/wp-content/uploads/2024/04/EG4%C2%AE-Indoor-280Ah-Battery-Troubleshooting-Maintenance-Guide.pdf

Good luck and please keep us posted.

LilMT

 

[wpns]

This has been my experience, but I would sure like to see a set of charge/discharge graphs for these batteries.

Yeah, the major downside is the inability to see individual battery (and cell) stats, though there may be some optimizations there...

 

[wpns]

Well - the batteries screens DO come alive and I see some stats on current flow, but nothing affirming a solid CAN connection, lack thereof, status of overprotection, etc etc etc.

The controls should allow you to see the individual cell voltages.

 

[opticalcarrier]

If the protection kicks in you should get an alarm state on the battery. Red light above the green light.

With the over voltage at the cell level the BMS would stop charging until that cell volage comes back into range. Not certain what over current would do. Either trip the battery breaker or the BMS would shutdown.

This manual explains what is protected, not necessarily the process of protection though:

https://eg4electronics.com/wp-content/uploads/2024/04/EG4%C2%AE-Indoor-280Ah-Battery-Troubleshooting-Maintenance-Guide.pdf

Good luck and please keep us posted.

LilMT

OK revered to just 1 and see how well it does this time Ill leave it until it gets to 100% AND I see the BMS has halted things. Then will do the other 2 just like that then assemble it all back.

I'd really like to get a good view into status and performance though, so Im seriously considering dumping CAN and letting the solark do things with float/voltage/etc style. In that case can I get a generic RS485-to-USB adapter and use that with all 3 batteries here on my PC? Or would I need to get 3 adapters, one for each battery?

 

[opticalcarrier]

One thing I noticed was that it took a few cycles to get the BMS's and the inverter to get everything "figured out". Mine would show 100 % on the inverter but the battery would show 99%. One battery was always charging/discharging slightly faster than the other. After 3 days of cycles, it leveled out. Also, for the first few cycles, the inverter would show the batteries as 100%SOC but keep charging for 10 to 15 minutes. This too seems to have cleared up after a few cycles.


LilMT

I have been wondering specifically about this as well... Do you use CAN or RS485 or the regular voltage sensing on the inverter?

My question here is in regards to my use of can... where what happens when the "main" battery is at 100% and doesnt want to charge any more but hte other batteries are at like 98%? Would that main battery's BMS allow the other 2 to charge?

Or the other way, what if 2 of the "slave" batteries are both at 100% and dont want to recieve any more current, but the "main" battery with the CAN connection to the inverter is at 97% and wants more current? Would a CAN setup allow this to happen?

Or mayber I guess the bonus of not doing it CAN-style then is that each batteries BMS can activate and work separately from the others?

 

[LilMt]

I have been wondering specifically about this as well... Do you use CAN or RS485 or the regular voltage sensing on the inverter?

My question here is in regards to my use of can... where what happens when the "main" battery is at 100% and doesnt want to charge any more but hte other batteries are at like 98%? Would that main battery's BMS allow the other 2 to charge?

Or the other way, what if 2 of the "slave" batteries are both at 100% and dont want to recieve any more current, but the "main" battery with the CAN connection to the inverter is at 97% and wants more current? Would a CAN setup allow this to happen?

Or mayber I guess the bonus of not doing it CAN-style then is that each batteries BMS can activate and work separately from the others?

I have a 6000xp and I use CAN.
From what I can tell by watching the batteries on the monitoring site. I appear that when one battery (doesn't matter slave or master) get full, it then stops charging and the other battery(ies) continue charging.

I think there is some logic in them that self-monitor their charging and make slight adjustments as needed (over rime). I am not sure about that as I am not a BMS guy. Spent too many years with lead acid and just watch my voltages.

From what I can tell, even with CAN the BMS's appear to work independently but the coms between them aids in safety and in efficiency. (I am not certain of that though and is purely a wild guess) Someday I will need to sit down and get my head wrapped around the BMS technology a little (a lot) more.

Thanks,
LilMt

PS, here is a snip of my current battery parameters showing that one battery is getting 5A while the other is getting 4.5. I am guessing that that is being controlled by the BMS

If I remember I will try to check it when one is at %100 and the other is at 99% and see what the amp difference is then.

 

[LilMt]

Here is the image with the inverter saying the batteries are at 99%
You can see one battery is 100% but still drawing 1 amp. I am assuming this is cell balancing.
The other battery is still charging at 7.3 amp.

My guess is that this is the BMS's doing their job.

The lower input in because of poor sun today. Lots of intermittent clouds.


Here the cell balancing appears to be done on the master battery and in a few minutes the cell balance should be done on the slave battery.

Don't know if this helps any but it's fun to watch.

Thanks,
LilMt

 

[opticalcarrier]

im starting to think that this 1 battery unit I got has a bad cell in it, or something else wrong with it... The pack was showing 90% soc and when I put it by itself on the inverter and it started taking current it *very* quickly got to 100% and then went to standby.

Contrast that to this 2nd one that was at 98% when I put it on the inverter by itself, and it took a bit longer to get to 100% and was charging at about 1KW for about an hour before it went to standby. The 3rd did the same as the second.

And then, I readdressed the #2 and #3 and chained them up and connected the power leads, turned their breakers and BMSs on, but had left the batter breaker on the inverter off, and then #1 started reporting discharge and 2 and 3 reported charging. eventually both went to standby with 55.14v on #1 and 55.17v on #2 and 55.16v on #3.

I then cut on the inverters battery breaker and the batteries started kicking in and delivering power, 55amp for #1 and 45 for #2 and #3, which I also thought was odd, also leading me to believe that again here now I will see #1 reach 15% SOC well before the others. Not sure what to do, is all this really a problem?

 

[LilMt]

Looks as if Cell Balancing is complete:

and the BMS is now disallowing charging to the batteries:

As I mentioned this is ALL conjecture on my part. Take it with a grain of salt unless one of the BMS guru's chime in to confirm or deny.

Good luck and have a great day,
LilMt

 

[LilMt]

im starting to think that this 1 battery unit I got has a bad cell in it, or something else wrong with it... The pack was showing 90% soc and when I put it by itself on the inverter and it started taking current it *very* quickly got to 100% and then went to standby.

Contrast that to this 2nd one that was at 98% when I put it on the inverter by itself, and it took a bit longer to get to 100% and was charging at about 1KW for about an hour before it went to standby. The 3rd did the same as the second.

And then, I readdressed the #2 and #3 and chained them up and connected the power leads, turned their breakers and BMSs on, but had left the batter breaker on the inverter off, and then #1 started reporting discharge and 2 and 3 reported charging. eventually both went to standby with 55.14v on #1 and 55.17v on #2 and 55.16v on #3.

I then cut on the inverters battery breaker and the batteries started kicking in and delivering power, 55amp for #1 and 45 for #2 and #3, which I also thought was odd, also leading me to believe that again here now I will see #1 reach 15% SOC well before the others. Not sure what to do, is all this really a problem?

I would suggest opening a ticket with your reseller.

To my little brain that 10amp differential seems a fairly big divergence but it would probably be best to ge a professional answer.

Perhaps an EG4 tech will chime in.

 

[LilMt]

On the front screen of the battery, you can go to settings and then I think voltage. If I remember right this will show you some of the per cell information. I cannot remember what all it shows, or if that is even the correct way to get there. But it might be worth taking a peek.

 

[opticalcarrier]

OK Ill go look in there to see what there differences are of the cells in high SOC state versus low SOC state.

Regarding a switch to non-closed loop though, Im considering this if it will allow me to use the rs485 bus on my PC with BMS tools... will this setup allow to manage all 3 batteries at once, or would I manually have to change the connector to different batteries?

 

[wpns]

OK Ill go look in there to see what there differences are of the cells in high SOC state versus low SOC state.

Regarding a switch to non-closed loop though, Im considering this if it will allow me to use the rs485 bus on my PC with BMS tools... will this setup allow to manage all 3 batteries at once, or would I manually have to change the connector to different batteries?

Sounds like a backwards step to go open-loop, then you need to decide what output voltage the SCC should apply based on the SOC of all of the batteries.

Not sure if you could put all the battery comms in parallel or if you'd need a separate interface for each battery. Hopefully the former...

 

[LilMt]

OK Ill go look in there to see what there differences are of the cells in high SOC state versus low SOC state.

Regarding a switch to non-closed loop though, Im considering this if it will allow me to use the rs485 bus on my PC with BMS tools... will this setup allow to manage all 3 batteries at once, or would I manually have to change the connector to different batteries?

I am not certain, but from what little I have read on the subject, I think it is one battery at a time as I believe you need to set the battery ID to 64 for BMS Tools to talk to the battery not certain at all though.