Understanding 4 6500ex comm options to diff load centers, SA too.

If I setup one set of 2x6500ex in 240 split phase with AC OUT HOTS feeding one load center, AND another set of 2x6500ex in 240 split phase again with AC OUT HOTS feeding different load centers (two this time), my understanding is I do NOT need to connect the current sharing cable in this configuration. AND the serial comm cables can be connected like if it were only 2x6500ex 240 split phase, done on each set…correct?

For the 6x lifepower4 batts, in this way though I would NOT have a master inverter, if set to eg4 for the batt comm, run the batt charging for all FOUR inverters. I would have to config a set of inverters manually for the batt charging…correct?

RE, solar assistant, I would have to connect another usb to rj45 for sa to report on the other inverter set…correct?

So I can do it this way, or simply connect the four up like how the manual says but they would just go to their separate load centers and have the current sharing cable connect, etc.

Just want to confirm I have all this correct and am not missing a problem somewhere. Can someone confirm or correct? Thanks.

If the load centers are completely isolated from each other, then it would be just like you're setting up two separate systems and you would not connect inverter pair 1 to inverter pair 2 at all.

You can share the batteries between the pairs and you "might" be able to set one pair to EG4/Use but the other pair would have to be set to Use/Use. I would probably just set them all to USE.

From the Solar Assistant standpoint, in theory yes you would need another cable from your second pair to go to SA. Since all the inverters are the same, it seems like it should work. Never heard anyone doing it with different load centers before but I don't see how the output should change the configuration at all.

Adam De Lay said:

If the load centers are completely isolated from each other,

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Only the hots…the neutrals are common and grounds are shared…but I think that’s what you meant. Just want to double check myself.

jfharper said:

Only the hots…the neutrals are common and grounds are shared…but I think that’s what you meant. Just want to double check myself.

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Can't say I've ever heard of anyone wiring things up like that. I know the grounds should be fine because you're supposed to connect everything to the main ground rod anyways. I'm no electrician but I would think the N should be fine because it's really no difference if you had all 4 wired together. You would just want all the inverters option 42 set to ENA to enable the common neutral in each inverter.

They are two separate systems. The only thing that they should have in common is the AC input source and the batteries.
No parallel cables between the two systems. (Comms or current sharing)

PS: Solar Assistant can monitor all as one.

Adam De Lay said:

If the load centers are completely isolated from each other, then it would be just like you're setting up two separate systems and you would not connect inverter pair 1 to inverter pair 2 at all.

You can share the batteries between the pairs and you "might" be able to set one pair to EG4/Use but the other pair would have to be set to Use/Use. I would probably just set them all to USE.

From the Solar Assistant standpoint, in theory yes you would need another cable from your second pair to go to SA. Since all the inverters are the same, it seems like it should work. Never heard anyone doing it with different load centers before but I don't see how the output should change the configuration at all.

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Can you recommend a starting point for the settings for if I set them all to USE. I’m totally lost on that at the moment. Don’t want to damage anything. Trying to understand that manual is very challenging.

This is why I thought it might be easier to go eg4/use have the bms do it for me and comm connect the entire system somehow.

jfharper said:

Can you recommend a starting point for the settings for if I set them all to USE. I’m totally lost on that at the moment. Don’t want to damage anything. Trying to understand that manual is very challenging.

This is why I thought it might be easier to go eg4/use have the bms do it for me and comm connect the entire system somehow.

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You might have to look at the specs on the Lifepower batteries to see if there’s recommendations there. From what I’ve seen, each person has their own “sweet spot” that they have found where they like to have their batteries charge to.

Adam De Lay said:

You might have to look at the specs on the Lifepower batteries to see if there’s recommendations there. From what I’ve seen, each person has their own “sweet spot” that they have found where they like to have their batteries charge to.

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Yeah, it’s a new area of this build I need to devote some time in learning. Many have built their own banks and bms and have that knowledge. Whereas I arrived later in the game and choose to go a little more turn key, but I lack in the battery/bms area.

Yesterday, I got all 4 inverters going with the entire setup. I went USE on all the battery settings and thought I should disconnect the batt comm cable figuring the inverter might throw a batt comm error. Everything seemed to work, except the battery rack seemed to get confused with the soc or something. Before I turned everything on, the rack was at like 78% so three lights on and fourth would flash indicating charging in the 76-100 range. This was with two inverters on, eg4 set for setting 5 and batt comm connected. When I powered everything down to install the new bus bars, I configured USE on all four inverters, turned it all on and the rack showed two green lights soc with the third blinking. I thought maybe USE setting lowered some threasholds or something causing the soc on the lifepower4s to report lower than when set to eg4 on a master inverter. It all worked, I mean I got no errors and the output volts were correct. SA showed no battery because of no cable, but I got nervous and thought I’d try your suggestion of eg4 on one set of inverters and USE on the other set because I don’t have any pv setup yet for the other two inverters…I still need to build that ground mount and panels. So the other two inverters are only going to run from the batteries for the time being. That all worked and I reconnected the batt comm cable so I could at least watch the battery bank in SA. The soc lights went back to the 78% and it all worked as expected. I need another cable from Amazon so I can plug the other master inverter into SA to see the loads, which I’m assuming will work.

I figured the bulk of the user defined battery settings on the 6500exs I don’t quite understand yet relate to the charging on the batteries. I understand the settings that relate to when the inverter will turn off if the batteries are too low, or would switch back and forth from utility, which don’t apply to me since no AC IN is connected, but the other settings are custom sweet spot like you said and require a bit of study.

This was why I asked in my original question that started this thread about setting the inverters up like in the manual with comm cables all connected so I could set one up with the eg4 setting, and I think the other three would be USE or something. I figured that might easier for me now until I get a chance to learn more about the batteries. But @timselectric recommended I keep the two systems separate, so I’m starting with that until I learn more and feel more confident about doing something else.

There’s also the question in my mind about why SS offered an extended warranty on the 6500ex if they were paired with lifepower4 batteries. Is it because we are to keep them set to eg4 on the master? Haven’t figured that one out yet.

The charger will charge the batteries up to the set bulk voltage. Once that is reached, the charger will fall back to the set float voltage. And hold the batteries at that float voltage until the sun goes down. Or it times out, if it's programed to timeout.

Batteries are usually at around 50% SOC when received. They should be fully charged before placing into service. Using the BMS_Tools software you can ensure that the cells in each battery get to balancing which will reset the BMS SOC to a true SOC.

You can also ensure all batteries have the same firmware. The latest firmware can be downloaded from the EG4 website and installed using the BMS_Tool software.

You might find investing in a Victron shunt and EG4 Charge-Inverter a worthwhile investment.

The EG4 Lifepower4 batteries have two RJ45 jacks that are connected in parallel with pins 1&2 as one RS485 bus (normally used for battery to inverter or battery to monitoring software; i.e. SA or the BMS_Tool) and pins 7&8 are a second RS458 bus used for battery to battery communications.

SA or the BMS_Tool software can monitor all batteries and display them if connected to the battery RJ45 port (using and RS485 to USB Converter) but only if you do not have the batteries (master) connected to the inverter. The battery to inverter uses the same pins 1&2.

The only way to monitor the batteries in closed loop is by use of the EG4 Communications Hub between the batteries and the inverter.

Not sure that SA can monitor more than one inverter (or pair of paralleled inverters) as it only has one invert configuration (or at least mine only has one). You may need a second SA to monitor both inverters where one can monitor an inverter and the batteries and the other an inverter and the shunt if you install one.

So I have a dumb question at this point - with two sets of parallel inverters that are only connected at the battery how will things react when both inverter pair decides to charge at the same time. Since each of these inverters has a max charge current of 120amps will they all put out a total of 480amps? I would assume in the normal setup you would have all 4 inverters running one set of AC loads and all connected together with the RS485 bus and to the batteries to determine the optimal charge current?

But, if I understand the advice given so far the two pairs will only be connected at the bus bars to the batteries and no communications between them. That would seem to be a hole in the logic and none of the inverters in total control of the charging?

robbob2112 said:

So I have a dumb question at this point - with two sets of parallel inverters that are only connected at the battery how will things react when both inverter pair decides to charge at the same time. Since each of these inverters has a max charge current of 120amps will they all put out a total of 480amps? I would assume in the normal setup you would have all 4 inverters running one set of AC loads and all connected together with the RS485 bus and to the batteries to determine the optimal charge current?

But, if I understand the advice given so far the two pairs will only be connected at the bus bars to the batteries and no communications between them. That would seem to be a hole in the logic and none of the inverters in total control of the charging?

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With open loop, the charging is done according to your settings.
There is no problem with multiple charging sources. As long as the total charging doesn't exceed the battery manufacturers recommendations.
This way the BMS (battery management system) is only in charge of managing the battery.
This is always my preference and recommendation.

Why? Because simple is reliable.
Every day there are several new threads about trouble with closed loop communications.
And zero threads about trouble with open loop.

robbob2112 said:

So I have a dumb question at this point - with two sets of parallel inverters that are only connected at the battery how will things react when both inverter pair decides to charge at the same time. Since each of these inverters has a max charge current of 120amps will they all put out a total of 480amps? I would assume in the normal setup you would have all 4 inverters running one set of AC loads and all connected together with the RS485 bus and to the batteries to determine the optimal charge current?

But, if I understand the advice given so far the two pairs will only be connected at the bus bars to the batteries and no communications between them. That would seem to be a hole in the logic and none of the inverters in total control of the charging?

Click to expand...

timselectric said:

With open loop, the charging is done according to your settings.
There is no problem with multiple charging sources. As long as the total charging doesn't exceed the battery manufacturers recommendations.
This way the BMS (battery management system) is only in charge of managing the battery.
This is always my preference and recommendation.

Why? Because simple is reliable.
Every day there are several new threads about trouble with closed loop communications.
And zero threads about trouble with open loop.

Click to expand...

I'm glad this was asked and explained because, as you probably guessed, it was mulling in my mind. I assume closed loop = all 4 inverters comm connected paralllel/current/etc and open loop = what I have.

marionw said:

Batteries are usually at around 50% SOC when received. They should be fully charged before placing into service. Using the BMS_Tools software you can ensure that the cells in each battery get to balancing which will reset the BMS SOC to a true SOC.

You can also ensure all batteries have the same firmware. The latest firmware can be downloaded from the EG4 website and installed using the BMS_Tool software.

You might find investing in a Victron shunt and EG4 Charge-Inverter a worthwhile investment.

The EG4 Lifepower4 batteries have two RJ45 jacks that are connected in parallel with pins 1&2 as one RS485 bus (normally used for battery to inverter or battery to monitoring software; i.e. SA or the BMS_Tool) and pins 7&8 are a second RS458 bus used for battery to battery communications.

SA or the BMS_Tool software can monitor all batteries and display them if connected to the battery RJ45 port (using and RS485 to USB Converter) but only if you do not have the batteries (master) connected to the inverter. The battery to inverter uses the same pins 1&2.

The only way to monitor the batteries in closed loop is by use of the EG4 Communications Hub between the batteries and the inverter.

Not sure that SA can monitor more than one inverter (or pair of paralleled inverters) as it only has one invert configuration (or at least mine only has one). You may need a second SA to monitor both inverters where one can monitor an inverter and the batteries and the other an inverter and the shunt if you install one.

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This thread: https://diysolarforum.com/threads/solar-assistant-power-backfeed-from-eg4.69755/
@solarhombre generously shared their M5stack setup for battery monitoring. I've purchased the components but haven't had time to set things up...I thought that was pretty cool.

@timselectric mentioned I should be able to get SA to see all the inverters as one somehow...that's on my list of things to figure out. I have a second usb to rj45 cable (really I'm going from USB to serial rs232, thru an rs232 isolator to help protect the inverter, then rs232 to the rj45 jack on the inverter) on it's way from amazon, I was just going to plug it into SA and my second set of inverters to see if SA would report all, if not, ?

jfharper said:

@timselectric mentioned I should be able to get SA to see all the inverters as one somehow...that's on my list of things to figure out. I have a second usb to rj45 cable (really I'm going from USB to serial rs232, thru an rs232 isolator to help protect the inverter, then rs232 to the rj45 jack on the inverter) on it's way from amazon, I was just going to plug it into SA and my second set of inverters to see if SA would report all, if not, ?

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Solar Assistant can only connect to a single inverter "type/manufacturer" at a time. Since all 4 of yours are the same, they all should just show as a unified system in SA as long as you connect them to SA and select them under the Configuration Tab -> Inverters list.

jfharper said:

I assume closed loop = all 4 inverters comm connected paralllel/current/etc and open loop = what I have.

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Communications between inverters is done as needed for parallel/series operation.
When we talk about open loop or closed loop communications. We are talking about communications between batteries and chargers.
Closed loop = with communications
Open loop = no communications