EG4 18kPV Q+A general thread

Adeon said:

Does anyone know why it’s not discharging.

This seems to happen when ever the batteries hit 100%

Edit: I had to go flick my breaker off that’s powering the 18k to make it discharge. Anyone have any advice?

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You don't need force discharge enabled.

Your settings are conflicting.

Where are your CTs installed?

I’ll check my CTs that might be throwing it off. Will report back once it’s at 100 again.

I have just got everything hooked up 2 days ago.. CT is installed and reporting correctly, and I have a LifePo4 battery with JK BMS hooked up.
I have not figure out how to get JK BMS to talk RS485 with inverter yet, so I am using Voltage to control charge / discharge.

I can see the battery discharge when I have relatively low load ( 2kw ), but whenever I have my heat pump kick in, EG4 switch back to use grid and started charging the battery. I have got a 300Ah battery and configured my discharge current to be 200A, which should be totally enough for this load..

Is there some other setting I need to configure for EG4 to allow battery to discharge at higher current? What am I missing?

I should have asked this question before ordering an 18Kpv and three batteries. Can anyone report success installing feeder taps in a combination meter and main panel? I have Siemens MC series PV-ready panel, and while is does have cables between the meter and main breaker, and so far every electrician has passed on the job without even opening the panel(most saying too busy for a small job, one saying they just did not want the job).

The PV backfeed breaker at the top is connected to a SolarEdge that I plan to AC couple, so one possibility, if it would be code compliant, is to use it as my grid connection, knowing it is limited to 60A and replace the current main breaker with a 100A backfeed connected to the EG4 load side.

I'd rather not replace the meter/panel combo, but if that is what it will take...

New workings modes is released here is the document

I'm a solar rookie (but a highly experienced electrical engineer). I've designed (not installed) a system for my parents home in Sarasota, FL based on the EG4 18KPV unit and would like to tap into the combined experience and wisdom of the group to review it for function and regulatory issues. Is this an appropriate place to post a detailed description of the system and get feedback on it? Or should I make its own thread here or in the beginner's section?

Edit: I posted in the beginner's forum:

Dan_Austin said:

I should have asked this question before ordering an 18Kpv and three batteries. Can anyone report success installing feeder taps in a combination meter and main panel? I have Siemens MC series PV-ready panel, and while is does have cables between the meter and main breaker, and so far every electrician has passed on the job without even opening the panel(most saying too busy for a small job, one saying they just did not want the job).

The PV backfeed breaker at the top is connected to a SolarEdge that I plan to AC couple, so one possibility, if it would be code compliant, is to use it as my grid connection, knowing it is limited to 60A and replace the current main breaker with a 100A backfeed connected to the EG4 load side.

I'd rather not replace the meter/panel combo, but if that is what it will take...

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From what I read, this type of breaker box can't really do whole home backup easily.

If you look at the diagrams, both the feeder side and the supply side whole home backup requires a manual transfer switch between the supply tap point and the main breaker on the main load breaker ( between the meter on the left to your 200A breaker on the right ) Since it will be definitely against code if you alter the panel box, you won't be able to do whole home backup this way .

I think you mean partial home backup with supply side tap? that would work in your current setup. But that would require a sub panel ( which it looks like you do have some beefy wires leading to one )
If possible setup the sub panel as the critical load panel, install 18kv before the subpanel, and connect 18kv's grid to the supply side tap. move circuit you want to backup to connect to that sub panel, and eg4 will then be able to provide backup power to that critical panel when grid is down.

Also you might want to verify if your supply side tap wire is rated for 100AMP.. Is this the exact panel you are using?
If yes then it should be 2AWG wire already, and 100A supply side tap breaker can be installed.
If not, find out what awg those two straight thwn wire on the top side of box is. Your supply side tap breaker size can not exceed those two wire's rating

Thanks for the reply! That is the exact panel, and I do have a sub-panel, but it is on a separate building, so no joy there. The line diagrams are helpful, but is is not clear what parts are optional and which are required, they all include a generator, but that is clearly not required. If the manual transfer switch is recommended but not required, I would hope something like this would be possible and meet code-
Meter -> 100A Breaker on the PV supply lines in the panel -> 2 Pole fused 200A disconnect -> EG4 -> Breaker in loads panel. The original main breaker would be removed as well as the original feed lines from it to the meter.

mciholas said:

I'm a solar rookie (but a highly experienced electrical engineer). I've designed (not installed) a system for my parents home in Sarasota, FL based on the EG4 18KPV unit and would like to tap into the combined experience and wisdom of the group to review it for function and regulatory issues. Is this an appropriate place to post a detailed description of the system and get feedback on it? Or should I make its own thread here or in the beginner's section?

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You could post it in the beginner's section. Then come back and edit your message with a link to it, so we can find it.

Dan_Austin said:

Thanks for the reply! That is the exact panel, and I do have a sub-panel, but it is on a separate building, so no joy there. The line diagrams are helpful, but is is not clear what parts are optional and which are required, they all include a generator, but that is clearly not required. If the manual transfer switch is recommended but not required, I would hope something like this would be possible and meet code-
Meter -> 100A Breaker on the PV supply lines in the panel -> 2 Pole fused 200A disconnect -> EG4 -> Breaker in loads panel. The original main breaker would be removed as well as the original feed lines from it to the meter.

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Firstly.. the setup you mentioned will limit your grid current draw to the supply side tap wire size - which is 100A. So you are essentially downsizing your grid connection to 100A. That 200A fuse will be useless since the current will never go over 200A, the breaker will trip or wire will burn before the fuse will break. Are you certain your 100A breaker won't trip when your battery ran out at night? I don't think this setup could work. upsizing that wire to 2/0 is also not an option - that is altering the panel and will fail inspection immediately. Removing your 200A main breaker as well, since that is also modifying your panel box and will equally fail inspection.

Plus, in this setup, each time you wish to service EG4, you will need to cut the power to the main panel. The whole reason why manual transfer switch is placed in these diagram, is to allow you to easily stop power going to eg4 without interrupting the main panel's service. You can't have a complex inverter that can fail due to software reason sitting in the circuit as a single point of failure in the critical path.

It is true that there is an alternative to manual transfer switch - adding another breaker that can be interlocked to the main breaker. This is similar to those generator interlock - a setup to ensure you won't switch on both the grid and the other power source at the same time. In this setup the connection will look like this:

|-- 100A supply tap breaker - 100A fused disconnect - EG4 GRID terminal
Meter -|
|-- 200 A Main Breaker -- Interlocked 200A breaker - EG4 LOAD terminal

The tricky part here is while it would function like a transfer switch provided the main breaker and the load breaker on the panel are interlocked - meaning there are physical metal piece installed so that it is impossible to switch both breaker on at the same time - it might still fail a inspection since it deviates from what the installation line diagram shows. You will be relying on the inspector's discretion for the pass / fail of this installation.

And I MUST stress that an interlock is absolutely necessary. This is to ensure no one is able to switch both circuit on at the same time ( which is the purpose of manual transfer switch ). When both breaker is on, it is causing a circuit short for all things between these two breaker, and it could either damage equipment or cause a fire. While you may know to do this in the correct sequence to avoid short, you won't always be the person touching these breaker.. So either manual transfer switch or interlock will be required to ensure there will not be danger by anyone flipping these breaker without knowing the specifics of how it is connected.

Another hurdle to jump is there are different interlock kit required for different panel and breaker arrangement / brands, and you won't always be able to find it for the arrangement you want. It is also generally required to be installed by a electrician to ensure you don't miss some important safe guard ( like the load breaker in this case will need to be screw down to the panel to ensure it can't be moved to evade the interlock etc.

So.. Please reconsider your original plan and definitely consult a electrician. Since a electrician will have enough knowledge to persuade the inspector when he comes, but you will have a much higher chance to get failed if you can't convince the inspector why this should still considered a safe install and adhere to code.

Wait. After typing all of this.. This is still a non starter.. You still won't get the whole 200A from grid this way.. so the same issue with your setup still applies - When EG4 is pulling or pushing more than 100A to the GRID side, it will still trip the breaker.

I am afraid this is a non-starter.. your best bet might be adding another critical panel right by this one, and hope that your circuits can be moved over to the critical panel without too much trouble.

A 100A service would cover my needs, so downsizing the fused disconnect would not be the end of the world, but unless I can at least remove the 3/0 from the meter to the main to allow a new connection, downsizing won't help. I understand the purpose of the MTS, but unless required by code I do not want it. A separate critical loads panel is not an option, so it looks like I have little choice but to replace the current combo panel. I really do appreciate the feedback. I was fairly sure this is where I would end up, and was hoping to be proven wrong.

Markus_EG4 said:

New workings modes is released here is the document

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smart!

Did you get tired of setting up people's inverter combinations?

nice work, this plus the parallel inverter settings recently added to the app are awesome additions!

Dan_Austin said:

A 100A service would cover my needs, so downsizing the fused disconnect would not be the end of the world, but unless I can at least remove the 3/0 from the meter to the main to allow a new connection, downsizing won't help. I understand the purpose of the MTS, but unless required by code I do not want it. A separate critical loads panel is not an option, so it looks like I have little choice but to replace the current combo panel. I really do appreciate the feedback. I was fairly sure this is where I would end up, and was hoping to be proven wrong.

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If you are going to get all of this inspected anyway, get a hold of an inspector and take some pictures and diagrams of what you have. They might be able to offer suggestions. Ripping out a meter and main panel is a big hassle even if you do it yourself. If you pay someone to do it, its $$$. I would consider all options before doing that. The 18KPV is a 12,000 watt inverter. That's 50 amps at 240 volts. Are you trying to inject the 18KPV between your meter and your panel? I know that is touted as a "feature", but I don't see the value in that. What do you do if your 18KPV fails. And it will fail eventually.

The goal is whole home. I laid out the system such that adding another 18Kpv later would be trivial. I really, really do not want to install a critical loads panel, as I would end up moving most circuits into it, but while mulling this over and examining the panel closer I realized it is 100% full and it does not support tandem breakers. So I either bite the bullet and install a critical loads panel that I will eventually replace or upgrade the main panel. The $$$ bugs me less than the fact that there is a lack of electricians in my area, I am already $$$ into an inverter and batteries that are effectively wall art...

Dan_Austin said:

The goal is whole home. I laid out the system such that adding another 18Kpv later would be trivial. I really, really do not want to install a critical loads panel, as I would end up moving most circuits into it, but while mulling this over and examining the panel closer I realized it is 100% full and it does not support tandem breakers. So I either bite the bullet and install a critical loads panel that I will eventually replace or upgrade the main panel. The $$$ bugs me less than the fact that there is a lack of electricians in my area, I am already $$$ into an inverter and batteries that are effectively wall art...

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At least this is a surface mount panel, moving circuit won't be that tricky..
Provided that there is wall space, get transfer switch, eg4 and the new panel mounted, and get a wiring trough long enough to reach all box. Use the trough to wire all the supply connection first.
Then pull your nicely labeled circuits and splice them in the trough so it can reach the new panel. The trough can serve as a junction box as well and should make this circuit move activity a lot faster and cleaner.
Just make sure to splice them neatly and label your wire on the other end as well.

I remember when I need to move circuit in my flush mount panel.. it takes quite a bit of time tracing which circuit does what and getting it to another flush mount subpanel is also quite a bit of work. I thought flush mount is nice before.. now I learned surface mount is much much easier to work with.

Having more panel give you more flexibility. After you have a setup that allows you to choose which panel to drop circuit easily, critical panel can be a easy way to handle the battery load when there is a brown out.

Dan_Austin said:

The goal is whole home. I laid out the system such that adding another 18Kpv later would be trivial. I really, really do not want to install a critical loads panel, as I would end up moving most circuits into it, but while mulling this over and examining the panel closer I realized it is 100% full and it does not support tandem breakers. So I either bite the bullet and install a critical loads panel that I will eventually replace or upgrade the main panel. The $$$ bugs me less than the fact that there is a lack of electricians in my area, I am already $$$ into an inverter and batteries that are effectively wall art...

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In case it's useful, this is the setup that I built at my cabin to power 200amp service:

Shinzul said:

In case it's useful, this is the setup that I built at my cabin to power 200amp service:

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If your service is 200 amps, then all 200 amps is available to the main panel with the switch in the "Utility" position. But power is also available to the inverters through the grid connections directly to the outside disconnect where they could be charging the batteries from grid. I believe the EG4 manual calls this "supply side taps". The combined load on the utility could exceed the 200 amp service limit as there are no breakers in the inverter grid connection. The 18KPV manual warns about this condition for the supply side tap configurations.

Perhaps you can argue the inverters are not set to do that, but there's no actual interlock to assure that. But that also means the inverter grid wires have no breaker protection (a short in the wires could draw lots of power from the grid, the breakers on the 18KPV won't stop that). So this doesn't seem safe to me.

The diagram in the EG4 18KPV manual (diagram 4.5 and other feeder tap configurations) shows a 200 amp breaker at the meter for just this sort of issue.

The diagram also shows combiner panels for inverter grid and load connections. Your wiring doesn't show that, which means the wires have to be 200 amp rated to the inverters to handle a possible wire short. The combiner panels seem to exist to allow using 60 amp wiring to the inverters.

Is your configuration code compliant?

Apologies if I am asking stupid questions, but I'm digging into how to configure an 18KPV system right now, and all the various diagram options are confusing.

mciholas said:

If your service is 200 amps, then all 200 amps is available to the main panel with the switch in the "Utility" position. But power is also available to the inverters through the grid connections directly to the outside disconnect where they could be charging the batteries from grid. I believe the EG4 manual calls this "supply side taps". The combined load on the utility could exceed the 200 amp service limit as there are no breakers in the inverter grid connection. The 18KPV manual warns about this condition for the supply side tap configurations.

Perhaps you can argue the inverters are not set to do that, but there's no actual interlock to assure that. But that also means the inverter grid wires have no breaker protection (a short in the wires could draw lots of power from the grid, the breakers on the 18KPV won't stop that). So this doesn't seem safe to me.

The diagram in the EG4 18KPV manual (diagram 4.5 and other feeder tap configurations) shows a 200 amp breaker at the meter for just this sort of issue.

The diagram also shows combiner panels for inverter grid and load connections. Your wiring doesn't show that, which means the wires have to be 200 amp rated to the inverters to handle a possible wire short. The combiner panels seem to exist to allow using 60 amp wiring to the inverters.

Is your configuration code compliant?

Apologies if I am asking stupid questions, but I'm digging into how to configure an 18KPV system right now, and all the various diagram options are confusing.

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My inverter grid inputs are on separate 100amp breakers outside just under the meter; one breaker per inverter with a set of 100amp wires going into each inverter (L1/L2/n/g)

edit: also, when the inside transfer switch is set to utility, it disconnects the inverters from the main panel completely, so there's no chance or risk of overloading the grid connection. I just realized my diagram is inaccurate - I need to update it to include the breakers

edit 2: there's also a 200 amp breaker between the meter and any of my other connections

Shinzul said:

when the inside transfer switch is set to utility, it disconnects the inverters from the main panel completely, so there's no chance or risk of overloading the grid connection

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With the transfer switch set to utility and the main panel drawing 200 amps, and the inverters grid charging the batteries, you have overloaded your utility connection and no breakers are tripping.

Mike C.

mciholas said:

With the transfer switch set to utility and the main panel drawing 200 amps, and the inverters grid charging the batteries, you have overloaded your utility connection and no breakers are tripping.

Mike C.

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There's also a 200 amp main utility breaker on the meter separate from the 2x100 amp inverter breakers haha.

I don't use utility power to charge the batteries though

Markus_EG4 said:

Here is the modbus protocol are you using this. If so what’s missing?

https://eg4electronics.com/wp-content/uploads/2023/06/EG4-18KPV-12LV-Modbus-Protocol.pdf

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That’s getting a 404 error, does anyone have a copy of this they could send me?

Thanks!

Found it: https://diysolarforum.com/attachments/eg4-18kpv-12lv-modbus-protocol-pdf.156504/

wpns said:

That’s getting a 404 error, does anyone have a copy of this they could send me?

Thanks!

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I have a copy on my personal website:

Shinzul said:

Ah, I've no idea how many are needed because I haven't seen them . Two sets presumably, one for each inverter.

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Replying back to my own message here, because I'm still kinda stuck in limbo. I have a ticket out with signature solar (@SignatureSolarJess - haven't heard back from you for 3 weeks ).

Their system says they have CTs in stock and ready to ship, but then whenever anyone tries to go look for them, apparently they're out of stock with no date as to when they could ship them.

@EG4_Jarrett any chance you could help on this front? I just need 2 sets of CTs (one for each inverter) .

Barring that - can anyone recommend a cheap CT I could buy myself to make it work? I'm not sure if the RS485 protocol for CTs is universal, but I suspect it would work...

The CTS are just a coil of wire, nothing more extravagant than that. There are three common turn ratios and most inverters will accept all three with the correct settings.