I have 2x 3.68 inverters and 2 x 8.2 batteries. in the evening when I'm discharging, the system seems to be seeing the house load and fulfilling it from both inverters & batteries. This means as well as meeting the say 1Kw house load, I'm also also exporting 1Kw. Thus both my batteries are low by morning when in reality they should power the house for at least 2 nights. Any ideas on how to sort this?
watching carefully
Will be interesting to see if they can work well as a plant.
Perhaps they are not configured properly as 'Master and Slave'?
GE came back and said I need to contact the Installers. Easier said than done these days. I contacted them before and they said its fine - didn't visit though. Will try again.
ToothyChris Do you know how I can check this?
DT42
As far as I know, the only way is to check the DIP switches, which will almost certainly be under the covers. They should be different, but I can't tell you exactly what they should look like, at the moment.
Perhaps one of the installers on here may know what happens if they are not set correctly (i.e. if it behaves like the situation you have described).
ToothyChris Thanks. This makes a lot of sense though as to the issues I'm seeing.
I'm really not convinced by my 2 inverter, 2 battery set up though. It's basically set up as; one does the front of the house and the other does the back. Given that a battery can only take about 2.6kW, on a sunny morning/afternoon I end up exporting as there's no overflow into the second battery, if you get me. i.e. if I'm generating 4kW on the front then 1.4kW is exported (even if the second battery is empty) and if the battery is full mid morning the inverter is exporting rather than filling the other battery. I have a 9.75kWh E-W set up.
A better set up for me would have been one, more powerful inverter and the two batteries wired in series.
It would be expensive to change now though, unless there is a good market for secondhand inverters?
DT42 From the two posts you've put up, it looks like you have two HY3.6, each with its own PV and battery. Each hybrid should have its own EM115 meter with CT. Both CTs should be monitoring energy flow between the consumer unit and DNO fuse (ie grid import and export) and each EM115 should be connected to one of the HY3.6s over Modbus (shielded twisted pair cable). When you are importing from the grid, both HY3.6s should ramp up to balance the import from its PV/battery. When one is exporting, the other should see this and consume the export to charge its battery. You should only ever export when both batteries are fully charged, the house load is being fed from PV and there is still surplus PV.
If this is not the case (which it appears not to be), then you need to get your installers back to check that the Modbus control system is working properly between each inverter/battery/EM115 setup. It may be that the CTs have been clipped on the wrong way round (arrow, which may only be visible when the CT is unclipped, should point towards the consumer unit, away from the DNO fuse). Each HY3.6 is electrically separate (apart from the fact that they are both connected to 240V somewhere in your house) and doesn't know anything about the other.
I've got a similar setup except I have HY5s and when they each go through a calibration, one battery discharges (into EV and house load) and then charges, being fed from the other HY5/battery as it is seen as house load. Yours should work with each other to supply house load and charge each other up before anything is exported.
Tim Wow thanks for this detailed response Tim, which is FAR more comprehensive than anything I've had from GE or the installer. It's good to know that what I thought I was getting is entirely possible and I don't have to export until both batteries are full. It gives me an avenue to chase too. Thank you, I'll go and explore the set up.
Tim When one is exporting, the other should see this and consume the export to charge its battery
I'm just thinking about this hard now ... My PV is all South facing, so both inverters see PV at the same time(ish). I'm certain that a charge of one battery (during calibration) is seen as house load by the other inverter and it discharges to meet the demand, but thinking hard now, in ECO mode, the hybrid inverter flexes it's energy supply (from PV and/or Battery) to meet house demand but doesn't divert export to charge its battery. To do that, you would have to manually set a charge on the inverter needing the charge. AC-coupled inverters do dynamically respond appropriately to grid import and export.
I think that part of the issue with AC-coupled inverter plant is that in the time it takes one to see export of the other and start to charge, the other is ramping down but sees the first as house load and so the two inverters play push-me-pull-you wasting energy. The hybrids don't look at consuming export to charge batteries dynamically and so (at least mine) play very nicely together.
Automation of export divert would be possible but it would have to be done through Home Assistant or similar and have to be set in a pecking order with hot water divert and EV charge divert, to whatever your priorities would be. I'm doing a similar sort of thing but it involves switching on an external 240V socket to charge a PHEV via a granny charger. I'm thinking that I will have to have been exporting at lest 2500W for at least 60 seconds before switching on the socket and leaving it switched on until import exceeds 500W for say 30 seconds. That means that if my EV is plugged into the Zappi, it will already have started as it's parameters are 500W export for 30 seconds. The automation also means I can also control the 240V socket to switch on during the off-peak charge period on a timer.
Tim Thanks Tim. I have an Eddi and a Zappi too to mop up the excess but if the car is not there then the excess is exported. I've had a look at the wiring and while I have no clue what's going on, the only CT clamp in the entire visible wiring is the Zappi one.
There is also the issue of the batteries discharging to the grid at night. It seems that the inverters see a load and both respond, leading to the excess being exported. I therefore wake up to see both batteries at about 25%. There should be enough storage to last me two nights not one. Somethings not right here, so although your system is all south facing and therefore different during the day, my night experience should be the same as yours.
DT42 My Zappi solar CT is in the consumer unit but the grid import/export CT is by the DNO fuse, alongside the two EM115 CTs. Do you know where your EM115s are? Is each one connected back to its inverter? The EM115s might be in your consumer unit or installed in a separate housing. Either way, you should be able to read instantaneous power on both to give you confidence that the CTs are connected correctly. If you don't know where your EM115s are, and there are no connections at the inverter, then that's a discussion to start with your installer. If they are there, then it may just be the orientation of the CTs which you can work out by checking them while a kettle boils. You should also be able to see the same data in the portal (Inverter - Meter Data) for each inverter.
DT42 the only CT clamp in the entire visible wiring is the Zappi one.
Our installer only installed the CT provided with the Zappi. We bought an extra one and installed it on the connection between our "solar" consumer unit where the two inverters are connected and the house consumer unit where the single large cable brings the PV to the house. This enables us to set the Zappi's Minimum Green Level and also see the solar input/output on the myEnergi app.
My Zappi CT is in the meter box outside.
Inside I seem to have one EM115 in a box between the two inverters. There's a black wire coming out of the box into inverter A, then the same type of wire coming out of an adjacent port in A and going into a port in inverter B.
I've removed the cover to the consumer unit box and the EM115 has a black and white wire going into a CT there, clamped to what looks like a thick red wire into a 100A fuse in the box. There is also another CT Clamp that looks like its connected to the two brown live wires coming from the inverters and going into the CU, that outputs into a grey wire going to the Harvi. Does that help?
DT42 Each hybrid inverter needs its own EM115. AC-connected inverters can be connected together over Modbus to create a single plant. If you have PV connected to an inverter along with a battery, its a hybrid. If you have no PV, just battery and AC connection, it'll be AC-coupled (unless the plan is to install PV to it later on, in which case there will be PV string input terminals.).
Only AC-coupled inverters, configured as a single plant, have one EM115. If you have two hybrids, each needs its own EM115. If you have one hybrid and one AC-coupled, each will need its own EM115. Do you know for sure what inverters you have?
The Harvi is to do with myEnergy, so don't need to worry about that CT.
If you have PV on the roof and only these two inverters, whether they are both hybrids or one hybrid and one AC coupled, they each need an EM115. I think a call to your installer is due.
Tim I have 2 Hybrid inverters the GE HY-3.6 and def only one EM115. I can't work out how to attach an image or I'd do so.
I was also thinking about the E-W config. There are two strings on each side of the house. Each side feeds its own inverter with the 2 strings via an armoured cable straight into the box. But would there be an issue with a string from each side going into each inverter, imagine a X. That way each inverter (and battery) gets fed morning and afternoon on sunny days, rather that just one inverter in the morning with the excess supply being exported.
DT42 You need one EM115 for each Hybrid. The last I heard, hybrids are not designed to work together as one plant and need to work separately. Your installer needs to put in another EM115 and separate the Modbus of the two hybrids.
Your inverters have dual MPPT, so you can run two strings and thus you could theoretically run one string from each orientation to each inverter. The issue will be whether you can reach the minimum voltage required with fewer panels on each string if you do that. An experienced installer would be able to work out what the impact of shorter strings would be on your overall annual output. It's not such an issue in summer when the sun is high enough to feed the PV but in winter, you could be in a situation where the shorter string struggles to meet the minimum voltage except for a short period during the middle of the day. With <10kWp E/W you might have got away with a single HY5 with each roof orientation feeding one string. On the plus side, you've got a much better plant to charge up two batteries during off-peak (if that's your plan) in winter.
Splitting the PV on each roof to feed separate inverters is a more difficult decision, but my gut feeling is that having all the PV on each roof on a single string will be better than splitting, whether the string goes to one or two inverters.
DT42 There are two strings on each side of the house
Sorry, just digested the detail. Doesn't change my gut feeling, but someone with better engineering knowledge would eb able to be more definitive about the impact on annual output. Swapping your existing strings so that each inverter has one string from each roof would seem to give you a good chance to get each battery topped up as best you can. Whether making a single string would be more beneficial is a really technical issue for someone else to advise.
DT42 .
I agree with @Tim that each hybrid inverter needs its own dedicated EM115 meter, as it is not a 'Plant' system that is only available with the AC coupled inverters. It does not sound like a supported configuration with 2 x hybrid inverters sharing 1 x EM115 meter on a single Modbus data network.
Out of interest how are the 2 inverters presented to you in the GE web portal, as 1 system or 2 separate?
It would be good if you could balance out the the PV strings to provide a more even charge of each battery over the course of the day. The ease of implementing this depends on how the PV string cables and local isolators are presented next to the inverters.
Just a guess, but are your panels laid out as 13 East + 13 West @ 375 W each, totalling 9.75 kW, with presumably separate strings of 6 and 7 on each roof? It may then be possible to configure as 6xE + 7xW to inverter A and 7xE + 6xW to inverter B. With 6 x panels on the smallest strings, there should be sufficient voltage to exceed the inverter startup value of 120/150 Volts depending on Gen1/Gen2 inverter models.
Simon_C Thanks Simon. The Gen1 3.6 HY inverters are shown separately on the portal. The numbers at the top of the dashboard are an aggregation of the two. Many of the aggregated numbers below this though are nil or rubbish e.g. Import 500,000kWh which apparently is a known issue at GE. This means that their portal isn't very useful and I use MyEnergi most of the time to see what's going on realtime.
At 8:50 in the morning, on a gloomy day I have exported 4.8kWh already, most of this in the small hours when there was minimal base load, 300w. Two full 8.2kWh batteries at 6pm yesterday now have 8%! This is the sort of behaviour I want to stop.
For info I have 14 x 390W panels west facing (5.46kW), I assume 2X7 strings and 12 x 390W east facing (4.68kW), I'm guessing 7+4 as thats how they are arranged. 26x390= 10.14.
DT42 ,
Assuming your installation was to MCS requirements, you should have a schematic diagram showing the configuration of the 4 strings split across the 2 inverters.
If not, then recording each string voltage and power from the GE web portal at say 0900, 1300 and 1700 BST should give a good indication of which and how many panels are connected on each specific string.
GE support should be able to clarify if 2 x hybrid inverters with 1 x EM115 meter is actually a supported configuration. If it is not supported, then you have a strong case to insist the installer returns to rectify, presumably by providing, installing and configuring a 2nd EM115 meter with separate comms to each inverter.
Simon_C I'll contact GE support today. Seems to take a week to get a response though.
Tim Hi Tim, you mentioned your hybrids are working fine together.
Yesterday I installed two 5.0kW hybrids each with a 9.5kWh battery. They are each on their own EM115, but it seems there is cross charging, ie one battery is discharging to charge the other.
Please could you give any advice? Yours is the first post I've seen really mentioning this issue hence the reply in this old thread.
TempleSolar Cross charging is a feature of AC-connected inverters. If yours are hybrids and the output of one is being consumed by the other, then it'll be because the batteries are being calibrated. By default, the hybrid inverter never consumes energy from grid unless there's a calibration or timed charge in progress.
Tim Thanks for your reply on such an old thread, I appreciate it.
I can't see any indication that either battery is being calibrated but there may be a sign I'm missing. From what you've written, it sounds like it could sort itself out over time? I wondered if I should try flipping the polarity of the CT clamps remotely?
I should mention, there are no timed charges set on either battery / inverter.
Thanks again
Hi,
I’ve got a similar set up. 2x 5.0 hybrids and 2x 9.5 batteries on each inverter. 2 inverters and 4 batteries in total.
They do (or did) discharge from one battery to the other. They cross charge because while one battery is charging (load) it is seen as a demand by the other inverter, so that one discharges its battery into the other one, then they may swap over or not. It’s not apparent when there is good solar generation.
There are two solutions at the moment.
1) Ask support to get the system put on the “balancing” trial.
2) Wait for the hardware EMS to be released and install that. But no one knows when that’ll be released yet.
The balancing trial is a software version of the eventual hardware EMS and works by pause/ play commands sent to the inverters by GivEnergy. The hardware version should be much faster to react (being local). But I assume will do the same/ similar thing?
Hope that helps.
Pete UK I don’t think it does help. You are right that if one inverter is charging its batteries from grid while the other is in ECO mode, the one in ECO will discharge to meet the load. This can happen during a battery calibration.
The hybrid inverter will never consume energy from the grid (or present as a load on the consumer unit) unless it is set to a timed charge or routine battery calibration or you’ve triggered a manual charge on the app. If the inverter is in ECO mode, it won’t charge from grid, only solar. Or at least that’s the case with gen1 inverters. Maybe gen 2 or 3 do something different.
Thanks for the input. However….
It’s nothing to do with charging from the grid.
Nothing to do with calibration.
Nothing to do with timed charge/discharge.
Both inverters in eco mode, no timed charge/ discharge set and they cross charge each others’ batteries. For example: Overnight, no Solar and no grid import/ export you’ll see; battery A: discharge rate at a constant 3.7kW and battery B: charging at 3,700kW ! Then they might swap around a few times and the rate may vary but usually one inverter is dominant. This results in unnecessary cycles, and power wastage due to losses neither of which is desirable or what should be happening. There are plenty of posts about this phenomenon.
@TempleSolar is talking about one battery cross charging from the other one; On dual 5.0 hybrid inverters with batteries attached on each. This is a problem that many with the same set up are currently having. The final solution in the pipeline is the EMS (energy management system) which is currently being beta tested. Or getting on the battery balancing beta testing (which as I mentioned earlier is a software version of that).
I don’t know why they can’t just add some sensors to the batteries/ inverter and some logic so that, for example, if A is discharging and B is charging: Stop B charging? Or ideally: Both discharge at half the house demand rate, Plus whatever other logic they need for the other scenarios. Surely that’s not hard?
Maybe this is what will be in the EMS box. But despite asking I’ve not got an answer yet.
In the meantime, there isn’t anything else you can do, except try to solve it with home assistant, or the other 2 options I suggested.
Pete UK I can see that if your hybrid is seeing house load, it will try to meet that demand from battery or solar and that is what I would expect it to be doing in ECO mode. However, if your other hybrid is randomly discharging at full power, then that is a fault condition, unless you've set a timed charge/discharge or a calibration is happening. You say this isn't the case. IMHO you don't need the EMS at all, you just need Givenergy to fix the fault that triggers the random (or timed?) discharge.