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My new installation: Inverter + Hubble + (Solar in future)


Mier
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(Also posted on MyBroadband, but discussion is a bit slow)

I'm about to start down the rabbit hole...

My initial setup will be to beat loadshedding, but with the aim to include solar generation in the future.

I already have an inverter which I bought last year on an impulse. It's a Soltra GTB3000 3KW Plus, which appears to be an Infinity Solar 3K+ rebrand/clone. Not much information available for this unit, but it seemed decent for the R6k I paid for it, so will see.
With some searching I managed to find the user manual and software. It's still boxed, but I did test it briefly plugged into a wall outlet and was able to connect using the SolarPower software and the supplied USB cable.

I also ordered a Hubble AM-2 battery.

The plan is to install a new DB for essential load and move all lights and plug circuits over to it, except for: Aircon, Geyser, Washing Machines, Tumble Dryer, Dish Washer, Microwave, Ovens and Swimming Pool DB.
All the lights in my house are already LED.

I want to do most of the install myself and then have it checked and CoC'd by an electrician.
I had two electricians over to quote, but they didn't inspire much confidence and were rather expensive, I thought.

I do have a few questions and will also appreciate some comments, hence this thread.

This is what I plan to build (may not be perfectly to scale):

image.thumb.png.6f17567f1f0eccfe0d7fd3659ddd0c97.png
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2 hours ago, Vassen said:

Nice 

 

I don’t see any surge protectors in those DBs though. Not sure if it’s mandatory but it’s definitely nice to have 

also remember that AC and DC lines should be kept totally isolated. Meaning separate trunking / conduits. 

Thanks.

There's a surge protector in the existing Non-Essential DB on the far right. I supposed I could easily add one to the Essential DB between the Main and Earth leakage, or should I rather add it in the Switch-over DB between the Inverter Breaker and the Change-over switch ?

Yes, trunking will be separate. I just couldn't install it yet because I only received delivery of the battery today and therefore couldn't measure the trunking length.

The DC Trunking will be below the AC trunking (the battery connectors are on the bottom right of the inverter.

On this point, is it allowed to cross the AC trunking? I was think of a closed trunking link:

image.thumb.png.b748e62c9f8ff1f1021562b23af9a4a6.png

Or maybe doing the same with sprague links for the DC running through the AC Trunking.

Surely this would be acceptable as it remains separate trunking with just a slight 'narrowing' of the AC trunking at that point.

 

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Does the Soltra Inverter have the capability (programmable contact), when working in battery mode i.e. during off grid (e.g. load shedding), to trigger an output for an external relay to bond the neutral to earth?

If not, then the RCD (essential loads - earth fault) during off grid mode will be non- functional, which becomes an safety issue.

I browsed the manual quickly but could not find this function.

note: 1. include the external bonding relay to your circuit (Ess. DB) which interfaces to your inverter, if the function exists.

         2. I am assuming that you have included fuses within the battery disconnector circuit.

         3. I would also recommend surge arrestors within non essential DB to protect your equipment from utility switching surges or lightning strikes

       

 

 

 

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1 minute ago, Alex Feldmann said:

Does the Soltra Inverter have the capability (programmable contact), when working in battery mode i.e. during off grid (e.g. load shedding), to trigger an output for an external relay to bond the neutral to earth?

If not, then the RCD (essential loads - earth fault) during off grid mode will be non- functional, which becomes an safety issue.

I browsed the manual quickly but could not find this function.

note: 1. include the external bonding relay to your circuit (Ess. DB) which interfaces to your inverter, if the function exists.

         2. I am assuming that you have included fuses within the battery disconnector circuit.

         3. I would also recommend surge arrestors within non essential DB to protect your equipment from utility switching surges or lightning strikes

       

 

 

 

On your points:

1) No it does not have such contacts. If this is required, I was thinking of using a Relay switch (activated by Grid, with the Normally Closed contacts connected to Inverter Earth and Neutral) - This way when Grid is present the Relay is open and Inverter Earth+Neutral is not bonded, when Grid is off, Inverter Earth+Neutral is bonded. This should accomplish the same, I think. I did want to test this first, because I thought it's also possible that the inverter does the bonding internally when required.

2) Yes, I bought a fused battery disconnector this morning. To be installed.

3) There already a surge protector in the Non-Essential DB. Still trying to determine if there is another one also needed for the Essential DB.

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21 minutes ago, Alex Feldmann said:

Does the Soltra Inverter have the capability (programmable contact), when working in battery mode i.e. during off grid (e.g. load shedding), to trigger an output for an external relay to bond the neutral to earth?

If not, then the RCD (essential loads - earth fault) during off grid mode will be non- functional, which becomes an safety issue.

I browsed the manual quickly but could not find this function.

note: 1. include the external bonding relay to your circuit (Ess. DB) which interfaces to your inverter, if the function exists.

         2. I am assuming that you have included fuses within the battery disconnector circuit.

         3. I would also recommend surge arrestors within non essential DB to protect your equipment from utility switching surges or lightning strikes

       

 

 

 

 

6 minutes ago, Mier said:

On your points:

1) No it does not have such contacts. If this is required, I was thinking of using a Relay switch (activated by Grid, with the Normally Closed contacts connected to Inverter Earth and Neutral) - This way when Grid is present the Relay is open and Inverter Earth+Neutral is not bonded, when Grid is off, Inverter Earth+Neutral is bonded. This should accomplish the same, I think. I did want to test this first, because I thought it's also possible that the inverter does the bonding internally when required.

2) Yes, I bought a fused battery disconnector this morning. To be installed.

3) There already a surge protector in the Non-Essential DB. Still trying to determine if there is another one also needed for the Essential DB.

I would only install within the non essential DB for this application.

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21 hours ago, Mier said:

Thanks.

There's a surge protector in the existing Non-Essential DB on the far right. I supposed I could easily add one to the Essential DB between the Main and Earth leakage, or should I rather add it in the Switch-over DB between the Inverter Breaker and the Change-over switch ?

Yes, trunking will be separate. I just couldn't install it yet because I only received delivery of the battery today and therefore couldn't measure the trunking length.

The DC Trunking will be below the AC trunking (the battery connectors are on the bottom right of the inverter.

On this point, is it allowed to cross the AC trunking? I was think of a closed trunking link:

image.thumb.png.b748e62c9f8ff1f1021562b23af9a4a6.png

Or maybe doing the same with sprague links for the DC running through the AC Trunking.

Surely this would be acceptable as it remains separate trunking with just a slight 'narrowing' of the AC trunking at that point.

 

 

I'm experimenting with an alternative bridge that will cross the DC trunking over the AC trunking:

image.thumb.png.5c9547c2ac32f3c12eb8451090fa9284.png

 

image.png.50a336230bba5eaaf345d53267eb83b5.png

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2 minutes ago, Brani said:

Be mindful that your DC cables are much thicker and you might struggle to bend them twice at 90 degrees in such short space.

That's why I call it an experiment for now 😄

The trunking is 80mm x 40mm, so hoping that will give me enough space. The longer end, stops against the wall, and the idea is to put glands  on the top surface which faces the inverter.

There's also the possibility of only attaching / fitting the bridge after the cable is in. (It will also be removable. The portion of the AC trunking lid below the bridge will be cut either side of the bridge and fixed to the bridge. That way it will be easy to remove and manipulate cable through)

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On 2021/04/06 at 3:22 PM, Tariq said:

Jaco De Jongh had once told me that it is ok to cross ac and dc wiring ( @Jaco De Jongh, please  correct me if I am wrong)

Correction, talked to Jaco, looks like I simplified it too much, you CANNOT cross AC and DC wires unless unless they are in separate trunking or sprague is what I meant to say

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More progress. Battery is connected and most of the switch-over DB and Essential DB wiring is done.

No wiring from Non-Essential DB (Grid feed to Inverter), nor any circuits moved from Non-Essential to Essential DB yet.

I did switch on the Inverter from the Battery and it seems to work fine. Also connected a laptop via USB to it and established SolarPower comms.

image.thumb.png.7bf057ceea7990abd745abab8b75dcc9.png

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Finally the inverter is integrated with the main supply (non-essential DB) !

 

I have also connected the first "Lights" circuit to the essential DB. Everything is working perfectly. Battery is charging, automatic fail-over when grid fails/recovers etc. etc. (Lights don't even flicker when switching between Grid and Battery). Though I've connected the inverter input from a EL circuit, it doesn't trip the main EL so far when switching between modes (bypass / backup etc)

 

I had to replace the switch-over DB with a larger DB to have space for a Inverter Earth+Neutral Bond Relay switch. I had to add this as I found that when the safety relays disconnects the grid, then I had a Earth / Neutral potential of ~110V. The bonding relay is switched by the grid, so when grid is present the bond is disconnected, when grid is off, the bond is made. (I prefer not to make a permanent EN bond.)

 

Next, I'll get a CoC done and move more circuits over to essential.

 

 

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Looks fantastic! Great DIY job!

I'm just about to embark down the same route (I have purchased the majority of my items), but I'm still not 100% sure how to run my wiring.

Please can you attach a photo of your neat setup, but without the trunking covers on? I would like to understand how you did your wiring.

My biggest concern with my wiring is that the inverter has the PV input on the bottom left, AC input and output on the bottom middle and the battery input on the bottom right. This makes it nearly impossible to run trunking without having wires crossing. The only way to do it would be to bring the PV wires in from the top and down the left, the AC wires from the bottom, to the center and then the battery cables in from the bottom right.

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Thank you😊

 

Here's a close-up of the portion under the Inverter where the AC and DC cross. (The Grey loose cable is just a USB cable to the laptop I have plugged in at the moment)

image.thumb.png.4cc65f1423cb7a248a18701a404477ee.png

On the left is the Inverter AC Input (Grid) and Output and runs in the top trunking.

It's pretty much following the trunking sketch a few posts back.

 

The AC is running in the yellow trunking and the purple is DC. The thinner vertical trunking is where the PV will come down (one day). 

image.png.df1c382fa729c7acdb1a0273caaacf44.png

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Thank you for the photos - great setup!

I see you put in a relay for your earth to neutral bonding. This works perfectly as there is presently no PV input for your system. Hence, when mains is running, the system uses the normal Eskom earth to neutral bond, and when the system runs in "UPS" mode, the relay closes, bonding the earth earth neutral.

Having done a large amount of reading on the topic over the past few days, there appears to be a lot of confusion on this topic 🤔 some say it must definitely be bonded, others say no way. Does your inverter specify that the bonding is required? Or did you measure the line voltage and if so, did you have a floating earth?

Once you have PV, this won't work, as the inverter will have both mains, PV and battery supply available, so there isn't a way to switch the relay based on output.

Edited by Schnavel
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Lots of confusion wrt the bonding indeed. 

No, the inverter manual didn't specify anything, but I had a ~110v floating Neutral between E and N, which I wasn't comfortable with. I decided to add it for now, though I'm aware it will be problematic once I add PV. 

The things is, being based in Somerset West (City of Cape Town), I might not be allowed to add PV to this inverter anyhow because though it was on their 2019 list of approved inverters it isn't anymore. If my eventual application is rejected, I may be forced to change my inverter, in which case I might go with Sunsynk, which I know has E&N bonding contacts for a relay. 

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