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A very almost chucked a USB-ttl-serial converter in the bin once... only to discover I had accidentally left some process running in the background that periodically tried to talk to any detected serial ports. That script is also used a lot when debugging something or doing support. You can rip the process out of the serial-starter loop, and run it manually. When done, simply put it back into the loop with the start script. Something I did not mention last night, which you will also have to figure out in time: Daemontools. Venus manages those services using daemontools. You'll have to create a service directory for it (just borrow one from the others and modify). This then gets symlinked into /service, and the service is automatically started when Venus boots. But... during firmware updates, your symlink will be destroyed. Not an issue though, Venus will run /data/rc.local at boot, so you can use that to restore the symlink if it does not exist. Further to that, if you put a file called venus-data.tar.gz (or venus-data.zip) on an sd-card, and put it in the GX while booting, it will automatically unpack this in /data. With all that information, you can literally build an installer that unpacks your code into /data, and using rc.local, symlink the service into place. Customers install it by putting a zip file on an sdcard, inserting and rebooting. Easy peasy 🙂 Edit: For those who wonder what the hell a symlink is... it's like what Windows used to call a "shortcut"... except the file system handles and file operations transparently, and Unix had it in 1984 already.

Sure, but personally I don't have the patience to wait for it to ship, nor do I want to take the risk of using the Post Office, and if you add courier cost you have to bring in larger volumes to get good pricing. And then SARS wants their cut and you end up having to register as an importer if you do this more than a few times a year. I suppose if someone does this as a business venture, then yes... you can get that low. I actually don't see a problem with the cost of an arduino, even if you buy it from RS components 🙂 Compared to the cost of the rest of the stuff that is cheap. What is attractive about the Arduino route is that it becomes a separate concern. You're not locked into some version of Venus (or at least less locked). I mean, you're already not locked, but things change over time. We're moving to python3 in a future release for example (2.70 probably). Also, it opens it up to other inverter makers. And fixing something or supporting something new is just a firmware update. Regarding the isolation, I'd just use a Texas Instruments ISO1050 CAN transceiver chip instead of the MCP2551 most shields have. It's not exactly a drop-in replacement (unfortunately, it needs its own isolated power supply on the other side), and it's an expensive chip, but again, it's cheap enough. Still, I've seen some of @Louisvdw's code, and a man who knows how to use the struct module most likely isn't some beginner to the space of packing binary data. I'd like to see what he comes up with. Also, knowing what I do about the ICC people (who use the console cable to talk to the Pylontech battery), I already know that there is a certain preference for using cheaper cables over more expensive ones, so a software+usb-serial combination may well find better traction than a hardware solution. Since I own an arduino with a canbus shield -- I use it to fake can-bms batteries that I don't own -- I actually like the hardware idea a little bit more... 🙂

That would actually be insanely useful. It would cost a bit (arduino plus can-bus shield), but really easy to implement. A driver for Venus would of course be cheaper to the customer. No extra hardware. It can also be made to install/update from sd-card and to survive firmware updates... just saying 🙂

Just do a before and after test. Disconnect the wire, measure voltage from neutral to earth (while running islanded of course). Repeat with wire connected. Post the results here so someone else can google into it. 🙂

Just to add my voice: Never ever do this. If you electrocute someone by feeding into the grid, you can get into serious legal trouble, we're talking manslaughter charges or at least endangerment. Spend the R350 and install a Hager SFT240 changeover.

Testing testing... / etc /venus /serial-starter.conf But if I take the spaces out... it complains.... gaah...

Yes. Call start-tty.sh instead.

Also see here: https://github.com/victronenergy/venus/wiki/howto-add-a-driver-to-Venus

Let's try this again. Venus starts one process after the other. The process is defined in a file called slash etc slash venus slash serial dash starter dot conf. Sorry about typing that out... but I am seriously forbidden from just typing it. Once your driver works, you can add it to that file. The rule is that if your software doesn't detect the expected hardware, it simply terminates. Serial-starter then simply calls one process after the other until one sticks.

OK.... the forum software does not want me to tell you more. Sorry... it keeps giving me 403 if I type path names.

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That ^^^ Venus has something called serial-starter. When it sees a USB device, it tries to start some kind of "driver" for it, usually vedirect or the cgwacs RS485 software. When that happens, two processes are reading the same serial port, and you get this sort of behaviour: The serial port reports that there is data, but by the time you get there to read it, the other process has already removed the data from the buffer. If you want serial-starter to leave the port alone, tell it like so: # /opt/victronenergy/serial-starter/stop-tty.sh /dev/ttyUSB3 After running that command, serial-starter will stop attempting to find something to do with that device...

Weird... so am I, and I don't really see any issues. I think it does depend on your neighbourhood though. When I lived down in Somerset Ridge, I had a much more stable voltage than I do now. Difference between a house built in 2004 and one built in 1975 🙂

I heard the same thing. Presumably, the BMS itself loses power, and it needs to get power from somewhere in order to allow power to go to the cells. In that case, using a good battery charger should have been enough to raise the voltage and restart the BMS. When we tested it, the battery charger was applying 14.5V (absorption), but putting an ampere meter in line showed mere milliamps flowing for short periods... almost as if there is some kind of electronics in there that's trying, but not succeeding... Battery was under warranty, so we decided not to... uhm... investigate any further. Also, not sure it was the same battery as this one. But it looked identical.

Just split it down the middle... Poor Tony's gonna get the brunt of it, but it's probably fair? Ek en my skoonma... bly in 'n woonwa... 🙂

Could be the same guy even. Happened right around the time our lockdown started. We may be talking of the same friend of a friend. Boeta (probably a nickname) arrived here in his Disco... we had one last look but the battery would not even accept a charge current. Looked very similar to the pictures above.

Friend of mine was here some months ago, with a similar-looking battery, though I cannot remember the brand name. Dead. He was told the Victron 12V charger would lift it out... but it had no effect at all. I think they junked the battery in the end.

@Weasel explained the other day that there is an unmarked terminal that you simply need to earth, and the bond will be made. Apparently the reason they do it that way, is for flexibility. It allows you to connect that to a local earth spike (if so required in your area), or leave it unconnected and instead bridge the neutrals (TN-C-S setups), or earth to the council earth. I've never seen one of these machines in the flesh, so you may want to check yours to be sure.

Right. So I suppose it is important to explain that this TN bonding isn't handled the same in every country, and as @Coulomb pointed out in the past, it is certainly less of an issue in Australia and NZ. Even in South Africa, if you have a TN-C-S connection to your supplier, ie the main breaker in your kiosk (meterkast in Dutch) is single pole, and you install the inverter at this point, then you can simply connect the input neutral and output neutral together and be done. But the majority of South African installations are not like this. So the options are: 1. Simply bond TN together on the output. This violates SANS (which requires that earth conductors should only carry fault current). 2. Connect the input and output neutrals together. This violates SANS (which requires that you don't rely on the council-side TN bond for islanded operation). 3. Install a contactor with normally-closed contacts that's powered by the grid, and use a NC contact to bond TN. When the grid fails, the contactor installs the bond. This is no good for systems with solar power, since those systems may change to islanded operation while the grid remains on. 4. Do nothing. Without the TN bond a singe earth fault may not be enough to trip an RCD (aka earth leakage), but in such a case a single earth fault also doesn't electrocute anyone. Only the second fault trips/electrocutes. 5. Open the inverter and modify it internally so that you can get a signal from the changeover relay, and use that to make your own bonding box. Voids warranty. 6. Replace the inverter with one that complies. The first 4 are not compliant of course.

Well, there are ways to do it legally. It requires a bit of paperwork, and sometimes you need an engineer to sign it off (depending on system type).

One way I've seen neutrals traced... let's call this the cowboy way, is: 1. Make sure every circuit has a load connected, like a lamp or something. 2. Turn off all the live breakers. 3. Remove all the neutral wires from the neutral bar. 4. Turn on one of the breakers on the live side. 5. At this point, one (or more) of the neutral wires that are hanging in mid air is now live (the current goes via the breaker you have turned on, through the load you left plugged in, to this neutral wire. Now you can do one of two things... 5.1. Cowboy squared: Take each neutral wire, being careful not to touch it, and tap it against the neutral bar. If you see a small spark, that's the wire corresponding with the breaker currently turned on, or... 5.2. Use a digital multimeter and find the neutral wire that has a voltage on it. This method is of course preferred. 6. Mark wires in some way, then go back to step 4 until complete. 7. Don't end up dead. Work with one hand in your pocket so you don't accidentally form a path across the heart. 8. Wear rubber shoes. 9. Don't end up dead 10. Don't do any of the above, rather use the resistance test or clamp meter test suggested above.

Buy a proper inverter that does it right... OK, I'm kidding, well, half kidding. This question comes up twice a week 🙂 First Axperts (circa 2013) had no proper bonding in place. Later versions had a firmware setting (38 I believe from a quick google) that could be enabled. This would then use the internal relay in the inverter to switch an external bonding relay that would tie T and N together when running islanded. Later versions of the Axpert (2017 ish?) had a proper fix and bonds TN using the same relay that switches the neutral side of the grid connection. I doubt there can be very many of the 2013 vintage Axperts still around, since they generally don't last that long, so you will probably have the firmware setting as mentioned. If not, revert to the first sentence of this post 🙂

All earths are always interconnected and should not be interrupted. The AC-in, out, etc will have their earths connected together. In other words, this is already connected to the earth provided by your supplier (for a TN-C-S connection, there will be an earth spike on your premises, and for a TN-S setup, the earth is at the transformer and you have a separate earth going back all the way to the transformer). The advice I've been given is to earth everything to the same earth point. The earth provided by the supplier is usually of excellent quality and better than anything you can sink (unless you sink several spikes to get the resistance low enough), so in most cases, if it shows a low earth impedance, you can use it for everything. I'm not an electrician though, so confirm with one 🙂

Correct, that is what happens. Ideally one should have just one RCD in "series". In cases where you must have two, the upstream one will have a slightly higher leakage current specification, to ensure that the closest one trips first. If you do this, then of course the upstream one cannot feed plugs directly. Plugs must always have a 30mA RCD. In my experience, a good deliberate leakage (eg RCD tester) will trip both RCDs, but nuisance tripping will trip the more sensitive one first.

That's good. In my own setup I put the changeover before the earth leakage breakers, so that the earth leakage on the output of the inverter is always used for the backup loads. The way you have it wired here (though perfectly fine and safe) means that your output loads are moved to the other RCD when bypassed. Which is fine, but I like to keep them split especially since standing leakage currents for the whole house, when using modern appliances, can be quite high already.