New here, but not new to off-grid and solar stuff.
I work as a lecturer at a TAFE college in Western Australia, and with the help of a dozen students and some staff, we’ve set up a completely off-grid solar array, battery and EV charger using Victron gear. We have two arrays of about 4 kW worth of reclaimed panels (arrays are 10 strings of 3 panels, all paralleled at a combiner box) and these supply two MPPT 150/70 charge controllers. The battery is a 360 Ah, 48 V LFP battery with a Seplos 3.0 BMS talking Victron to the Cerbo GX. The battery powers a Multiplus II 10 kW inverter which in turn supplies a pair of Schneider AC charge points in the staff car park.
Getting into the darker months, we’re anticipating EV charging demand while sun is a bit weak. In an effort to keep the battery in a reasonable state of charge, we’re keen to have the Inverter turn itself off should the state of charge get as low as 15%. This would give it time to recover to about, say, 40% when the sun comes out later in the day. Then, the inverter can be turned back on ready to power the charge points again.
It seems like the most sensible way to do this is to get the Cerbo GX to stop the inverter from inverting when 15% SOC is reached, and turn it back on when it gets to 40%. But I can’t see how I might do this on the control panel. We have the VRM set up so I can turn the inverter off remotely, but I don’t want to be watching this thing every morning like a retiree checking his stocks!
We have attempted a workaround with Relay 1 of the GX unit - we’ve wired the remote enable loop on the inverter through the COM and NC outputs or relay 1, and called this the ‘generator relay’. If the SOC is 15%, the generator relay turns on, breaking the NC loop and switching the inverter off and letting the battery recover. Unfortunately, because the inverter is not powered, it loses all comms, so the GX won’t talk to it. The only solution is to unplug the RJ45 plug, allow the inverter to wake up again, and then plug it back in again. Great, but not exactly a remote control solution.
That is an excellent project for the students to have been involved in as this will undoubtedly form a larger share of electrician / electrical engineering in the years to come.,
There are 2 possibilities that I can think of. The first is the inverter has this setting natively. You have to enable the battery monitor and then set the SOC shutdown.
The second is to download the large image of Venus OS onto the Cerbo and enable something called Node Red. Node Red is a graphical programming / sequencing code that runs on the Cerbo and can control the attached peripherals.
arrays are 10 strings of 3 panels, all paralleled at a combiner box) and these supply two MPPT 150/70 charge controllers
I do hope that this is not quite true, the PV inputs to 2 MPPT’s should not be paralleled unless they are set up as master and slave…
For the control issue, the Venus large image and Node Red would be the way to go.
There are two 150/70 charge controllers supplying the one battery. Each of these charge controllers is itself supplied by one of the arrays, both of which are 10 paralleled strings of 3 panels. Being 12 year old panels they’re putting out about 4.5 A peak at 90 V.
I just read that AC outpur 2 on the Multiplus has a relay behind it. If it’s possible to power the charge points from this, and we can control that relay, then that will acoid the inverter being shut down completely and losing comms. Question is, how to control that relay.
I’ve not had to use VE.Configure yet. It’s a Bluetooth App I guess?
Guessing and power electronics never mix well.
No it’s not bluetooth. Old-fashioned windows application. A mk3 adapter is needed. Alternatively configs can be pushed remotely over vrm if the system is online.
I repeat this a lot, but there is excellent, free video training at professional.victronenergy.com
Spend some time there it will really fill in the gaps.
Every product and tool has a dedicated manual.
There is an assistant (general relay?) on the inverter to control AC2 - many topics on this subject are lurking on the forum.
Well I downloaded Victron.Connect onto my laptop. Bought the MK3-USB-C interface, plugged the patch lead into the VE Bus of the CerboGX and the other end into the new gizmo, and the USB-C into the laptop. It seems to identify the two charge controllers and the CerboGX, but not the inverter.
SO I plugged it directly into the inverter without the Cerbo, and it’s still not picking it up. The mosquitos were getting bad late in the afternoon so I called it a day and will have another look on Wednesday.
Edit - Just downloaded VE Configure - hope to try again soon…
Thanks, yeah did all that. I think I have the right software set up now - I was trying to do it via VE Connect but it turns out the inverter cannot be configured remotely - hence the VE Configure download.
OK might have another crack at this tomorrow, but I tried mid last week and got nowhere. I have a USB3 port on my laptop and a patch cable between the inverter’s VE Bus and the MK3 gizmo. I’ve got VE Configure 3 on my laptop and will try to connect to it again. I didn’t seem to get to the point where it recognised the device.
