It should close its contacts when SOC is lower than 10% and it should open the contacts when SOC is higher than 40%.
It seems to be very easy but in my system the relay 1 doesn’t work at all – it doesn’t show any reaction be the SOC as it may…
What I configured is the following:
1st step:Settings → Relay → Function Relay 1 → Generator start/stop (see image 1)
2nd step:
Settings → Generator start/stop → auto start functionality → (shift the slider in position „on“) (see image 2)
3rd step:
Settings → Generator start/stop → Settings (generator start/stop) → Conditions → Battery SOC enabled → Use battery SOC value to start/stop → start when battery SOC is lower than 10% → stop when battery SOC is higher than 40% (see image 3)
4th step:
Settings → General → reboot
The relay 1 does not work …. - did I forget something?
I would be very thankful for any help in this issue.
Config seems to be correct.
What happens if you trigger a manual “generator start”?
Does the relay respond to that?
If you don’t hear the relay “click”, you might have a broken relay.
If it clicks but no action is triggered, you might have a fault in your wiring to the relay.
By the way: if you’re using the same percentages for normal hours as quiet hours, you can just disable that feature altogether.
Edit: some hardware & software info of your system would be very useful.
On what kind of GX device are you running which Venus OS version ?
Dear Bart Champagne,
thank you very much for your quick response!
The idea to try with manual “generator start” is very good. Because the installation is situated in a partner school in Tanzania (myself I’m in Germany) I will contact my colleague there and tell him this news. He will try this feature and I’ll give feedback soon.
…“if you’re using the same percentages for normal hours as quiet hours, you can just disable that feature altogether” - how can I do this? Could you explain me, please?
A bit more in detail about our system: It was installed in 2023. It is a 5 kW-solar installation, only AC-coupled. No use of any MPPT. The PV-inverter is from SMA, it is a “Sunny Mini Central 5000A”. The battery inverter is Victron Multiplus II, 48V-5000, separately connected to a Cerbo GX. The battery system is from WECO (Italy), it performs well with Victron, 3 batteries from the WECO-type 5k3, all together 15,9 kWh capacity. That’s all - a pretty simple system.
We would like so much to trigger the relay 1 depending on SOC in order to give support when the batteries are down. (But in reality, we don’t have a “true” generator - our “generator” is the Tanzanian grid.) Therefore we already installed a contactor and wired it correctly with the Relay 1 of the Cerbo. Before installing that I made sure that the coil of the contactor does need too much current with regard to the current carrying capacity for relay 1. Everything is working correctly so far: If we bridge the 2 cables for relay 1 manually then the contactor attracts and connects the Multiplus with TANESCO (Tanzanian grid). But up to now we were not able to configure the Cerbo so that this runs automatically… We tried to do everything - it was in vain. But it must being said that we are new with Victron.
Hope to hear from you again. Thank you very much.
You say that you used the relay in the Cerbo to drive a contactor, bit did you consider the surge voltages and make sure you had a contactor with protective diodes to prevent Cerbo relay damage. You should tell your colleague to set Relay 1 to manual operation, disconnect the contactor then test for resistance on the NO and common terminals when the relay is on and off to make sure it is working. You may have damaged the switch part of the relay, many people have done this when driving a contactor without using a proper contactor or adding extra diode.
Another solution to your problem could be to always stay grid connected and configure ESS.
Set a very low grid setpoint (50W), enable “Optimized with Batterylife” mode and set minimum SoC to 10-20%.
That way the system will use as much from the batteries as possible and when they’re empty the system will automagically start taking power from the grid.
This will require reconfiguration of the Multi but that can be done remotely.
You could also program the Multi to “Ignore AC In” depending on the state of an input contact.
The Multi input contact can be wired to a GX relay that is driven by the generator function you’re already trying to use.
The added advantage of this option is that you’re not driving a large relay with the small GX relay so there’s no risk of burning the GX relay, as @pwfarnell already pointed out.
Edit: all depends of course on the GX actually knowing the SoC of your batteries.
With Lithium batteries the SoC can not be determined reliably by the battery voltage, so the internal battery monitor of the Multi doesn’t really work.
In case this isn’t already done: you need to connect the batteries to the GX CAN port at 500kBits/s.
They’re not officially supported but should work just fine.
Dear pwfarnell,
thank you very much for your comments. Indeed, I wasn’t aware of the surge voltage problem with contactors BUT just I looked on the spcifications of the installed contactor. It is an ABB 16-30-01-11 type, 20-60V DC and it is written in the datasheet that it HAS surge protection. Therefore I guess that I (hopefully) couldn’t have damaged the relay 1 …
I think it will be best that my Tanzanian colleague tries to test for resistance on the NO and common terminals when the relay is on and off.
Just I looked on the Victron’s menu. Is it correct if we configure like that:
settings - generator start/stop - manual start - start generator ?
If yes, I have an additional question (therefore I added the picture from the last settings-display): Isn’t it necessary that we additionally configure the 2nd line with: “run for (hh:mm)” - so to put in an arbitrary value for the time intervall? Otherwise the relay 1 wouldn’t operate, that’s correct?
And after doing that the relay 1 should shut through immediately ?
Thank you and greetings
