I have a multiplus II and 4 solar chargers. The DVCC setting “Maximum charge current” is set on th Multiplus to for example 57A but the charging kept going and even exceeded 160A.
I’m I missing something ?
Why doesn’t the multiplus throttel down the solar charge controllers ?
lead acid or lithium batteries and if lithium are these with a communicating BMS or unconnected BMS.
Are you exporting power? That parameter is documented as being ignored if feed-in is enabled.
What Nick said.
If you enable DC-Coupled PV feed in, the DVCC charge current is ignored.
Ok found it in the manual The reasoning 'This is to get maximum output from the solar panels for export." doesn’t look correct. Once the export is at its limit, it shouldn’t overload the batteries.
Is there somewhere a parameter I can use to limit the current from all the inverters to the battery ?
What batteries do you have?
Exporting uses overvoltage to work, there are many topics on this subject. For supported batteries the system does not tend to behave like this, for DIY and unsupported batteries, where there are custom BMS profiles, you can have a problem.
The BMS from the batteries are not connected to GX or multiplus but every battery has a victron shunt. Battery monitor is set to the multiplus so I expectedt the Multiplus + GX would control the power from an to the batteries and also control the solar inverters.
Not in that scenario, no.
The wording is poor. To say the least. And no warning whatsoever when you change that setting. Any if the two involved. Maybe it should become hidden. Like other settings when you disable them.
I personally don’t understand why Victron even has to ignore a setting…that is used specifically to limit the charge current for batteries. What has that got to do with limiting solar export to the grid? Two different kind of animals.
Sure. A managed battery would have prevented the excessive charge current. But more importantly. Why ignore the current limit setting when it charges the battery? With excess that can’t be exported.
Perhaps this way was easier to implement, but it sucks.
Hi @ChiefSolar @rns
There is work underway to improve this situation from Victron’s end.
In the meantime there is also another solution that was developed by a Victron distributor using node red that he reports works perfectly.
This won’t help the problem, is he is already at the export limit and excess is going into the battery. The only option is to start shutting down inverters / solar charge controllers. It would be easy to write a flow to disable a MPPT if it’s a Victron charge controller, but he also mentions he has solar inverters.
Hi Guy,
Thank you for the update. Yeah I’ve also used a similar hack, and it works. As a work around. But. Waiting for the day that we won’t have to explain people anymore how things work. Even nicer without Node-RED implementations because honestly. Sometimes it feels like reinventing stuff. Haha.
Hi,
I will also upload a version that when you reach the maximum export limit will dynamically reduce the current on each MPPT but this involves a custom flow. This flow must be modified depending on the number of MPPTs.
Hi all, thanks for all the nice feedback. Looking forward to see what the victron solution will be.
I was preparing home assistant node red to indeed disable the victron solar chargers one by one.
I couldn’t find a modbus setting to limit charge current per solar charger or am I overlooking something ?
I’m interested in the node red flow mentioned here above. Can they be shared ?
I had two situations where the charge current ot the batteries was higher then I wanted.
First scenario
cloudy day with lots of sun. My north facing panels did great in this situation making that I was exporting 5Kwh (the limit I put in my multiplus) but still so much production I exceeded the 130A to the battery. This was the first time I saw this and was surprised the Victron didn’t start limiting.
cloudy day but went from full shade to full sun. The multiplus at that moment needs time to start exporting and dumps it into the battery before it reached the 5Kwh limit again for the export. Saw pieks of 200A to the battery.
None of the situations were a safety issue but were exceeding the thresholds I set to be just safe.
I have two batteries in parallel fused at 160A so still had some limit but my threshold of 130 A max charge current was there just to be able to disconnect a battery without exceeding limits.
You will have to install the node red large image and use node red on the gx device. I dont really have a full system I can test to see how this code works but I put some code together using the one in the link. I can adjust the solar controlers current based on the export power. It will also be overridden by the DVCC setting. This should get you started if you need anymore help let me know.
ADJUST MPPT CURRENT.txt (20.1 KB)
The JSON code is in the text file, just download it. The MPPT current adjust is a custom node.
Thanks a lot.
I do have venus OS large but want to use node red on home assistant since I have there a full view on car charger, grid consumption/feed in, …
I calculate and set the “grid setpoint” to my needs (force discharge battery, force grid feed in to compensate phase 2 and 3 consumption, …
In your flow you set the bluesolar charge current limit. This is exactly what I need but I can’t find this in the modbus registers. Do I miss something. Register 791 looks to have the option to activate voltage current limit '0=Off;1=Voltage/current limited;2=MPPT active;255=Not available
) At least it looks that it reports the status of the mppt but I just can’t find what the register would be to activate current limit and set the value of the current limit.
No, it’s a custom node that yellow one. When you use it, you get this warning.
Note that there is no guarantee that used services and paths will remain existent with firmware updates for custom nodes.
You can run this flow next to any other automation. All it does is reduce the solar charger current based on grid export. You will need to modify the math for your system. It also follows DVCC so if you set DVCC to 50 the controller is set to 50. If you have 4 controllers, you might need to divide the output by 4 and send it to all controllers.
I designed my system a little differently with a mix of AC inverters and DC chargers. I have east and west arrays on the MPPT and set up exports in the morning if the SOC is too high, and the battery will be filled by lunchtime. I also have dump loads and another separate 2 ESS on the same phase that soak up any solar that is above the export limit. To test this, I would have to turn off a lot of automation.
hI,
The flow and the calculation was clear and I will indeed need to calculate based on my setup. I also have mico inverters on AC out 1 so that is load I can’t control but they are below the max power of the multiplus (factor 1).
I just don’t know how to reproduce your flow to modbus settings of the mppt. I don’t see a max current parameter or so. Based on your flow it looks like there is such a parameter.
The function takes precedence of what DVCC is. If you can set DVCC in HA then use Node-Red to adjust the MPPT current. You probabbly dont need all the math and export measurement in Node-Red just to do the math in HA and set DVCC to where you need it.