Under steady sun, when inverter load increases, the PV voltage on the two 100/30 controllers drops immediately and total solar production decreases
When inverter load is removed, the PV voltage immediately recovers and available solar power increases again.
I have 2 170w panels in series on each 100/30.
I have 1 220w panel on one 100/20
The 100/20 works fine, each of the 100/30 controllers will drop the pv voltage from 40ish volts to 18- 21 slowly on large multiplus 2 loads. Remove the load and the pv voltage returns. The current pretty much stays the same. I’ve swapped the series 170w panels over to the 100/20 and they will work fine on that controlle. They only do it on both 100/30 controllers
System:
MultiPlus-II
Cerbo GX
SmartSolar MPPTs:
2 × 100/30 each with 2 series 170w panels
1 × 100/20 1 220w panel
~900W PV total
LiFePO4 battery bank
DVCC enabled
I keep trying different tests always same result until I swapped to the 100/20
It’s all brand new. I even took the fusing off the 100/30’s to eliminate that possibility and put their outputs closer to the batteries on a different buss
I was going to start blaming the panels, until I swapped to the 100/20 controller with one of the strings .
Both 100/30’s act the same way, within a few volts. I don’t know what the common denominator is. .
VE.smart is not intended to be used in larger installations, and since you are using a Cerbo and DVCC as well, theres no benefit. Whenever a value is available over VE.direct from the Cerbo, then its counterpart that comes over VE.smart should be ignored but its worth a try.
But i dont see a Shunt mentioned or that the batteries BMS is communicating with the Cerbo. So theres no voltage reference for the VE.smart network, which means that one of the three MPPTs will be chosen to be the voltage master. Which BMS is chosen to be the controlling one in DVCC? If theres no Shunt and no BMS coms then it will be “None”, so essentially disabling DVCC
I think there are shodows at the modules. If there is a shadow only on one of the cells, the PV voltage breakes together. Olso if one module looks to east and the other to west.
PV Voltage is whatever the optimal powerpoint of the panel is at the time, nothing you can directly control. However in the two screenshots above, the battery voltage is vastly different, 13.4V and 12.8V which is a lot. If that voltage is being sent over VE.smart from the 100/20 (since that one is not acting up i guess it was chosen to be voltage master) then that could be part of the issue. Also if DVCC is running but has no valid BMS assigned, then i have no idea how its going to regulate charge current and voltage
I’m no master at this. But my junior brain thinks if the system wants more power and I have full overhead sun then the MPPT’s should be giving as much power as they can, and all I see is a decline in solar output from the two 100/30’s and not on the 100/20 until the inverter is done. It’s like a light switch… on is bad power , off is good power.
Theres no point switching VE.direct ports, but there is in removing the VE.smart network.
Is the DC load figure stable or does it change with power output of the MPPTs? If it changes then one or more MPPTs are connected to the wrong side of the shunt.
IS the BMV selected as the controlling BMS in DVCC? What else did you set in DVCC?
I can have the multiplus inverting 1300w with a 250w DC load and the PV watts drops. Turn off the inverter and leave the 250 DC watts Pv watts will come back to, what I would assume, normal
In that scenario above inverter on, I can watch the PV watts go down 250w …turn off inverter 250w comes back up
All the grounds, along with the working 100/20, land on the lynx then go to the shunt
An update… I’ve taken this as bare bones as I can, I think.
One 100/30 with one of my panel strings, and the 100/20 with the other identical panel strings.nothing else, ve networking turned off on everything, turned off on BMV712 as well.
100/20 holds the voltage 38 ish , the 109/30 drops all the way to 18v
No shading, full overhead sun the panels are getting the exact same sun
Means VE.smart? Does it do the same if you remove VE.direct? Then theres truly nothing left that would influence the MPPT from the outside control wise
Nothing in terms of firmware or software control, maybe there is a dc ripple component here that is causing an issue.
Its not there when the inverter is off, it is there when it is on.
I don’t know how it is wired physically. I have seen DC ripple affect mppts. And in lower voltage systems it is usually worse. So it was just a thought.
Ideally the smart network is not used when there is a GX device in the system. It is mentioned in the smart network manual.
You want the GX to be the only system co ordinator. Everything is connected there and uses DVCC.
Mixing the two connection methods is a definite known issue to cause weird behaviours
Ok. Thanks for the reply..for my testing going forward I will leave this off.
It was left on because I had all the chargers and panels set up 6 months BEFORE I went full Victron with the Multiplus and Cerbo. I’ve just been hooked up with this system for a month now, and my first trip out with this system, this was the behaviour I found.
Solution>>> bought 2 new 150/35, took out the 100/30s
Problem gone. Nothing to do with settings, cerbo, wiring, Dvcc, Batteries, buses or ripple
It was clearly the 100/30s
I found a thread from a year ago describing the same problem on their 100/50..I conclude it is the 100/50 and 30 family…not the 100/20 and 15
I’m also seeing opinions from other users that claim they don’t have a problem, but everytime they have 24volt systems
Anyway here is the proof that I have
The listed controllers are 100/20 then 100/30 then (new) 150/35
Just sucks I had to spend my own money on this and Victron won’t reply
