Hello, Happy Holidays. I do have 3 x Multiplus 5k in parallel and singlephase. The issue is that when i’m modifying AC input current limit with MK3 and Vbus, the new value is saved in Master Multiplus only, but for the other 2 slaves do not change( even if i send to all devices). But if i modify it individually per each slave unit, is working. Is it this a bug or a feature? Secondly, i’ve set for each unit 15A AC input limit, but if I check VRM, i do have a different value for the input AC current of 34A. Now, even if I change in VRM the value, the reading with MK3 for each unit remain unchanged 15A. Are these 2 methods(MK3 vs VRM) refering to different AC input parameter? Thanks
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It is designed to be used with a GX which then interfaces with all the inverters and changes all to the chosen setting per phase
Otherwise, yes you do have to manually modify each individual inverter.
Since you mention vrm then yes you have a gx and missed the piece on the manual about this very issue.
The following settings need to be made in the master of each phase:
Inverter output voltage
Input current limits
(the effective input current limit is the limit set on the master multiplied by the number of units per phase. For example, setting a 10A limit with VEConfigure in a system with two units per phase results on a 20A limit for that phase. Being able to set a different limit per phase allows for maximum configurability.
Thanks!
When i’m trying to modify in VRM the grid current limit for Multiplus, it seems that only the master unit is updating with the new value i’ve set/3 ( ex. 9A in VRM, the master unit takes 3A) while the rest of slave units current remain unchanged. I’ve checked this behaviour with MK3 and it seems strange to me. I would expect each unit current value i set/3. The overule is activated for each unit.
Is their current sharing right though? Balancing parallel set ups can be tricky. There are many posts on both this forum and the old one about it.
Not sure that i would worry about the written values in the units themselves. What is the logging showing?
Clear on logs
All firmware is the same/up to date etc?
It is odd they are not changing if overruled by remote is on and load sharing (wiring balance) is right.
Yes, I have installed the latest FW revision for Multiplus : v552.
It likely will be down to cable dimensioning and installation circumstances. Resistance is the key.
There is more theory and examples in the manual.
There is not much more that can be done over the internet.
A side effect of over dimensioning the AC cabling can be faulty Power Assist operation. Out of all units, the phase master is in control and measuring the AC input current. And in case that current is (grossly) unevenly distributed between the paralleled units, the resulting total AC input current can end up being too low (under charging the battery).
The current is measured by the master. If there is more or less resistance to the two follwers then you will get imbalances.
By the way, power assist is disabled in my case, I don’t know if is having any influence here.My worry in the end is not about current distribution(my system is anyway oversized), but why parameters are not sent to the slave units as well no matter the method.
Not likely. In 99.95% of all cases i have seen on parrallel sharing it is the wiring. That is one of the reasons why it is annunsupoorted wet up if you have not had alot of electrical and solar installation experience.
The slaves follow the master, so the settings not changing is not a concern here.
Do they load share equally while Inverting? What step have you taken to diagnose and test and measure current sharing in both the ac and dc wiring?
Thanks, understood, I will do further measurements and investigations.
I’ve discussed the topic with different experts and seems that this behaviour is perfectly normal. By updating ac in current value in VRM, only master unit will show the change, while slaves will follow it BUT without reflecting new values locally.
Yes. That is why i was saying not to be concerned with the settings.
But be concerned with the wiring and current sharing.
When you parralle any multiplus or quattro units, including multiplus or quattro II units.
The only unit that needs updating in regards to these settings is the master unit. All the parralled units follow the masters settings ONLY. Also the charger voltages etc as well. They all follow the masters configuration. So there is thus no need to modify any of slave units.
If there was a need to update them then they would have been updated.
There is no harm if you do change them, but there is no effect if you do.
Note this as always been the case
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