I am running the venus-os_dbus-serialbattery to manage the charge in my lithium bank and that part works quite well for me.
I also have 2x 5 Kw multiplus inverters but prefer not to run then in parallel all the time. So I got the idea from Andy from off-grid garage to use the second inverter as a generator to support the first generator when the loads exceed 4400 kw.
This may happen once or twice during day time if there is enough solar available.
It actually works quite well and the second inverter is in standby for 90% of the time.
Here is where I am currently getting stuck , the two inverters are sharing the same battery , here is the setup
if the second inverter gets activated ,there is an additional dc load
the DVCC from the serial bms is all over the place.
It seems like the system does not pickup the extra DC load from the second inverter and therefor the MPPT’s does not charge the bank anymore.
I added a smart shunt as a dc load but the system is still not “happy”.
Any ideas of what I may be missing here?
Configure the shunt as a DC system instead of a DC load.
The idea is that in a system with DC loads, the combination of all of them is measured by a shunt configured as “DC system”.
“DC load” is when you want to measure a specific item and have data for it on VRM, or want to display it separately in the DC loads breakdown in the new GUI. Nothing special is done with DC loads (since we don’t know how they might be connected).
May I ask, apart from because you can, why do you prefer not running them in parallel?
I get why Andy did it which was brilliant BTW, he had a different size Multi and Phoenix.
Must say back when I first saw him pull the stunt, my brain was broken for a day or 2 in trying to get my head around it.
How did this all work out long term - I was thinking of trying the same thing.
Then the new 6.5 kW Multiplus II was released - seems it’s just easier and less hassle to not use the Multiplus II 5000/70/48 in any sort of parallel setup - even Victron frown on Paralleled setups - too complex and setting them up right takes a lot of Victron knowledge.
But if I couldn’t my hands on a 6.5kW Victrom MPII, then what you have mentioned and you have tried would be the way to go, so interested in this.
Running now for three month it does exactly what wanted it to do. If the load is > 4000w , the secondary Inver gets switched on the primary supports the load and then once the load drop to < 3000w for 10 min it will switch off the secondary inverter.
Only thing I has to add was a smart shut so that the system knows of the additional DC load else it would mess around with the charging during the day.
Very happy with the setup
when you say “switch off” do you mean it goes completely dead with no power to it or it goes to standby mode ? - reason is the standby power draw is quite a lot over 24 hours.
Very very interesting though - glad someone here has done this as it means it is possible and does work.
There is a setting in the older Multiplus where you place it in emergency mode or that is what I think it is called. ( All the LED’s flicker )
I have read the newer Multiplus can be switched of remotely
In this mode it uses just about nothing , this is what the smart shunt register
!