I’ve gotten this system, and now I need some help setting this up. Seems like no matter what I do, I can’t get it just as I want it
I have MultiPlus-II 48/3000/35-32 and the SmartShunt 500A. Battery bank, solar panels and generator connected to grid input. A DC system via a DC-DC converter connectet to the shunt.
What I want to accomplish:
Always be shown the battery state of charge no matter if it’s the solar charger, grid charger or usage from inverter or the extra DC system.
When I took over the system, the shunt was connected between battery and MultiPlus. The DC system was tapped into this after the shunt, parallell with the MultiPlus. Shunt was configured as batterymonitor, only connected by bluetooth to the MultiPlus.
Then it did not meassure the DC consumption?
Changed configuration and connection so the shunt only meassures the DC system. But then the MultiPlus battery monitor does not see the solar charging and fail to update the SoC accordingly? Only DC and inverter consumption and charge from grid (generator).
How to connect and set this up so I can have a battery monitor overseeing the full system? How to connect and set parameters? Do I need more equipment?
I would agreee with you. But when connected like that the system did not use the DC load as a part of SoC, system would show the battery as fuller than it was.
The DC usage isn’t meassured either. Attached log of DC usage when configured as battery monitor first and then energy meter. You clearly see that the measurements are only guestimates and total rubbish at the left part before changing from monitor to meter, throwing every single start of the fridge as both huge loads and also enormous backfeed to the DC bus.
I’m looking for the solution to have SoC calculated correctly when there is a DC load in addition.
See this diagram, if you have a DC load drawing power from the it will be measured. Everything flowing into or out of the battery is measured. You may not have all these devices.
If you have the shunt wired as shown and set as battery monitor the SOC will be accurate. The DC loads calc will be an estimate. If you want accurate SOC and accurate DC loads you need 2 shunts, one battery monitor and one energy meter set as DC system. See
Perfect. This confirms my suspicion of wild calculations. Thanks. I got the impression the MultiPlus had a battery monitor as well, making a setup with only one shunt possible.
So… If I want accurate meassurements of the DC load, I need another shunt for this.
BUT, how is that one connected to the rest so I get hold of the data?
Should the shunt I already have only be connected in the wireless network? And the new one via ve.direct cable? How will the setup in the menus be? Trying to make sure I get hold of all components necessary before my next trip to the cabin.
The multiplus has a battery monitor, but if you have solar, other DC chargers or DC loads it does not know about these so it is not accurate. Do you have a GX device or a raspberry pi running Venus OS. When this is known how to connect the other shunt can be advised.
I have the MultiPlus-II GX. It has solar and grid charger in the box, no extra DC charger. I have a DC system in addition to the inverter side. I want to have reliable SoC and also meassure of DC usage. not the calculated with crazy values. I guess the GX is the one running Venus, failed to mention the “GX” earlier. There is ve.direct and other ports inside. I have connection by Mqtt to HomeAssistant for control. No problem programming an esp if that can give any benefits.
If you have a Multiplus GX then both the battery monitor shunt and DC system shunt should be connected by VE Direct cables. Do not use VE Smart Network and VE Direct at the same time, you can get inconsistent results. You can not add a DC system meter to a VE Smart Network
As I’ve understood, the solar part is connected in that smart network. But that is ok? The shunt was also wireless, but when I changed the cabling, I connected it by ve.direct to get a connection. But if I add a second shunt for the DC system, where to connect it? There is only one ve.direct port.
I’ve been doing some research parallel here. Monitoring the DC system is mostly for fun/follow up. Started thinking about it since I got the impression that consumption was not considered for SoC. But you say it is. And it seems logical. Looks overly complicated and of no value to use another Smart shunt for this. My goal is to have an accurate SoC, and that will be accomplished with the smart shunt I already have? Should this still be connected by ve.direct or revert back to the wireless network?
For measuring the DC system separately, it seems like the easiest and cheapest option then is to just use a shunt and read the values into Home assistant by an esp. Parts I already have
You are correct, it is not necessary, the only time it is useful is if you have DVCC controlling chargers on a managed battery, having DC loads measured means that DVCC can add these on to the target current for the chargers.
I went back changing the connections today. Kept the ve.direct cable.
Too bad the DC readings are crap. When inverter on values are 20W too low, fluctuating and showing also negative values. Next will be connecting a shunt with an esp32 to get those readings correct as well. Thanks for your help!
