Trying to understand overlap & differences between Smart Shunt, BMS, & Victron 100/30 MPPT

[zarguy]

Newbie here. I'm adding solar panels to my van. I'm trying to learn as much as I can before I spend money on components.

I bought 2 Newpowa 220 watt solar panels, Victron SmartSolar MPPT 100/30 charge controller (with Bluetooth). I'm planning on getting two 12V 100ah batteries. I know the charge controller has to know a lot about the state of the battery (ies) to charge it (them) efficiently. I've been reading about the need for a shunt to get real-time & historical battery data.

What data does a shunt report that the charge controller doesn't? Vice-versa?
likewise, does the BMS share any data with the shunt or controller?

Do I need a separate shunt for each battery? If I have just one shunt on one battery, can it read & report data for both (or more) batteries?

If the battery lacks Bluetooth, will adding a smart shunt & Victron app access the same data as if the batt.ery had Bluetooth? If the smart shunt & Victron app replicate the features of the battery's own Bluetooth, I could save money on the batteries & put that towards a shunt.

I've been reading a lot about these components, but no one seems to discuss how they interact or overlap.

Thanks in advance.

 

[Rocketman]

With Victron, you will want one shunt - either the Smartshunt or BMV712. The difference is the BMV712 has an old school display and costs a little more.

You will connect your two batteries together then the negative will go to the shunt (battery side), then ALL (everything else) goes on the load side of the shunt - loads, inverter, mppt, chargers, etc.

The Smartshunt/BMV712 can setup a Bluetooth communication to the mppt to pass along voltage and current (and battery temp if you buy an optional temp sensor).

There will be no bms communication to your Victron stuff at this level (there can be but it is often not done in Van sized systems (costs lots more).

Be sure and buy batteries that have Bluetooth communications. Often on this site I answer questions when the batteries are acting weird (cutoff, etc), I tell them it sounds like your cells are out of balance- do you have Bluetooth to verify? The Bluetooth will also tell them when they have fixed the out of balance issues. Without communications it is all guesses - so spend the extra few bucks and get Bluetooth communications - all you need to see is each cell’s voltage.

At your level the battery communications don’t interact with the Victron data.

Will you be having a Victron inverter - like Multiplus 12/2000? If so there is more to discuss.

Did I answer your questions? (Or did I miss something?)

 

[LakeHouse]

I know the charge controller has to know a lot about the state of the battery (ies) to charge it (them) efficiently.

Not really. It just needs to know Voltage, and it can measure that itself.
If there’s a shunt and a cerbo (or VRM on a Raspberry Pi), then the shunt can give a little better measurement of the voltage, nice but not necessary.

What data does a shunt report that the charge controller doesn't? Vice-versa?

The shunt tracks battery state of charge, which the SCC knows nothing about, except at the high end when voltage rises.

Do I need a separate shunt for each battery? If I have just one shunt on one battery, can it read & report data for both (or more) batteries?

You only need one shunt, and it will track combined SoC for the batteries, but it won’t tell you what individual batteries are at. In most cases combined SoC is all you need.

f the battery lacks Bluetooth, will adding a smart shunt & Victron app access the same data as if the batt.ery had Bluetooth

No, you won’t get individual cell voltages.

 

[KnobCountry]

Don't skip the Bluetooth. You'll regret it later if you do.

 

[grizzzman]

The smart shunt ( through Bluetooth ) will show true battery voltage to the charge controller this allows the charge controller to increase voltage ( to a point ) to compensate for voltage drop, additionally it will report battery temperature to the charge controller to shut down charging at a preset temperature.

 

[Boomerweps]

IMO, a seperate shunt is like a gas gauge. Good information, but not always required for every system, especially small to mid size mobile systems. The bulk of its functions can be tracked by alternate means. I did add a shunt to my system but rarely look at it. I often check my 4 individual batteries with Bluetooth. On a home system, a shunt would be more useful for overall data tracking of electrical use. I don’t consider a shunt cost effective for my 400AH RV system

 

[mikefitz]

charge controller has to know a lot about the state of the battery (ies) to charge it (them) efficiently

Basically the charger needs to be connected to the battery so it can measure battery volts over the connecting cables. The Smart charger displays over the app, panel volts, current, battery volts and current generated by solar into the battery. If also has graphical display and records the last 30 days of solar charging history. No other component is needed for this.

An option in the system is the Victron smart shunt or BMV 712. This displays battery SOC and records all power into and out of the battery. Regard this as a kind of battery 'fuel gauge'.
Since the shunt is normally mounted close to the batteries it can report battery volts and temperature to the Smart Solar coltroller.
This reporting is optional, the solar controller functions OK on its own, with one exception. If you need low lemperature charge disable , then either Victron shunt with optional temperature sensor or Victron Battery Sence module, these report temperature to the controller. (Note the Victron battery Sence module is a much lower cost than the Shunt)

will adding a smart shunt & Victron app access the same data as if the batt.ery had Bluetooth

Not quite, a BMS with Bluetooth will have similar data, volts, amps, SOC, to the shunt , but in addition, cell status and battery protection history, also the option of modifying protection limits in the battery.
Having both Bluetooth battery and Victron shunt is ideal, but if cost is a factor, having Bluetooth batteries and loosing the Victron shunt would be prefered.

BMS share any data with the shunt or controller?

No, not normally. The BMS and the Victron shunt/ controller, in a modest set up, are independent systems.

Conclusion.
Suggest,
Basic system
Batteries with Bluetooth ( these batteries should have low temperature protection, thus avoiding the need to have Shunt/ Battery Protect reporting temperature to controller), consider a 200 Ah or slightly higher capacity battery rather than two is parallel, assuming a 12v system
Victron smart solar controller.

At a later stage add the Victron Smart shunt if you feel its features are important.