Victron BMV 712

[Tonyyoknee]

I apologize if this question has been asked multiple times in advance.
I have a 2023 flagstaff 19 BH E Pro, and would like to utilize a smarter battery monitor than what is in the trailer. In looking on where the shunt placement goes between the battery negative post and all other loads. I see that my negative load side on the trailer is traced back to the inverter.

When the shunt is in place it only will show battery voltage and % charge on the app and the small monitor screeen. With it not connected to shore power and inverter is turned on I get current, power, consumed Ah and Time remaining.

If I shut off the inverter I only get battery voltage and %. Is my (-) load side incorrect? and not the inverter? Is it behind / near the converter.

Moved battery bank inside next to inverter (-) load

 

[jlankford]

In the photo I see more than one wire connected to the negative side of your battery bank. ALL of the current needs to flow through the shunt monitor, which means all of the negative side cables from all devices, etc. need to be connected to the negative loads side of the shunt and NOT to the battery. Only one cable, from the shunt, should be connected to the battery negative.

In the pictured configuration, depending on switch settings, etc. there can be a dead short across the shunt, which would explain why it's measuring zero voltage sometimes.

 

[Tonyyoknee]

712 BMV shunt

Since my battery bank is (2) batteries in parallel, it would seem impossible to have only one cable on my negative battery terminals. I understand not stacking on the shunt side, should I move my battery ground to the 2nd battery (-) terminal? The voltage does show up, on my app, and the small monitor screen just not current, power, consumed Ah, and time remaining
In general I think I can monitor loads through my inverter only, which wasn’t necessarily why I bought the smart shunt. I guess I misunderstood where DC loads are terminated, definitely not where I placed it inline with the inverter.
Pictures of usage with inverter off and inverter on (Not connected to shore power)

Thanks for replying

 

[jlankford]

Since my battery bank is (2) batteries in parallel, it would seem impossible to have only one cable on my negative battery terminals. I understand not stacking on the shunt side, should I move my battery ground to the 2nd battery (-) terminal? The voltage does show up, on my app, and the small monitor screen just not current, power, consumed Ah, and time remaining
In general I think I can monitor loads through my inverter only, which wasn’t necessarily why I bought the smart shunt. I guess I misunderstood where DC loads are terminated, definitely not where I placed it inline with the inverter.
Pictures of usage with inverter off and inverter on (Not connected to shore power)

Thanks for replying

I do not include the jumpers which form your battery bank in my statement that you should only have a single connection to the negative side of the batteries. Move the cable which has a red crimp lug to the shunt on the side where the "negative loads" cable is connected to the shunt.

 

[dalford]

I do not include the jumpers which form your battery bank in my statement that you should only have a single connection to the negative side of the batteries. Move the cable which has a red crimp lug to the shunt on the side where the "negative loads" cable is connected to the shunt.

X2.. only one wire to negative side of battery. All other neg wire(s) need to hook to the other side of the shunt. In your case the negative wire to the inverter and the negative to all your other dc devices.

 

[jlankford]

Here's a comparable photo of my system. The shunt is at the upper right. Note that there are multiple positive cables connected to the positive battery terminal, and multiple negative cables connected to the load side of the shunt.

 

[Tonyyoknee]

OK thanks, I will try that and will give update tomorrow

Regards,

Tony

 

[Capacitor]

Here's a comparable photo of my system. The shunt is at the upper right. Note that there are multiple positive cables connected to the positive battery terminal, and multiple negative cables connected to the load side of the shunt.

Wow, you have some straps there. Do you do a lot of 4 wheelin and jumps?

 

[Tonyyoknee]

Here's a comparable photo of my system. The shunt is at the upper right. Note that there are multiple positive cables connected to the positive battery terminal, and multiple negative cables connected to the load side of the shunt.

The (-) cable going into the load side of the shunt, is that your inverter cable, or other loads…do you include your inverter in the negative load side? It seems that my shunt only looks at the inverter currents, and .I am curious if I have mine hooked up incorrectly? Not sure if I have included all my DC loads.

 

[dalford]

The (-) cable going into the load side of the shunt, is that your inverter cable, or other loads…do you include your inverter in the negative load side? It seems that my shunt only looks at the inverter currents, and .I am curious if I have mine hooked up incorrectly? Not sure if I have included all my DC loads.

All the return loads (-) must go THRU the shunt. That includes the inverter. The inverter draws current from the + side of the battery and the return current from the inverter must pass THRU the shunt then to the - side of the battery so you can measure the draw from the inverter.

There should only be 1 wire returning to the neg pole of your battery. That is the output side of the shunt. There will be at least 2 wires (with inverter) to the input side of the shunt.

 

[Aussieguy]

The shunt measures battery capacity ….. that’s it only job
Counts the electrons as they are used

The inverter is a user of battery electrons
So the electron the inverter uses……. need to be counted too
Otherwise you will get false reading from the counting circuit
You will be missing battery capacity if you don’t count the electrons properly

Move the cable with the RED lug … as mentioned in post 3
Then all loads will be going through the shunt
Inverter IS a load

Addition
Solar charger or converter or any other charging source
Is also to be on the load side of the shunt
Shunt sees them an will know it is a charging current and count them as such
2amps used by loads
Plus 5 amps in from charger
Equals 3 amp is going into battery … charging

20 amps used by inverter
Plus 15 amps going into the battery from Solar and or converter
Equals 5 amp is being removed from battery

 

[jlankford]

Wow, you have some straps there. Do you do a lot of 4 wheelin and jumps?

These are just basic 1" cam straps.
https://www.nrs.com/nrs-1-color-coded-tie-down-straps/p4bc

The batteries are sitting under a bed - there's no box to constrain their movement. Why is securing them a surprise?

 

[jlankford]

The (-) cable going into the load side of the shunt, is that your inverter cable, or other loads…do you include your inverter in the negative load side? It seems that my shunt only looks at the inverter currents, and .I am curious if I have mine hooked up incorrectly? Not sure if I have included all my DC loads.

Yes, the inverter (-) and all other negative cables for both loads and charging sources connect to the load side of the shunt.
The shunt measures current flow in either direction - in or out. It doesn't actually know anything about your battery's state of charge (SoC). It calculates the SoC by measuring current in and out and calculating the SoC. It can only calculate an accurate result if it sees all the current flowing in or out of the battery.

Note that you need to follow the shunt's setup instructions and set a reference point by fully charging your battery to a known 100% SoC and then tell the shunt that's the full point. The SoC calculations the shunt is doing are meaningless until you set that reference point. If you already did this, you should do it again after you fix the connections.

 

[Tonyyoknee]

Yes, the inverter (-) and all other negative cables for both loads and charging sources connect to the load side of the shunt.
The shunt measures current flow in either direction - in or out. It doesn't actually know anything about your battery's state of charge (SoC). It calculates the SoC by measuring current in and out and calculating the SoC. It can only calculate an accurate result if it sees all the current flowing in or out of the battery.

Note that you need to follow the shunt's setup instructions and set a reference point by fully charging your battery to a known 100% SoC and then tell the shunt that's the full point. The SoC calculations the shunt is doing are meaningless until you set that reference point. If you already did this, you should do it again after you fix the connections.

Thanks for checking out my wiring, I moved the trailer ground to the load side of shunt, and (-) battery shunt to the second battery (-) terminal to separate (+) and (-)on the same battery. Success, I thought I followed directions but obviously I did not think of the ground wire. Much appreciated to all the patience and help…the Victron technician was sent the same picture, but did not catch my mistake.

Regards!

 

[jlankford]

Thanks for making the follow up post. Glad you got it sorted out.