Suggestion : transmit temperature from Ve.bus smart dongle to BMV712

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Joka GIMENEZ asked Jul 31, '22

Suggestion : transmit temperature from Ve.bus smart dongle to BMV712

Hi!

Since the Ve.bus smart dongle has recently been given the Ve.smart networking capability to transmit voltage and temperature to the network, I was wondering if it could be possible for the BMV712 to receive the temperature so that it can display it?

My thought : currently the BMV712 can only either receive/display the starter battery voltage OR the temperature via the shunt B1 and B2 ports.

Thanks to the VE.bus smart dongle, now there is an other option to transmit the battery temperature to the mppts and other chargers, leaving the B2 port open on the BMV shunt for the starter battery sensor.

BUT while the temperature is now received and displayed via the app on the mppts, it would be GREAT if it could also be received and displayed on the BMV712!

Any thoughts?

BMV Battery Monitor VE.Smart Network VE.Bus Smart Dongle

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Answer 1 · 2022-07-31T16:56:04Z

johanndo answered · Jul 31, 2022 at 04:56 PM

It sounds great, but it isn't . Each device should report its OWN sensors, not gossips from other devices, otherwise you will get mad troubleshooting. Nothing wrong to read the temperature on the Quattro (where the Ve.Bus dongle belongs as sensor) if you use a sensor on the Quattro. If the BMV has no temperature sensor, it should not report a temperature. Same applies to a SOC in the Quattro, if the BMV calculates the SOC, Quattro should shut up and not report a SOC.

The BMV doesn't NEED a temperature information to work, so makes no sense to receive it, it can provide it to other devices if it has the sensor connected.

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Joka GIMENEZ commented · Aug 02, 2022 at 02:04 AM

I agree with what you said, but I believe there would be some very easy way to make everything work, if Victron decided to put the effort in.

When several devices are linked on the VE.Smart network, it wouldn't be hard to allocate them a level of priority as per the value that would be most likely to be closest to the truth.

For example, it is commonly admitted that the BMV shunt is close to the batteries and has the best voltage value.

Therefore it would make sense to give priority to the voltage value given by the BMV and ignore any other value.

Only thing i disagree with you is your statement that it "makes no sense" for the BMV to not receive the temperature.

Yes it doesn't need it... but it is a display! And it already comes with the capability of displaying the temperature. So why not do it? I am not talking about the temperature inside the quattro, but the temperature monitored by the sensor that goes on the positive terminal of the battery. It is actually EXACTLY the same as the one used for the BMV, just connected into an other device. The info collected should therefore exactly the same as the BMv? Or am i missing something?

And if this temperature is good enough to be transmitted to my mppts to adjust charge voltage (which is the case right now), i would assume it would be good enough for me to quickly look at on the display?

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Answer 2 · 2022-08-02T04:30:22Z

johanndo answered · Aug 02, 2022 at 04:30 AM

If you want it on the BMV, attach it to the BMV. You always can see it on the App anyway or on the Cerbo. The BMV is not a universal display module, it does not gather data from other devices, the Cerbo is one for this purposes.

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