Is it possible to install the temperature sensor on the negative pole?

Question

question

Christian Lindermann asked Jul 12, '20

Is it possible to install the temperature sensor on the negative pole?

Hi. Following case: I’m building a lithium battery with Thundersky cells. On the plus pole there will be the bms (ecs lipro).
For my BMV-712 I need to install the temperature sensor...so there are two points I’m not happy with.

First, the temperature sensor is quite big, so maybe I’m running out of space ;)

Second, because it is not an active balancer the bms turns power to heat, so I think the probe would not provide valid data.

So my question is, could it be a possibility to install the sensor on the negative pole and just use the black wire to the temperature input on the shut? Another wire would deliver the +12V to the shunt...

thank you for supporting me!

Yours, Christian

BMV Battery Monitor Lithium Battery Temperature Sensor

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Victron BMV battery monitors product page

Victron temperature sensor disambiguation table - which product supports which sensor

Additional resources still need to be added for this topic

Battery Compatibility

Did You Know - How to create a battery profile for non-Victron batteries?

Additional resources still need to be added for this topic

Modifications Space

Node Red Space

Answer 1 · 2020-07-13T22:54:09Z

Justin Cook answered · Jul 13, 2020 at 10:54 PM

Hi @Christian Lindermann, no, this is not possible with the BMV-702/-712 temperature sensor. That being said, why are you installing it at all if you don't believe the installation location will provide real temperature data? If it were me, I would only install a power supply wire (as provided in the BMV-712 kit) and then install a separate temperature sensor like the Smart BatterySense that physically attaches to the battery, thus providing real temperature data from the battery casing itself.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 2 · 2020-07-21T08:12:51Z

Christian Lindermann answered · Jul 21, 2020 at 08:12 AM

Hi.

Thank you for your suggestions. Well what worries me is, that the measured temperature is more the temp from the BMS instead of the real (inner) battery temp. SmartBatterySense might be an option, but it would be an additional device...especially the BMV already offers the function already.

Is there also a technical background that does not work as proposed?

Another problem I found is that the sensor has only an M8 cable lug, I need a M12 to conect it to the Winston terminal.

Greetings

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 3 · 2020-07-21T09:42:38Z

klim8skeptic answered · Jul 21, 2020 at 09:42 AM

Is there also a technical background that does not work as proposed?

The lug provides DC voltage for the temp sensing IC within the lug.

Another problem I found is that the sensor has only an M8 cable lug, I need a M12 to conect it to the Winston terminal.

I moved all my low power connections onto a short bus bar. I have not noticed my shunts getting warm.

img-20200721-1918231.jpg (551.9 KiB)

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

question