Dave avatar image
Dave asked

Temperature reading from where?


Equipment installed:

1x Quattro 24/5000/120-2x100

2x SmartSolar MPPT Charger (150/85 rev2)

1x CCGX firmware v2.60

12x AGM batteries

12x PV panels

I want to capture temperature readings for the building where the equipment above is installed and since I already use Modbus to enable/disable the Quattro charger I looked for a suitable Modbus register to query. This would avoid having to get a separate sensor and could integrate with my existing scripts pretty easily.

The only obvious setting in the Modbus register list XLSX that returns anything is Modbus ID 246 Addr 61 ("Battery temperature") and since the value increases quickly by up to 7 when the batteries are being charged, I am guessing a temperature sensor is being heated by the Quattro charger which operates between 0030 and 0430 every night. There is no sensor or BMS on the batteries themselves so it is not related to the temperature of the batteries. For some reason the returned value takes much longer to drop down again once the charger is off.

The reading seems to give me what I want, so I think I am happy with it but it niggles that I don't know exactly where it comes from. Can anyone confirm that Modbus ID 246 Addr 61 is returning temperature from a sensor in the Quattro located above the charger? Or is it returning something completely different?

Many thanks,


MultiPlus Quattro Inverter ChargerModbus TCP
2 |3000

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

2 Answers
JohnC avatar image
JohnC answered ·

Hi @Dave

246 is the Quattro, and it's temp sensor looks like this:

They come free with the Quattro, and (unless thrown away) will be installed on the main battery +ve terminal. Might be hard to see, I have mine red-taped to the main batt cable and it's almost invisible.

Else follow the wires from the Quattro.

2 |3000

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

Dave avatar image
Dave answered ·

Thanks John.

Wow! So I could unwind the wire and put the sensor anywhere I want - within reason and the length of the cable?

2 |3000

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


I suppose you could. But don't forget there's a reason it's mounted on the batt terminal, to provide temp compensation to the the charge V parameters. And if set up, also to the mppt V's.

0 Likes 0 ·

If you had a Venus or Cerbo you could add an additional sensor on them. I have one monitoring ambient temperature inside my Venus enclosure. Just make sure you manually select the right sensor via DVCC for correct temperature compensated charging. The wrong sensor reading will shorten the battery lifespan EG. Freezer sensor used for Battery charging... poof!! fried batteries.

0 Likes 0 ·