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Patrik Kall avatar image
Patrik Kall asked

Low Temperature cut -off, Venus/BMV/Smart sensor

I have a Raspberry Pi with Venus OS, connected via USB/VEDirect to one SmartSolar 100/30 a Phoenix C24/1600 Inverter.

I am considering a BlueSolar 150/35 for a 2nd array of panels.

I use the VRM with a 4G modem for remote monitoring.

I want to replace my AGM cells with LiFePo4 cells and need to monitor the temperature, so that I dont charge them below 5 degrees C.

Can I use a BMV-712 with a separate temperature sensor, connect the BMV to the Pi and share the temperature with both the Smart- and BlueSolar MPPTS?

Or must I buy a SmartSolar MPPT???

This is what is written about the BMV/Venus OS and Temperature:

  • Add shared temperature sense, and a switch (default on) for the feature. At present only a single configuration is supported: a BMV-702 or 712 with the temperature sensor accessory. When such a battery monitor is connected, and temperature sense is enabled, the Venus-device will send the battery temperature to the connected Solar Chargers and Inverter/chargers.

// Patrik

BMV Battery Monitortemperature
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3 Answers
klim8skeptic avatar image
klim8skeptic answered ·

Hi Patrik.

"Can I use a BMV-712 with a separate temperature sensor, connect the BMV to the Pi and share the temperature with both the Smart- and BlueSolar MPPTS?"

I have a Venus GX and can confirm that a Smart Solar and a Blue Solar will cut charging below 5c when STS is enabled in the Venus. I use a Venus/Multiplus temp sensor connected to either the Multiplus or Venus.

The BMV 712 will do the job.

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Mark avatar image
Mark answered ·

1- DVCC - STS (Shared Temperature Sense) can send battery temperature data to either a BlueSolar or a SmartSolar MPPT.

2- However, I would still highly recommend purchasing the SmartSolar model - the inbuilt Bluetooth capability is extremly helpful with configuration and direct monitoring (you won't regret it).

3- DVCC - STS capability has actually been expanded in recent Venus OS firmware updates to also accept and distribute temperature data from other sources, such as an inverter/charger or a VenusGX/CerboGX with a battery temperature sensor (not just from a BMV).

4- To ensure safe and reliable operation of a Lithium battery it is highly recommended/essential to use a dedicated BMS (Battery Management System) that measures voltages and temperature at an individual cell level and is integrated into the overall system to protect for scenarios of extreme high/low and excessive/abnormal differences between cells.

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Patrik Kall avatar image
Patrik Kall answered ·

Thanks guys,

Just what I wanted to hear.

I do have a Bluesolar 100/15 with a separate BT dongle, that I need to replace because of new panels with higher Voc.

Will reach 102V at -20 degrees C, which is not uncommon during winter in Sweden, and I dont want to disconnect the panels now and then.

So I probably can go for the BlueSolar and reuse the BT dongle, by disconnect the VE.Direct cable whenever I need to use my iPhone to connect directly.

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