question

adam-michaud avatar image
adam-michaud asked

Lithium battery protect settings

I've got 2. 24v 200ah victron energy li smart batteries wired in parallel to the multiplus 24 3000 with a ve bus BMS

Do the internal temperature sensors in the smart batteries report to the BMS for low temperature and high temperature shut down? Or do I have to buy and install an external temperature sensor and hook it to something

I also have a victron energy 220 battery protect wired into my DC loads and connected to the BMS do I need to program low voltage cut out into the battery protect if so what is a safe voltage? Or should I leave it as it came from the factory and just let the BMS shut it off?

Battery Protect
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2 Answers
ur12vman avatar image
ur12vman answered ·

yes, the BMS talks to the temp sensors in the Smart LiFePo4 batteries and will inhibit charging if the temp gets too high, as well if the temp gets below 5C (41F). The battery protect has a setting for Li batteries, make that setting and it will set the rest of the on/off settings. See pic. You didn't mention which BP you had, this is from the manual of the 12/24 65-100-200 page 1. see setting C in the programming table


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Jonathan avatar image
Jonathan answered ·

Not an answer but further comment/information. I recently discovered similar and significant temperature differences between the added smartshunt “battery temperature” and my electrical cabinet ambient temperature (in which electrical components are installed) compared to the Victron Lithium battery temperature via VictronConnect. My van install is connected to shore power 24/7 during winter while not in use to run a small 120V space heater to keep the van water system from freezing and to keep lithium ion batteries above 5C to allow for charging.

A few observations…

Firstly the ambient cabinet temperature and the smartshunt battery temperature are consistently nearly the same. In comparison, the battery temperature reading from VictronConnect can read as much as 20-25F higher. Eg 40F vs 62F

It makes sense to me that the battery temperature via VictronConnect is measuring the internal battery temperature. Eg the cells. And that the temperature is higher being connected to shore power via multiplus and the batteries are in operation supporting very small 12V loads and will, on occasion, go through a charging cycle.

Although the smartshunt battery temperature monitor is connected to the battery post, and given the very similar reading to the cabinet ambient temperature, I thinks it is safe to conclude that smartshunt battery temperature would be more accurately be described as the external battery temperature.

when not connected to shore power and the system not operating in this quasi storage/shore mode, I wouldn’t expect as large of temperature difference.

If anyone has a different opinion, please respond.

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