Hello,
Is it possible to calibrate the temperature sensors on the CellMate K9?
The reason I ask is that my batteries are in a cellar, underground where the temperature never goes below freezing. Right now the environment temperature is around +2.5 Celsius there but the Batrium software show that the minimum temp is -2 Celsius and the maximum is -1 Celsius. I believe the Batrium sensors show too low values.
Hi osaether,
We are planning to add this to our software in the future, alongside K9 cell voltage calibration, but it is not at the top of our list, for a few reasons:
Our thermistors (like most of them) are only accurate to ±5C. We have structured our curve conservatively to make sure the battery does not charge below zero, which has the effect of stopping few degrees above zero.
If you like, you can modify the thresholds on the Control > Charging tab, but I suggest instead to heat your batteries instead. This is why we offer a Heating Required option in the Hardware > Expansion tab. You can also harvest heat from your inverter if you are short on sun.
You don’t have to look far to find datasheets and studies suggesting that capacity and lifespan are noticeably reduced by being held at a low temperature. They are a chemical reaction, its behaviour is progressive, so 2C is bad, and 0C is really bad.
P.S. What were you using as your temperature reference?