Post by lbendlin on Jan 22, 2019 5:44:57 GMT -8
It's fascinating to observe the behavior of the SunControl board , especially in the current conditions (2F for long periods of time). My goal is to be able to properly predict the charge level of the attached battery (10000mAh Li-ion), but it's really complex, especially when only considering the voltage readings of the INA3221.
When the sun is shining and the solar panel is pushing charge into the battery I see some crazy spikes in the battery voltage, and they seem to become crazier with the recent temperature drops. I tried to account for that by looking at the waste energy (stuff that is produced by the solar panel but goes neither into the battery nor to the load) but it does not seem to be a linear relationship.
I think what I'll do next is experiment with the Quad Power Management Board to temporarily disconnect the solar panel, take the battery voltage measurement, and then reconnect the solar panel (unless the battery is above 4.1V, and the charging current was down, for example)
This article helped me to understand some of the complexity
batteryuniversity.com/index.php/learn/article/charging_lithium_ion_batteries
(I am not fully convinced that the thermistor is doing its job. The battery is in the weatherbox housing, with a Zener heating, but that still gives only about 19F average temperature. Yet the INA3221 claims that the battery is charging at 800mA ...)
When the sun is shining and the solar panel is pushing charge into the battery I see some crazy spikes in the battery voltage, and they seem to become crazier with the recent temperature drops. I tried to account for that by looking at the waste energy (stuff that is produced by the solar panel but goes neither into the battery nor to the load) but it does not seem to be a linear relationship.
I think what I'll do next is experiment with the Quad Power Management Board to temporarily disconnect the solar panel, take the battery voltage measurement, and then reconnect the solar panel (unless the battery is above 4.1V, and the charging current was down, for example)
This article helped me to understand some of the complexity
batteryuniversity.com/index.php/learn/article/charging_lithium_ion_batteries
(I am not fully convinced that the thermistor is doing its job. The battery is in the weatherbox housing, with a Zener heating, but that still gives only about 19F average temperature. Yet the INA3221 claims that the battery is charging at 800mA ...)
