My DIY bms attempts to regularly determine the internal resistance of all cells. I expected it to remain the same until the cells got older but instead I noticed that it was constantly fluctuating - it increased and decreased based on SOC and the duration of the current.
After some research I found a paper that I thought might be interesting to some here.
Take away points are, I believe:
Internal resistance varies with SOC
Internal resistance is different at different current points
Internal resistance does not stabilize until at least one minute has passed at a given current
In short, there is no single value for internal resistance for a lifepo4 cell...
This might actually matter when charging or discharging your cells with higher currents and trying to control voltages.
After some research I found a paper that I thought might be interesting to some here.
Take away points are, I believe:
Internal resistance varies with SOC
Internal resistance is different at different current points
Internal resistance does not stabilize until at least one minute has passed at a given current
In short, there is no single value for internal resistance for a lifepo4 cell...
This might actually matter when charging or discharging your cells with higher currents and trying to control voltages.
