In playing with the Grin simulator, I've been modeling my pack, under "custom battery" using the total voltage and storage capacity Ah. I left the internal resistance value at whatever it defaulted to. Anyway, I tried backing into the internal resistance value of some of the existing packs from the drop down, and noticed they seem to be in the range of 0.1 ohm to 0.07 ohm, depending on the pack. My thought is that the simulator estimates the IR based on pack configuration (series and parallel groups), and applies some estimated/average values for IR at the cell level to determine/calculate the pack IR.
Since my "pack" is a combination of different cells and chemistries, in parallel and series, I will need to determine the IR for each component, based on the IR of the cells used in its parts, before combining everything into a single "pack" IR. Does this seem correct?
Main pack seems straightforward. Look at the cell spec sheet. Calculate the resistance of 8 cells in parallel, multiply by 14.
I have 14S of lipos in parallel with the main pack, so similar calculation for each battery, then summed up.
Then calculate the resistance of main pack and lipos in parallel.
Does this sound right?
I'm mainly trying to model my battery pack accurately, since I noticed, and was surprised by, how the simulator's performance results change with changes to the IR. Prior to that, I always thought in the simulator, the controller values dictate how the performance curves are calculated (battery and phase current limit), and only using voltage from the battery as an input for performance, and the pack Ah as an input for range. I can understand logically how the IR would affect performance, but puzzled by how the simulator incorporates it into the calculations.
Since my "pack" is a combination of different cells and chemistries, in parallel and series, I will need to determine the IR for each component, based on the IR of the cells used in its parts, before combining everything into a single "pack" IR. Does this seem correct?
Main pack seems straightforward. Look at the cell spec sheet. Calculate the resistance of 8 cells in parallel, multiply by 14.
I have 14S of lipos in parallel with the main pack, so similar calculation for each battery, then summed up.
Then calculate the resistance of main pack and lipos in parallel.
Does this sound right?
I'm mainly trying to model my battery pack accurately, since I noticed, and was surprised by, how the simulator's performance results change with changes to the IR. Prior to that, I always thought in the simulator, the controller values dictate how the performance curves are calculated (battery and phase current limit), and only using voltage from the battery as an input for performance, and the pack Ah as an input for range. I can understand logically how the IR would affect performance, but puzzled by how the simulator incorporates it into the calculations.
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