Why does the current in my battery simulation appear as negative?

I have a simulation set up after following the steps in the battery builder guide, with the parameters adjusted to my needs. Why does the current appear as negative in the simulation?

Answer 1

[TED MOSBY]

Hi Zachary,

Current appears as negative because of the signing convention, so there is nothing wrong in your model.

For every two‑terminal electrical block in Simscape, current is defined as positive when it flows into the block’s first (+) conserving port and out of the second (–) port. In the BatteryEquivalentCircuit and all the BatteryBuilder cells, that first port is the cell’s positive terminal. When the pack is charging current flows into that + port, so the reported I is positive; when the pack is discharging current leaves the + port, so I is negative.

So the negative sign is expected whenever the battery is delivering power. If you prefer the oppsite sign, you may swap the sensor orientation (flip the Current Sensor or the measurement port)

Hope this helps!

[Zachary]

How do I swap the sensor orientation? I'm using a terminator that is connected to iCell and vCell of the battery pack.

[TED MOSBY]

Could you share your model? It will be helpful for me to answer your query, thanks!

[Zachary]

Here you go, thank you for the assistance!