Major Battery Voltage Drop during Throttle-Up

🧪 Flight Testing & Log Analysis
1

Hey guys,

During my last flight test I tried switching from a 4s to a 6s battery. My equipment setup is a holybro PM07 distribution board, Pixhawk 4, Kotleta 20 ESC’s and BrotherHobby Avenger V2 2507-1500KV motors. When switching batteries I made sure to change the battery type from 4 to 6 cells and recalibrated ESC’s. When throttling up the voltage dropped in half in the current spiked to the limit of my PDB to compensate.

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Does anyone know why this might happen? This battery is a turnigy 6s 3000mAh and was left at storage voltage until about 1 day before flying when it was charged. It has never been used before then.

https://review.px4.io/plot_app?log=7be2c64f-b2f2-462f-a890-837397eabe65

2

Hi,

That might be caused by internal resistance of the battery.
http://www.learningaboutelectronics.com/Articles/Battery-internal-resistance

If the internal resistance of the battery is around 100mΩ, which is common value, that big voltage drop will occur.
LiPo chargers are often able to measure the resistance, so you might want to try.