Batteries in series don't drain equally.

[rc car guy 521]

Hi. I've been running my lipos in a series. 2, 2cell, 5000mah, 50c, batteries. When I start the voltage on both bateries are the same but after some use, voltage in one battery is much lower than the other one. The batteries are pretty much the same age. Why do they drain at different rates.

[fhhuber]

Different internal resistance is the short answer.

The numbers can all say the same thing on the batteries, but even with the same lot number there are variations in LiPos.

[rc car guy 521]

thanks. that helped a lot!