+++ title = "Battery discharge curves" weight = 1 sort_by = "weight" insert_anchor_links = "right" +++ I wanted to buy some Sony VTC6 batteries, and I was wary of fakes, so I wrote a [battery discharge calculator](https://gitlab.com/stavros/battery-discharge-calculator/) with an associated hardware component (just a simple current and voltage sensor). I then took some measurements of my known-good batteries, and the new ones I bought. The methodology was the following: I connected the battery to the sensor, and the sensor to a configurable load. I set the load to draw a certain amount of amps until it reached a cutoff voltage, and then to stop. I then plotted mAh drawn versus voltage, as well as amps drawn. The batteries I connected were in various states of use, and various configurations (for various reasons, I couldn't test single cells). The configuration, state of the battery and provenance are mentioned below. Here are the graphs: ## Genuine Sony VTC6 This is a genuine (as far as I can tell) Sony VTC6, fairly used in high amp draw situations (I use it in my plane), in a 3S configuration: ![curve_old-3s_2021-09-08_02-53-53.png](../../resources/58a35a63ebd14513b13a8e50c6938289.png) You can see that it output around 2600 mAh before I stopped it at 3V, which is quite good. ## Fake Sony VTC6 This is a pretty blatantly fake "Sony VTC6", brand new, in a 2S configuration: ![curve_new-vtc6_2021-09-08_18-54-58.png](../../resources/1be705ff4fe44682b6491cf8631effe7.png) The performance falls off a cliff after around 3.6V, and it only outputs 1600 mAh before it dies completely. * * *

Last updated on September 08, 2021. For any questions/feedback, email me at hi@stavros.io.