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content/maker-things/_index.md

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 Click on a link in the list below to go to that page:
 
+1. [Battery discharge curves](../../maker-things/battery-discharge-curves)
 1. [Electronics tips](../../maker-things/electronics-tips)
 1. [GRBL_ESP32 tips](../../maker-things/grbl-esp32-tips)
 1. [How to properly level your 3D printer](../../maker-things/how-to-properly-level-your-3d-printer)

content/maker-things/battery-discharge-curves.md

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+title = "Battery discharge curves"
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+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.
+
+* * *
+
+<p style="font-size:80%; font-style: italic">
+Last updated on September 08, 2021. For any questions/feedback,
+email me at <a href="mailto:hi@stavros.io">hi@stavros.io</a>.
+</p>

content/maker-things/electronics-tips.md

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 title = "Electronics tips"
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+weight = 2
 sort_by = "weight"
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content/maker-things/grbl-esp32-tips.md

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 title = "GRBL_ESP32 tips"
-weight = 2
+weight = 3
 sort_by = "weight"
 insert_anchor_links = "right"
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content/maker-things/how-to-properly-level-your-3d-printer.md

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 title = "How to properly level your 3D printer"
-weight = 3
+weight = 4
 sort_by = "weight"
 insert_anchor_links = "right"
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