50 lines
2.2 KiB
Markdown
50 lines
2.2 KiB
Markdown
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title = "Battery discharge curves"
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weight = 1
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sort_by = "weight"
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insert_anchor_links = "right"
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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/assault-and-battery/) 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.
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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.
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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.
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Here are the graphs:
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## Genuine Sony VTC6
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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:
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You can see that it output around 2600 mAh before I stopped it at 3V, which is quite good.
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Here's a brand new genuine VTC6, again in a 3S configuration:
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This time I ran it all the way down to 2.8, and you can see it output the full 3000 mAh.
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## Fake Sony VTC6
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This is a pretty blatantly fake "Sony VTC6", brand new, in a 2S configuration:
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The performance falls off a cliff after around 3.6V, and it only outputs 1600 mAh before it dies completely.
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Trying to draw 6-7A is even more spectacular (and it gets very hot to the touch):
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Notice the huge voltage sag right as the load starts drawing.
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* * *
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<p style="font-size:80%; font-style: italic">
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Last updated on September 09, 2021. For any questions/feedback,
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email me at <a href="mailto:hi@stavros.io">hi@stavros.io</a>.
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</p>
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