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121 lines
6.7 KiB
Plaintext
121 lines
6.7 KiB
Plaintext
Episode: 3816
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Title: HPR3816: Post Apocalyptic 4s5 Battery Pack
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Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3816/hpr3816.mp3
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Transcribed: 2025-10-25 05:53:16
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---
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This is Hacker Public Radio Episode 3816 from Monday the 20th of March 2023.
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Today's show is entitled Post Apocalyptic Forest 5 Battery Pack.
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It is part of the series Hobby Electronics.
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It is the 10th show of Mechatraniac, and is about 8 minutes long.
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It carries an explicit flag.
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The summary is, tough battery design worthy of the Post Apocalyptic Robotics Database.
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Hey what's up is Mechatraniac, Mechatronics, maniac here again on the spyware audacity.
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Today I'm going to put something into the public domain that's not at all abominable.
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It is pretty cool.
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Well the MP3 player last time was pretty cool too, but it's also abominable.
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So hopefully you can access the images.
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They're going to help, maybe not mandatory, but it will help to look at the images.
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So pick 0 is the 4s5 battery schematic.
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You might have seen last time I did a video about the mobile computer battle stations.
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And you may have recall that that point that I had a 4s4 system means 4 series for parallel.
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So this time I'm going for s5, which is one extra parallel.
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But I had this all sealed up, but I noticed that my voltage was dropping off.
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I was charging the computer.
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So I used to go from this BMS module to the boost converter that turns the 16.8
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and below from the battery to 19 volts to charge my laptop.
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And the boost converter, it's just a board with some stuff on it and has a little pot
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that you can adjust for the output voltage and that's it.
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So yeah, you definitely need a volt meter if you're going to do boost converter stuff.
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But anyway, the zen of post-apocalyptic robotics has smiled upon me.
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But anyway, I was, like I said, I was noticing that the voltage was dropping.
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And then on the board, you can measure between 0 and between 0 and 4.2 volts,
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between 4.2 volts and 8.4 volts and all those test points.
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So I checked and from 4.2 volts to 8.4 volts, it was much lower than the other ones.
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So I took those apart and so I get to show you the inside,
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because I didn't have that camera when I was building this thing originally.
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So this is the really zen of post-apocalyptic robotics here,
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because I had the 4s4 that I built the last time and I had problems with it disconnecting at
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points. I had to like open it up and resolder it all the time.
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So I needed a solution for that. It's just wrapped in cardboard.
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So I needed something like stable, like metal or something as base plates,
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so that it would be rigid and not have flex to it and not wreck the solder points.
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And what I found is that a DVD drive case like for a computer or whatever works perfectly.
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It's like the perfect size when you set up.
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If you look at pick one, you can see the dimensions of it.
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And it just so happens that a DVD drive case fits perfectly over this,
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like the two halves of it. There's one half of the DVD case that has more
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about like a lip on it and that's actually nice.
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On picture six, you can somewhat see the lip coming down.
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So pick one I cut through the tape and cardboard and you can see on pick two,
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you can see the ribbon strip of metal that's holding the batteries together.
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Pick three is another detail of the solder points between the two cells.
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And pick four is actually, so I took that ribbon off.
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This is bank two between the 4.2 and 8.4 bolt points.
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And one or more of these cells was bad.
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Actually on pick four, it shows the new cells in there.
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Pick two, you can see they're different colors.
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So when I took that strip off the one side, I could measure each voltage without
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having to remove the strip on the negative terminals.
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So I found two that were low and we're actually depleting while I was measuring them.
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So okay, so I've got some new ones in there.
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Hopefully they'll be better.
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Snug them in there, pick five and pick six.
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I've got the DVD case on there, pick seven,
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taped it right up real nice.
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And pick eight shows the BMS board.
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So I use a solar power cell to our solar power panel to charge this.
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And I built some more panels as well, but it works really well from the solar panel.
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And pick nine is an outdoors picture of it in action.
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And so all this stuff is post-apocalyptic, sourced from dead electronics, except for the BMS.
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But at some point should be able to do that as well.
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I recommend watt hour YouTube channel.
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He does a analysis on one of the 12 volts units, which is only three cells.
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This one has four, which is better for my purposes, because it's perfect for
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charging with the 18 or 20 volts that I get from my solar panel.
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I've also added a mall X connector.
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And that actually plugs into my battle station where I have the boost connector set up,
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which is actually the case for my laptop that it originally can.
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It's getting a bit beat up now.
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It's only cardboard, but I covered it in tape.
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I won't go into that today.
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We'll just keep it on the BMS stuff.
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So last time, if you want to zoom in on pick eight, you might be and should be able to see.
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So the last time I did a major brain shark, because if you can see the input and output,
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if you look at my schematic, the input and output are the same terminals plus and minus,
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which I found to be bizarre, because on the on the 1s chargers that I one of which I used on
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the previous podcast about the abominable post-pocalyptic MP3 player, it has separate input and output.
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So this was confusing for me.
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Well, it wasn't confusing.
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I just had a brain shark, the totally the wrong thing, and went from the battery zero volts,
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and the battery 16 volts directly from the battery for my output.
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And I didn't realize that the input and the output are the same.
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So you just plug that in.
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And before I had to worry, because I was going directly from the battery,
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there was nothing stopping it from over discharge,
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I had to worry about it draining the shit out of my battery,
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even though the boost converter stops around 8.4 volts.
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That's already too low.
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You want it to be around 12 volts.
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Anything goes below 2.5 volts on your cells.
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It's bad for the cells.
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So that's really good to know.
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Now, once it goes below 2.5 volts on any cell bank,
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it will just automatically turn it off.
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So that makes it a lot better.
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All right, I think that's about it for now.
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Hopefully it's not too confusing.
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The schematic should make sense.
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All right, this is the McTry FHPR out.
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You have been listening to Hacker Public Radio
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at HackerPublicRadio.org.
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Today's show was contributed by a HPR listener like yourself.
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If you ever thought of recording podcasts,
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you click on our contribute link to find out how easy it really is.
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Hosting for HPR has been kindly provided by
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an honesthost.com, the internet archive, and our sync.net.
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On the Sadois status, today's show is released
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under Creative Commons,
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Attribution 4.0 International License.
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