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Joined 1 year ago
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Cake day: October 9th, 2023

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  • A bit of an update here: I decided to do it. Basically, 1st you need to desolder the flex cable, starting with 2 positive wires and not shorting them to other stuff (I haven’t tried doing it myself, but it doesn’t seem like a good idea)

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    Then solder everything but positive, isolate, solder positives, isolate. I used hot glue since I’m in the middle of nowhere and too impatient to wait for some more appropriate stuff to be delivered.

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    Then install the contraption into the case which doesn’t fully close now, but it’s unnoticeable when plugged in into the laptop.

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  • I didn’t build it, although I’ve been entertaining the idea for quite a while. I just happened to have 2 dead batteries, one 72wh with a locked controller (2 parallel cells simply fell off due to bad spot welding) that I later bricked while trying to unlock, and a 22wh with one of the packs dead. So, after fixing the welding (tbh I’ve just soldered those cells since I didn’t have a spot welder myself at the time) I just swapped out the working controller with the locked one. T480 doesn’t seem to mind, so whatever. Although I eventually decided to set the charge threshold at ~90% since it seemed to me the BMS overcharges the batteries

    As for building, there’s this beauty (also there’s a hackaday article about it; includes a link to the blog post outlining how it was done) for t420 which seems to include a PoC-ish smbus implementation for an attiny, as we’ll as a prototype based on bq3060. Verification may be a problem, tho, if the board runs on EC firmware from lenovo (also, I’ve been looking at coreboot docs for x230 today, and yap, they sometimes do keep blobs with EC firmware, although there were tutorials on patching it to remove the verification). Also, if you happen to have a battery based on bq8030 ic, this blogpost has a disassembler for its firmware, which makes it possible to more or less see how the battery side of verification is done and implement it some other way. Dumping the firmware is also quite simple using theese scripts (tested on the second battery mentioned in the post)



  • I guess so, but you should check which controller is used on your bms. This guide targets bq8030, as mentioned in the readme

    Edit: also, my bad: it looks like the guide doesn’t show how to change the battery capacity, so recalibration is also necessary (alternatively, you can look for the values reported by /sys/class/power_supply/BAT*/energy_full{,design} in the dumped firmware and change them. However, the script is useful if your bms locked itself (in this case replacing/shorting the fuse might also be necessary, as some bms-es try to blow it when locking)



  • I cheated a bit: I had 2 dead batteries, one 72wh with a locked bms and a 22wh with one of the batteries dead, so I just soldered the batteries from the 1st one to the bms from the 2nd one leaving the factory welding in place. *Also, before disconnecting the original batteries I soldered another fully charged battery in parallel in order not to lock the bms, which may’ve been unnecessary given it didn’t lock with one of the original packs showing 0v, but better safe than sorry.

    As for soldering the cells, it’s generally not advised, but is kinda ok if you’re fast enough and have good flux. The trick is not to overheat the batteries, and that’s it.

    Also, I wrote a small calibration script (which is a fancy word for charging and discharging the battery a few times to let the bms know the cells have changed; mb helpful if you decide to give it a try (also there’s tlp recalibrate, but I wanted to try amber out, so here we go :D)




  • fl42v@lemmy.mltoUnixporn@lemmy.mlBedrock rice
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    3 months ago

    A so-called “meta distribution”, allows you to mix and match packages from some other distros. Kinda like distrobox, but older (AFAIK) and low level-er.

    That said, I didn’t find it exactly useful a few years ago, since pretty much everything i needed was in the aur or the official repos (should be better if the base was smth like Ubuntu)