Post ARPQmTO17I3pbsN8u8 by AMS@infosec.exchange
(DIR) More posts by AMS@infosec.exchange
(DIR) Post #ARPN9eO3yymuZWBrG4 by adam@hax0rbana.social
2023-01-07T18:36:39Z
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I could use some #electronics help.I have there things that I want to identify. They came out of a #lithium #ion #battery pack from an electric motorcycle. The were in series with each battery cell.They read 0V and 0Ω. I want to read capacitance, but I don't have a meter that can do that. It seems like caps are the most likely thing, but I don't know how to confirm or refute that theory.Any ideas on how I might figure this out? I want to either use them or dispose of them properly.
(DIR) Post #ARPNe3IvuBiaXTHsSu by FenTiger@mastodon.social
2023-01-07T18:42:08Z
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@adam If they were in series with the batteries then they won't be capacitors; that would interrupt the circuit.Are they the same size as the battery cells? They could be dummy cells, simple short circuits so that one pack can be assembled with different cell configurations.
(DIR) Post #ARPPJtRN4Loa3ykWR6 by nlarson830@techhub.social
2023-01-07T19:00:54Z
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@adam I'm an M.E. so we still need #electronics help.SWAG that's a high amp fuse to reduce fire danger from the pack.Perhaps some sort of filter for charging but that's shaky.
(DIR) Post #ARPPRv4urbkvSY4cZk by kos@infosec.exchange
2023-01-07T19:02:22Z
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@adam looks like these without the blue casing. Even has the little ridge, bottoms look the same as well. https://www.alibaba.com/product-detail/Rechargeable-lithium-ion-batteries-3-7v_1600119233267.html
(DIR) Post #ARPQbIbsqINt0CWvo0 by phil_stevens@mastodon.nz
2023-01-07T19:15:14Z
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@adam Have you tried charging one? Outdoors, to be safe....
(DIR) Post #ARPQli1NDf1Oi2PtaK by TransitBiker@urbanists.social
2023-01-07T19:17:07Z
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@adam @TechConnectify
(DIR) Post #ARPQmTO17I3pbsN8u8 by AMS@infosec.exchange
2023-01-07T19:17:09Z
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@adam Are the fuses in battery formfactor?
(DIR) Post #ARPRikMs8avV4ackEK by aja@mathstodon.xyz
2023-01-07T19:27:43Z
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@adam A cap wouldn’t read as 0 ohms, unless defective (caps show as an open circuit in DC). Are there any manufacturers numbers on them?
(DIR) Post #ARPRyg3Xw6WIKlBGHA by Cmdrmoto@emeraldsocial.org
2023-01-07T19:30:42Z
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@adam 0 volts and 0 ohms? Your cell has shorted internally. The anode and the cathode are connected with zero resistance, as your multimeter shows. There is no road to recovery, short of extremely risky high-current pulse charging (which is about equally likely to explode the cell vs. burning out the internal short)
(DIR) Post #ARPSytC5Bs6t29q2ZE by adam@hax0rbana.social
2023-01-07T19:41:57Z
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@Cmdrmoto These are not batteries as far as I can tell, they're a component that was in the battery pack. I did have some batteries that went bad, but they all read at least a few tenths of a volt.
(DIR) Post #ARPTDvTgyrySSfFGPQ by Cmdrmoto@emeraldsocial.org
2023-01-07T19:44:40Z
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@adam alright, I didn’t read your description closely enough … inline with battery cells? But not the same cells?Maybe it’s an external cell protection module of some sort? Try this: heat one up with a hairdryer or something. Too hot for a battery pack. Measure resistance again.
(DIR) Post #ARPTGrMuiQh2aLTQ6y by yuki2501@hackers.town
2023-01-07T19:45:11Z
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@adam Aren't these just like... battery-shaped wires?I've seen them where you got a battery pack and the circuit requires less voltage than a full set of batteries, so you got 3 batteries instead of 4; you just put the dummy battery in one of the slots.
(DIR) Post #ARPTWbHgHiQhKkX1SS by adam@hax0rbana.social
2023-01-07T19:48:02Z
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@FenTiger they are the same size as the batteries. Could be, but I don't think there was a high capacity and low capacity version of this motorcycle. Plus 50% of the space seems like a lot of waste.I do plan on dismantling one if we can't figure this out. I tried peeling one that was corroded back with some pliers, but they seem pretty well put together. I think this will call for a hammer when the time comes.
(DIR) Post #ARPTqzwUJe7NbLLSYC by adam@hax0rbana.social
2023-01-07T19:51:43Z
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@nlarson830 Both pretty sound theories. Maybe a disassembly could shed more light on either of these. That's the next step if we can't figure it out without any destruction.
(DIR) Post #ARPTwidzXlG1gmQCVU by mmu_man@m.g3l.org
2023-01-07T19:52:46Z
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@Cmdrmoto @adam "in series with each battery cell."Could this be just filler things to spread heat and make the battery feel heavier?
(DIR) Post #ARPUHDyUlZreeQn1QO by aja@mathstodon.xyz
2023-01-07T19:56:26Z
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@adam At a guess, supercap to handle brief high current loads better than the Li packs. Does the resistance start going up on your highest resistance setting after a little while?
(DIR) Post #ARPUHuXMWKi6ejQSbQ by adam@hax0rbana.social
2023-01-07T19:56:37Z
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@kos same form factor for sure. I do have some batteries that look like that, but these other ones seem different.
(DIR) Post #ARPVRSj6sFtvFl2Tmi by adam@hax0rbana.social
2023-01-07T20:09:29Z
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@electronic_eel Good point about the wrong resistance. Fuses seem like a good guess.Here's what the packs look like both before and after opening them up. I had 12 of these packs.Each battery/unit is about 26 mm in diameter x 70mm long.
(DIR) Post #ARPVWIj9TkBnglMkV6 by adam@hax0rbana.social
2023-01-07T20:10:24Z
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@phil_stevensI have. The charger immediately rejects it. I have not tried to bypass that protection to charge it.
(DIR) Post #ARPVnUtzSyG2N4dSOO by adam@hax0rbana.social
2023-01-07T20:13:29Z
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@CmdrmotoYeah, inline. I posted some more pics here https://hax0rbana.social/@adam/109649734504360804Protection module seems like a strong possibility. I'll try heating one up when I get home. Thanks for the suggestion.
(DIR) Post #ARPVybGS9T1VHyR6vI by yuki2501@hackers.town
2023-01-07T19:47:18Z
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@adam If you want to test capacitance, add a simple 100 ohm resistor and plug this thing to a 5 or 12V source.Then read the voltage of the "battery" alone with a voltmeter. If it's 0V, there's no capacitance and that's the proof you need to be sure it's a dummy battery.
(DIR) Post #ARPVyc5r4M8jrOUA2i by zwol@hackers.town
2023-01-07T19:50:24Z
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@yuki2501 @adam Also, a battery-shaped wire should weigh significantly less than a real battery, right? Maybe not obvious to the hand, but a kitchen scale should be able to tell
(DIR) Post #ARPVycahDgoHP2un7A by adam@hax0rbana.social
2023-01-07T20:15:29Z
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@zwol @yuki2501 Weight, brilliant.They're both about 98 grams. I posted some more pics here https://hax0rbana.social/@adam/109649734504360804
(DIR) Post #ARPWccDk121Lq1FTe4 by FenTiger@mastodon.social
2023-01-07T19:50:11Z
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@adam If you do - post pictures, because I'm curious now. ;)
(DIR) Post #ARPWcciEBgPJMZVpAG by adam@hax0rbana.social
2023-01-07T20:22:42Z
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@FenTiger will do!
(DIR) Post #ARPWo9Y0Ro4UNvEG00 by adam@hax0rbana.social
2023-01-07T20:24:49Z
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@mmu_man @Cmdrmoto Yeah, the leading theory is that it's some kind of protection device.They want to keep the weight down as much as possiblr to extend the vehicle's range, so it's not likely to be the "make it feel heavy, and thus high quality" trick.
(DIR) Post #ARPX4KCkam2A4RzwcS by adam@hax0rbana.social
2023-01-07T20:27:42Z
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@aja That's exactly what I thought at first, but then someone suggested that it'd need to be wired in parallel for that, and that caps shouldn't have zero resistance.It's on the negative side of the battery, in case that's a clue. I posted some more pics here https://hax0rbana.social/@adam/109649734504360804
(DIR) Post #ARPYoygQWeBYt7gl4C by yuki2501@hackers.town
2023-01-07T20:47:20Z
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@adam @zwol It could be that it was a failed capacitive battery that essentially shorted but was still usable as a wire? :blobshrug:
(DIR) Post #ARPZ2uh09y1EZ6bPuq by nu@mastodon.nzoss.nz
2023-01-07T20:49:49Z
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@adam they could be some kind of protection device for the battery pack like a poly fuse or over temperature switch. I'm not sure how you would identify them if they are not marked short of disassembly.
(DIR) Post #ARPaeIfI5s0FaDC3kW by phil_stevens@mastodon.nz
2023-01-07T21:07:49Z
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@adam The dead short probably has everything to do with that.I'd most likely put on some good PPE and slice one open, curious monkey that I am....
(DIR) Post #ARPcrI9lUlltg9losC by nlarson830@techhub.social
2023-01-07T21:32:38Z
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@adam @tubetime would likely know on sight!
(DIR) Post #ARPgg5b0FrkjM0QN3w by thraeryn@hackers.town
2023-01-07T22:15:23Z
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@adam DuderAs an old-school vaper, if those aren't just unwrapped 18650s, I'll eat my hatIDEALLY, they have a circular plastic tab at the top – yours look like they do – and are wrapped in heat-shrink plastic so they don't short their shit at a stiff breeze, with only that top tap and a portion of the base exposedThat shit was laptop batteries for a dog's age
(DIR) Post #ARPhwvkxqrEzmmsUzo by zwol@hackers.town
2023-01-07T22:29:40Z
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@adam @yuki2501 Oh, *every cell* is paired with one of these? Hmm. Are you able to reconstruct a circuit diagram of the entire battery pack? I am wondering if this is maybe a shunt that can cut individual cells out of the circuit when appropriate (for instance, if one cell reaches full charge before the rest of the pack)
(DIR) Post #ARPx7YzyIuNHhXQSau by adam@hax0rbana.social
2023-01-08T01:19:32Z
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OK, I figured it out. They ARE batteries! It just so happened that every one I tested was incredibly bad, but I found at least one that was still good. Insufficient testing. My bad. Glad I didn't try to open one though.Thank you to all who played along in my mystery challenge.cc: @FenTiger @nlarson830 @tubetime @kos @electronic_eel @phil_stevens @TransitBiker @AMS @Cmdrmoto @mmu_man @yuki2501 @zwol @aja @nu @thraeryn @e_er1n and anyone else who I missed!
(DIR) Post #ARPxGB06tdmLsbb6wq by Cmdrmoto@emeraldsocial.org
2023-01-08T01:21:12Z
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@adam @FenTiger @nlarson830 @tubetime @kos @electronic_eel @phil_stevens @TransitBiker @AMS @mmu_man @yuki2501 @zwol @aja @nu @thraeryn @e_er1n yow! Good thing you didn’t go for the aggressive thermal testing after all
(DIR) Post #ARQ1tNkBqoeUVq6Krg by falcon@mastodon.falconk.rocks
2023-01-08T02:13:06Z
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@adam if they were capacitors, you would most likely see the resistance reading from your ohmmeter rise gradually. Whatever this is, it's most likely a failed component. They look like cells to me; capacitors would not be in series and would be unusual for this application.
(DIR) Post #ARQEXYQkjkfAgnvp4q by aja@mathstodon.xyz
2023-01-08T04:34:46Z
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@adam Yeah, they should be in parallel for that use. It is possible for a cap, when fully discharged, to show a very low resistance at first (during the charging transient) before settling into the steady state DC response (effectively an open circuit).
(DIR) Post #ARQIfxzTzLAA61RWlc by swrdghcnqstdr@mstdn.social
2023-01-08T05:21:11Z
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@adam They’re definitely unwrapped 18650s, almost every large lithium ion battery pack nowadays is just a bunch of 18650s (including Tesla batteries iirc), but even though you said it’s every other cell, i’d be willing to bet these are dummy cells. Just a 0Ω resistor in the shape of a cell to maintain the structure of the battery pack without adding any power.