Post B4Zd0BqIWBFKSfbEYa by lykso@tiny.tilde.website
(DIR) More posts by lykso@tiny.tilde.website
(DIR) Post #B4ZczEbikjWskNKG92 by lykso@tiny.tilde.website
2024-04-06T00:54:28Z
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My sodium ion cells arrived today. 😮Gonna see if I can use them in my #MNTReform
(DIR) Post #B4ZczUqUNaqj6oMHNw by lykso@tiny.tilde.website
2024-04-06T01:16:42Z
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The neat thing about sodium ion cells, aside from being environmentally-friendly enough that they could *actually* propel us into the sort of battery-heavy future our current dependence on lithium forefends, is that they are really good at dealing with abuse. E.g., they can be completely discharged without losing capacity and they can be overcharged without bursting into flames (or even being significantly damaged, depending on *how* overcharged).
(DIR) Post #B4Zczim2avbsJ4NvOa by lykso@tiny.tilde.website
2024-04-06T01:20:40Z
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Part of me wants to just throw them into the laptop and observe what happens, and part of me wants to read the literature first and figure out a mod that allows the laptop to treat them more or less optimally. The former is a lot less time-expensive than the latter, but the notion of messing with battery cells like that makes me nervous, even knowing how much safer these are than lithium cells. 🤔
(DIR) Post #B4ZczyxyOKf4Wi5gDQ by lykso@tiny.tilde.website
2024-04-06T01:24:32Z
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Yeah, I'm just gonna throw them in the laptop and keep an eye on things. According to this, they shouldn't be damaged much, if at all, even if I let them get to the nominal LiFePo4 charge of 3.2v (relevant because those are the cells the MNT Reform is designed for): https://esst.cip.com.cn/EN/abstract/abstract1726.shtml
(DIR) Post #B4Zd0BqIWBFKSfbEYa by lykso@tiny.tilde.website
2024-04-06T01:25:22Z
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Gonna wait for this kernel build to finish first, though. Probably won't be ready for this experiment until tomorrow.
(DIR) Post #B4Zd0OI2EsZ14AfYSO by lykso@tiny.tilde.website
2024-04-06T21:07:46Z
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The experiment starts. Might be that the charge controller has no idea what to do with these cells...
(DIR) Post #B4Zd0OP7oWEdQ9zDVY by lykso@tiny.tilde.website
2024-04-06T21:11:31Z
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Well shit, it sure seems to have figured *something* out. In theory, I can let these charge to 3.6V before I see about a 2% reduction in capacity due to overcharge damage.
(DIR) Post #B4Zd0QHkotWlFsYMIS by lykso@tiny.tilde.website
2024-04-06T21:17:32Z
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Unplugged and they all immediately jumped down to 2.8V each. Charge controller is definitely baffled by these.
(DIR) Post #B4Zd0cooDp6A7s6vU8 by lykso@tiny.tilde.website
2024-04-06T21:48:03Z
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Charged fully, 3.5V each cell. Time to see how long they take to discharge.
(DIR) Post #B4Zd0enSrnDAGHUsfQ by lykso@tiny.tilde.website
2024-04-07T01:32:29Z
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Accidentally split the thread. Continued here: https://tiny.tilde.website/@lykso/112226329631159933
(DIR) Post #B4Zd16NuIPP9p7kria by lykso@tiny.tilde.website
2024-04-07T01:52:13Z
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I got exactly two hours of sitting idle and locked in sway, with a script writing out a timestamp every minute. In theory, since I overcharged them, the cells may be damaged now. I've charged them again and am discharging them again to see if there's any difference. Might be as little as 1 minute difference, if my results are in line with the paper I posted last night.
(DIR) Post #B4Zd1IhUVQCU1L0fuS by lykso@tiny.tilde.website
2024-04-07T05:53:12Z
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118 minutes to discharge that time. Seems consistent with Xu et al. Roughly 17% overcharge resulted in roughly 1.7% capacity reduction.
(DIR) Post #B4Zd1TD3QvOEc7r1Um by lykso@tiny.tilde.website
2024-04-09T04:15:12Z
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Well, I very much did not know what I was doing. At maximum charge, these give 4.1V, I've learned. The #MNTReform has a battery board that prevents under or overcharging. Seems it might have kept me from charging these things all the way up to 4.1V and possibly frying my motherboard.At any rate, they're definitely not damaged! So that's nice.