Introducing MNT Reform Next https://mntre.com/media/reform_md/2024-09-09-introducing-mnt-reform-next.html
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@mntmn why are all the laptops so thin these days? Ethernet only via dongle is quite the indicator against for me… though without an IBM Trackpoint option I’ll probably abstain anyway. (But good luck.)
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@mirabilos I do have a couple of ix to rj45 cable at home that would make the "dongle" redondant.
The IBM trackpoint was patent encumbered until recently afaik so good luck finding the component to make an open source keyboard with one.
The battery powering this laptop are cylinder with a diameter of 18mm. It's probably at least 3cm thick with the screen. I would hardly call that thin. -
@mntmn the page mentions some hardware close to when it mentions different chemistries, theses being LiFePO4 and Li-ion. Any idea if fully supporting a sodium-ion battery could be done in firmware?
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@gkrnours @mirabilos 26mm
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@mntmn If both battery packs have their own charge control subsystems, is it possible to have the system draw power preferentially from one of them, for purposes such as hotswap management and battery wear level staggering?
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@gkrnours I haven't looked at the chip's datasheet yet. It's billed as 'multi-chemistry'; there's a hope that the chip might not have hardcoded algorithms, but parameter sets, so when a new battery chemistry gets invented, the new firmware will just have to load the new battery charging parameters into the charge controller.
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Which is significantly thinner than the legendarily small and cute Toshiba Libretto 70ct and 100ct at 35mm.
@gkrnours @mirabilos -
Riley S. Faelanreplied to Riley S. Faelan last edited by
I just realised that it's a modular laptop. The design team can probably arrange the charge controller to reside in a module that can be individually replaced later, in case it should turn out that the original design will not be retrofittable for future battery chemistries.
I'll dig up the previous model's schematics and try to find out the original MNT Reform handled this.
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Riley S. Faelanreplied to Riley S. Faelan last edited by
@gkrnours Looks like it's not a separate module in the MNT Reform; it appears on the motherboard's schematic. They used LTC4020, which looks pretty fancy, and at first glance of the datasheet, can probably be reconfigured for NaIon batteries, once they're available. (The datasheet explicitly mentions that it supports LiIon and, of all the things, lead acid batteries. LiFePO4 is not explicitly listed as supported, but if it can be reconfigured from LiIon to LiFePO4, it can probably handle NaIon as well.)
But ISTR that the MNT Reform Next will be using a TI's charge controller, so it would probably be reconfigured in a completely different way.
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Riley S. Faelanreplied to Riley S. Faelan last edited by
Page 2, https://mntre.com/documentation/reform-handbook/_static/schem/reform2-motherboard25.pdf. LTC4020's datasheet is at https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4020.pdf. As you can see, it's a fancy chip of a power-wrangler.
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Riley S. Faelanreplied to Riley S. Faelan last edited by
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@gkrnours The electric characteristics of NaIon will probably look a lot like LiIon; only the voltages might be different. In the worst case scenario, the charge controller is 'programmed' by using resistor voltage dividers, requiring these resistors to be replaced in order to retrofit the old system for new batteries. But charge controllers can be more flexible than that.
The other potential bottleneck is, if the new voltages are significantly higher, the power path to them, or possibly the cell balancing mechanism, might not be able to safely handle the higher voltage. But that's unlikely to be a problem; the low-hanging fruit heuristics suggests that lithium batteries' voltages are probably among the highest readily available, and new battery chemistries are going to have lower rather than higher ones. (The voltages are remarkably stable, and can be calculated from shape and measurable properties of the electron clouds of the various metals. I have forgotten how this works, but the people who invented lithium batteries knew, and lithium being able to put out a relatively high voltage probably figured fairly high among their choice-making.
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@gkrnours Voltage won't be the issue. Power, potentially, might — for the same wattage, you need proportionally higher amperage, and higher amperage brings higher losses in the wiring, to be compensated with thicker wires, or wider traces on the PCB, lest the system run hot.
But, well, these laptops are calculated for LiFePO4 battery chemistry, with a nominal voltage of 3.2V, so the difference is likely only marginal.