Does anyone know how to replace the battery with a much bigger battery?

Creators & Developers
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I’m designing a new chassis for my main board and was looking at replacing the default battery with a pair of 18v batteries so I can hot swap without loosing power. I plan on using the battery plug on the mainboard so I don’t take up a usb-c port.

I know I’m going to have to use a step down circuit of sorts I just don’t know what the pin out is for the default battery is and how to adapt that to the new batteries. The batteries have their own BMS system so I don’t have to worry about that.

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Battery Pinout: https://github.com/FrameworkComputer/Mainboard/blob/main/Electrical/Pinouts.md#battery-interface

You’ll probably need to dig through the EC code to figure what the data lines might be supplying: Search · battery · GitHub

If it hasn’t been documented, it looks like there’s some dedicated hardware/software for reversing laptop batteries: Hardware and Software Products - NIP Embedded Systems
and a corresponding community, eg…
https://www.laptopu.ro/community/laptop-battery-chip-reset-and-repair/hp-mu06-with-bq20z45-40-unlock-issue/

The Framework battery is a 15.4V nominal (4S) battery:

While it’s tempting to plug directly into the battery connector, to me it seems like it’d be a lot easier to just use USB-C PD - if you’re building your own case larger case, you might replace the lost USB-C with an additional de-shelled hub board even?

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Yeah I think that might be easier for sure, I think I’ll just go that route instead. Thanks for your help in my endeavour

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np, a few years ago, I built a battery powered PC for a portable VR rig using RC LiPos. Here was a writeup and some links that may still be useful for what you’re doing: Building a Battery Powered PC – random($foo)

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I was seeking a possibility to replace the battery with a bigger one. Then I found this thread. Thanks for this thread.

Here is just a note for the current Framework battery specs.

Framework | Battery
The 55Wh Battery gets you through a workday on a single charge. This pack is designed to provide up to 80% of its original capacity at 1000 cycles, and is easy to replace if you ever need to.

SKU: FRANBBAT01 Weight: 217.3g Dimensions: 239mm x 6mmx 93mm

Other FRANBBAT01, FRANBBATA01 15.4V 3678mAh original batteries - $67.47 : Laptop battery shop

  • Battery rating: 15.4V
  • Battery capacity: 3678mAh (56.64Wh)
  • Battery cells: 4-cell
  • Type: rechargeable Li-Polymer original battery
  • Battery color: black

Then I checked the battery “L140BAT-4 73Wh” used in System76 Lemur Pro with Intel 12th CPU (product code name: lemp11). It is said that it has up to 14 hours of battery life.

Clevo L140BAT-4
Capacity : 9350mAh 73Wh
Voltage : 7.7V

I am looking forward to seeing someone will replace the battery with a different one.

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With laptop batteries / cells specifically, is there such a thing as cell matching / binning?

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While there are operational ranges that need to be respected, laptops (well, all devices that use li-ion batteries) use internal BMS (battery management system) circuitry to make sure that cells are kept leveled/within safe temperature and voltage ranges so matching of cells are minimal (even if they were initially matched, they would have different wear due to position/other factors anyway so you couldn’t depend on that).

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I’m asking more from the perspective of: If I have two cells, coming off the same assembly line, same physical dimensions, could one be marked / binned as a higher capacity than the other? Thereby allowing you to sell the “packs” as higher capacity batteries without an increase in physical dimensions?

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Li-Ion batteries are generally manufactured with specific chemistry variations depending on their usage. A “high-capacity” blend of lithium substrate may store 2500-3500mAh at 3.65V, it may not be thermally efficient at high C rates whereas a “High-discharge” blend may only store 1000-2000 mAh but have a much lower internal resistance leading to much cooler operation at higher draws. These cells only pass if they are within about 8% of their rated specification. (Both the Cathode and the Anode substrates can be chemically altered to achieve different nominal voltages, different electron densities for higher/lower Ah capacities, resistances for thermal management, etc).

Unlike Silicon based manufacturing, Lithium manufacturing is not really a “lottery” whereby a lucky customer may only get 5% more capacity that may also quickly degrade back into the nominal range of capacities as the battery is conditioned.

TLDR: The only way to increase capacity without volume is a by changing the chemistry of the electrolyte and substrate at manufacturing, and deviations/lottery gains are much smaller than with silicon manufacturing. (Although a less consumer friendly case design could probably push the battery capacity to 70 or 80Wh)

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Ha!

I’m just going to download more Battery!

Best Regards,
Varg

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Now THAT is a solid plan :grin:

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