I have the same old idea: put framework motherboard into ThinkPad T60 chassis.
I have googled a lot, read and collect all possible information and looks like everything was discovered and done before, except charging/powering from non OEM battery.
In all project I have see, stock framework battery is used. Except one (it is not framework, but still indicates it is possible).
There is no clear answer, so I try to find missing bits of information:
Is there any documentation on charging port (I have seen pins in github repo) about charging controller? What batteries could be supported and what Volt range are ok?
For sure if there is some existing case of using non OEM battery with framework, please, share the link, I could miss it.
Ah, I was just about to link to some of the threads asking about using other batteries. Several people have made threads or asked in existing threads, but once they find out what’s involved, that’s usually the end. Couple of them here & here. I don’t recall anyone following through, or even looking into the EC’s code to just see how easily it can be changed for an alternate batteries’ BMS. This being Framework, the EC code is open source and on their github.
Do you know what BMS chip the ThinkPad T60 battery uses? You’ll need to read the datasheet on it, if you haven’t already. The T60 is from 18 years ago.
I do not know what BMS chip is used in T60 battery, but I have a conversation with person who has crafted the swap I mentioned before. He placed in open source battery controller that works with T61 (it is the same battery as in t60). That info could help to “understand” what T60/T61 batteries “like”. The author of that swap point me that ThinkPad T61 battery is “3 series 4.2 volt cells so when fully charged, the pack will measure about 12.6 VDC” and his custom controller could be replaced with that one (could not post the link because of limit, will do in separate comment).
So that is information I was able to collect over batteries T60/T61.
My idea if there is a chance to compare framework charging board logic to those controllers, could give an idea if that is doable out of the box by just repin connector or is that will require some middle board and would be not really easy. Could you point me to EC codes in gitrepo?
I’m afraid detailed mainboard schematics are only available to repair shops, if they apply for them. They do need to sign an NDA, because I believe the boards are developed with partner(s) who may not be as enlightened as Framework themselves about releasing full schematics of their work. But schematics aren’t needed, the battery pinout & EC code is all one really needs.
I wouldn’t expect the EC to just accept any battery you connect without tweaking the EC code. Even if had the ability to talk to and fully understand the particular BMS, large li-ions not managed correctly are too dangerous to just accept automatically. Li-ions can & have killed and burn down homes. Especially if the cells aren’t from reputable manufacturers, or they aren’t managed correctly.