Expansion Bay Developer Program

Hm, looked at the pinout a bit, https://github.com/FrameworkComputer/ExpansionBay/tree/main/Electrical, looks like VADP_GPU is needed for providing power back to the system. Haven’t looked at much else yet, but if I’m reading it right, for a Expansion Bay battery pack, you don’t need it specially regulated, between 7.6v and 20v? Or you need it regulated to 7.6v or 20v? Likewise, 6 pins, so maximum of 90W at 20v (0.75a each)?

So if it’s a 4s battery, for example, we can simply connect (through for example a MOSFET to enable/disable) those to the 6 VADP_GPU pins, so 16.8v-12v (charged to discharged) would be just fine? Or do we need to do constant voltage 7.6v or 20v?

And looks like pins 59-61 would be ideally implemented, for the EC to talk to any battery expansion bay. Is there any documentation for the EC of what exact protocol/specs an external battery should talk?

And pin 63 to control if it should discharge, or charge from VSYS_GPU pins, right? So if high, discharge, if low, connect to VSYS_GPU to charge?