New Librem 14 will not power on

I’m having essentially the same issue as described here (sorry for creating a new forum post, didn’t see this one when I was looking). My L14 is working fine with the 4 cell battery, but does not work with the 3 cell battery (no charging, not booting). I was on i think 1.09 of the EC firmware, not updated to 1.11, no difference.