I do not know if the Victron "carbon" batteries use the same technology as the Firefly. I assume if you asked them they would answer if they licensed the Caterpillar patent. Victron's claims are quite a bit more modest.
Firefly's supply problem is more than supply chain I am afraid. It looks like all of the US distributers in the marine
market have dropped them. I strongly suspect that the distributers became fed up with quality control issues out of the factory in India
We have a 24V bank of 8 G31 Firefly batteries, and it is everything the advertising copy says it should be, BUT... it took several iterations and warrantee claims before we were able to put together 8 batteries that all worked. I strongly suspect that between the technical service
and replacement product nobody made any money
on our installation
It's a shame, when they work
they are a great cost effective alternative to Li, but the "infant mortality" of the product we experienced was a real problem. I do not know if the issues are just poor QC or it the problem is inherent to the technology. I would not expect problems from a similar product from Victron.