I needed this battery and never knew it existed. I'm glad I saw your video, and not just because I want keyless start on my bike. I'm going to use the battery to power a PocketFinder vehicle tracker when the bike is off. I think now you're charging the it off the DC:DC converter. Did you consider charging off the AC port using the AC adapter instead and if so what were the drawbacks? Unfortunately, I'm not sure I ride enough to keep the Talentcell fully charged.
I'm also glad I found this battery! It's honestly the perfect thing for those of us who want an always on 12 volt source!
To be honest, I never even thought about using the AC port to charge this battery bank! That's a great idea! The only drawback I can think of for your application is: it's going to be really difficult to tap into the bike's AC port. Those wires are heavy duty and well protected. Not to mention they are hidden behind the frame of the bike and hard to get to. Zero also recently changed their charging recommendations. It's no longer recommended to keep the bike plugged in all of the time when not in use.
I don't think I would use the AC port only to charge the battery for my keyless system though because when the bike is ON it's using more power than usual because it's powering two relays. And if I'm charging my phone, it's drawing even more power for that. So I personally think charging the battery from the bike's 12 volt DC:DC is the way to go for my application. Then you never have to worry about the additional power consumption when the bike is on.
I guess the ideal solution would be to have it charge from the AC port when the bike is off and plugged in, and have it also charge from the bike's 12 volt DC when the bike is on.