question

@Luke78, the weakness that I see here is that your alternator isn't putting out the intelligent 3- or 4-stage charging profile that your lithium wants to see. Will it work with the Li-ct? Yes, it will... but the Li-ct is just connecting your two batteries, it's not actually regulating the charge. So it'll work, but it's not treating your Battle Born as well as you could, which will lead to a shorter life span overall. Now, realistically that's on the order of maybe a hundred fewer cycles over its life, which on one hand is somewhat negligible, but on the other hand we stock Battle Borns so I know how much they cost... if you're going to invest that much in a battery, I'd pretty strongly recommend investing another few hundred dollars in an intelligent battery to battery charger or an alt-to-batt device that's going to treat that lithium well.

Personally I'd recommend, rather than the Li-ct, either a Sterling B2B charger like the BB1260 or a Sterling Alt to Batt charger like the AB12210 (we're a Victron distributor too, so no disrespect to Victron intended; for this purpose, though, Sterling has a better range of appropriate products). Both the B2B and the Alt2B devices have customizable LiFePO4 profiles that will treat your BB a lot better than the Li-ct.

You could also wait just another few months for Victron's smart B2B charger to hit the market... if you're trying to stay all-Victron, that'd probably be your best bet.

Bottom line, your Li-ct will work, it's just not the best solution to keep your BB in top shape.