asked
Will this layout work to charge my lifepo4 from the alternator, while protecting the battery and alternator? See attached pic.
@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.
Thank you so much for the response. I figured it would be either the cyrix or smart dc to dc charger, but thanks to this response I'm no longer in doubt regarding the best option.
No worries! We see the Li-ct's used fairly frequently, and they're really a great solution for certain applications, but I don't like seeing them on this kind of configuration because of the lack of charge profile. Now, if you have two separate LFP banks and you're intelligently charging one and want to charge the second off the first, I'm all about the Li-ct for that, because the second will basically be receiving the same intelligent charge that the first one is, once the ct connects the two banks... but I don't like seeing Battle Borns being charged straight off an alternator. They'll take it, but it's not the best way to treat them.
I'm looking forward to being able to put Victron's B2B through its paces when it hits the shelves next year, but until then I definitely can't recommend any other brand as highly as Sterling, both for build quality as well as overall dependability.
