Lithium with AGM

[Zzmeyer]

I've read a lot of the threads and just get confused. I have a rather simple all AGM boat, 3 house batteries, an engine start battery and two batteries up front for the thruster and windlass. All are AGM. And 470 watts solar with Victron MPPT controllers. I want to replace the three AGM house batteries with Battleborn Lithium batteries and want to keep the AGM starter and thruster batteries. Who do I go to to help me design the system? What are the best threads that specifically address my issue? I don't want a complicated system or one that swaps out parts to be more efficient unless so compelling as to be stupid not to. In theory I'd like to drop the Lithium in and fire the system up. I know, that I have to change the charger and MPPT settings. I have a stock 80A alternator on a Yanmar that I do not want to replace as it is not a primary source of charging for me. Do I need a regulator between the alternator and the Lithium? Can I keep my existing battery combiner between the lithium and the starter battery? A thousand thanks to those who can educate this guy.

[smac999]

If you want to keep the stock alt and not destroy it.

Run the alt to the start battery. (Probably already is)

Remove the battery combiner. And add a dc to dc charger from the engine to house. I like the mastervolt mac 12/12/50. Maybe turn down to 40 or 45a. You’ll have to see how hot the alt gets and the start battery voltage it can maintain.

Leave solar on house and reprogram controller.

That will be the easiest way.