After a lot of testing and tweaking, I’m finally happy with how my Lithium iron phosphate or LiFePO4 batteries are charging using my narrowboats alternator. Initially, the charge was too harsh so I used a Victron BMS 12/200 to regulate the current and give me the option to disable the charge when I want to.

Victron BMS 12/200
https://www.victronenergy.com/upload/documents/Manual-BMS-12-200-EN-NL-FR-ES-DE.pdf

https://www.onboardenergydirect.co.uk/cgi-bin/sh000001.pl?WD=200%2012%20bms&PN=victron-bms-12-200%2ehtml#SID=108

Victron Alternator Control Cable
https://www.victronenergy.com/upload/documents/VE.Bus-BMS-to-BMS-12-1200-alternator-control-cable-EN.pdf

https://www.onboardenergydirect.co.uk/cgi-bin/sh000001.pl?WD=alternator&PN=Victron-Lithium-Battery-Alternator-Control-Cable%2ehtml#SID=108

Marine Grade Battery Box
https://www.midlandchandlers.co.uk/store/product/30640.aspx

Blue Sea 300A Switches
https://www.onboardenergydirect.co.uk/shop/8-29006-battery-master-switch.html#SID=45

Victron BMV 712 Battery Monitor

https://www.victronenergy.com/panel-systems-remote-monitoring/bmv-712-smart

https://www.onboardenergydirect.co.uk/cgi-bin/sh000001.pl?WD=712&PN=Victron-BMV-712-Smart-Battery-Monitor-with-Bluetooth%2ehtml#SID=21

Blue Sea MaxiBus Insulating Cover 2719
https://www.bluesea.com/products/2719/MaxiBus_Insulating_Cover_for_PN_2127_and_2128