Can You Mix Lithium and AGM Batteries on a Boat? DC-to-DC Charging Explained - PYS Tech Talk
20 October 2026 · 3 min · 4K views
What this video covers
Mixing lithium house banks with AGM batteries for bow thrusters or windlasses is feasible using DC-to-DC charging converters.2:58 Previously, disparate battery chemistries caused charging conflicts because standard chargers could not accommodate multiple voltage profiles simultaneously.1:29 Modern DC-to-DC converters, such as those manufactured by Victron, isolate the battery banks and allow for independent, customized charging profiles for each chemistry.2:12 This setup enables a boat to maintain a lithium house bank while utilizing AGM batteries for high-draw equipment like windlasses, avoiding the unnecessary expense of lithium for auxiliary loads.0:52 Jeff Cote confirms this configuration is standard practice on his own vessel, where a DC-to-DC converter manages the charge from a lithium bank to a flooded lead-acid engine battery.2:23 These converters replace traditional battery combiners or parallel switches, ensuring each battery type receives the specific voltage required for optimal health and longevity.2:01
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