Lithium and Alternator: How to Charge Engine and Bow Thruster Batteries (Balmar, Wakespeed, and Vtronix)
March 18, 2026 · 21 min · 4K views
What this video covers
A Beneteau Oceanis 50 owner upgrades the charging system to support a LiFePO4 lithium house bank by replacing the stock alternator with a 120-amp Balmar unit controlled by a Wakespeed regulator.8:11 The Wakespeed regulator integrates with a Victron Cerbo GX, allowing for programmable current limiting and real-time monitoring of alternator and battery temperatures.9:41 To prevent alternator damage during a Battery Management System (BMS) disconnect, an external Sterling Alternator Protector is installed to absorb high-voltage spikes.11:41 For the engine start and bow thruster batteries, a Victron DC-DC charger draws power from the lithium house bank, while a Victron Cyrix-ct intelligent combiner relay manages the charging priority between the thruster and engine batteries.15:16 A manual battery switch is installed on the alternator output cable to ensure safety during maintenance, as the connection to the house bank remains permanently active.20:12 Proper cable sizing and voltage drop calculations are essential for this configuration.
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