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Solar Charging Dual Bank 12v and 48v Lithium Batteries - Cape Dory 36 Refit Part 5
November 22, 2023 · 10 min · 4K views
What this video covers
A Cape Dory 36 refit carries both a 200 Ah 12-volt lithium house bank and a 175 Ah 48-volt lithium bank powering a 6 kW electric outboard that replaced the original diesel.Watch Two 200-watt 12-volt solar panels on an arch charge both banks using a transfer-switch arrangement: each panel feeds its own three-position transfer switch, letting the operator direct output to either bank independently.2:37 Wiring four panels in series to reach 48 volts was rejected because partial shading from the mast or sails across even one panel collapses output across all series-connected panels.0:53 Instead, each panel's 48-volt path runs through its own 300-watt boost MPPT charge controller — two unbranded $31 units rather than one 600-watt controller, for cost and redundancy.5:14 The 12-volt path combines both panels through a single 30-amp Victron MPPT.4:38 A 48-to-12-volt converter lets the motor bank top up the house bank when propulsion demand is low.3:16 Shore power uses separate 120-volt chargers, one per bank.0:22 The boost controllers offer user-programmable output voltage and draw no standby power; Atom walks through the single-button programming sequence.5:42 A wiring schematic is available.7:32 Two smaller boost controllers cost less and add redundancy compared with one higher-wattage unit when charging a 48-volt bank from shaded 12-volt panels.5:30
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