The scenario
A camper van uses a starter battery and a house battery, with an alternator charging the starter battery and a solar panel charging the house battery. An automatic voltage-sensitive relay connects the batteries when the engine runs and isolates them when stopped.
What is in this drawing
Read the decisions behind it.
01
Voltage-sensitive relay (VSR) energizes from the alternator output to connect the house battery only while charging.
02
A Schottky blocking diode prevents backfeed from the house battery to the solar panel at night.
03
Separate fuses protect alternator, solar, and house load circuits.
Use as a reference when designing or troubleshooting dual-battery systems in camper vans, boats, or off-grid vehicles that combine alternator and solar charging.
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