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This is a TERRIBLE INSTALLATION! 😓 Parallel Batteries | Ask The Expert with NIGEL CALDER
June 21, 2025 · 3 min · 11K views
What this video covers
Jan Attenstedt and Nigel Calder analyze a house battery bank configuration consisting of seven AGM batteries wired in parallel, with some located in an engine compartment and others under a port bunk.▶ 0:18 Calder identifies two primary flaws that lead to premature battery failure.▶ 1:48 First, connecting the boat’s electrical system to only one end of the parallel string causes uneven load distribution, where the battery closest to the connection point performs significantly more work than the others.▶ 2:10 Second, the temperature differential between the engine room and the cooler bunk area causes the batteries to charge and discharge at different rates.▶ 2:31 Calder advises that all batteries in a parallel bank must reside in the same ambient temperature.▶ 2:47 To balance current flow, he recommends connecting every positive and negative terminal to a central bus bar using conductors of identical length and gauge.▶ 2:53 While saltwater submersion of the batteries creates stray current and voltage drops, it does not pose an immediate electrocution risk or cause catastrophic system failure.▶ 1:30 Proper bus bar installation ensures balanced battery life.
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