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Are my BOAT BATTERIES still HEALTHY? 🔋 | Ask The Expert with NIGEL CALDER
July 5, 2025 · 2 min · 2K views
What this video covers
Jan Attenstedt and Nigel Calder explain that using an anchor windlass as a load tester is ineffective for determining the true capacity of marine house batteries.▶ 0:18 Automotive high-load testers also fail to provide accurate capacity readings for deep-cycle house banks.▶ 0:49 The only reliable method involves fully charging the battery, discharging it at a controlled rate until it reaches 10.5 volts, and measuring the total time elapsed to calculate the actual amp-hour capacity.▶ 1:00 Because this process stresses the battery, it should be performed sparingly, such as before a long offshore cruise or immediately after purchasing new batteries to verify they meet manufacturer specifications.▶ 1:28 Batteries that sit in storage for extended periods, particularly in hot climates, may suffer from sulfation and reduced capacity before they are even installed.▶ 2:19 Testing new batteries upon purchase ensures they are not defective or damaged from improper shelf storage.▶ 1:43
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