BoatHowTo · video

What this video covers

Battery isolators do not protect alternators from overheating when charging lithium-ion battery banks.▶ 0:23 Jan Attenstedt and Nigel Calder explain that standard diode-based isolators are passive components that lack current-limiting capabilities.▶ 0:33 If a lithium-ion bank demands more current than the isolator’s rated capacity, the device risks failure.▶ 0:41 Because lithium-ion batteries can absorb high current levels, the alternator may run at maximum output for extended periods, leading to potential damage.▶ 0:41 To manage this, Calder recommends installing a battery-to-battery (B2B) charger between the AGM and lithium-ion banks to provide current limiting and a proper charging algorithm.▶ 1:47 Additionally, diode-based isolators often cause voltage drops that prevent optimal charging; switching to FET-based technology eliminates this drop.▶ 2:00 Proper system design requires matching the isolator rating to the maximum alternator output and using dedicated charging hardware for lithium-ion chemistry.

More from BoatHowTo

SODIUM ION Batteries - the Future of Boating or Marketing Hype?| Ask The Expert with NIGEL CALDERJul 2026Are Household POWERSTATIONS a viable Solution ON BOATS?? | Ask The Expert with NIGEL CALDERJul 2026ONE SWITCH for TWO PUMPS?? (Pontoon Boat Setup) | Ask The Expert with NIGEL CALDERJul 2026OIL LEAKS at the Crankshaft... | Ask The Expert with NIGEL CALDERJul 2026

From BoatHowTo — see the channel’s boat, crew, and every analyzed video.

The Sailing Directory Newsletter

One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.