Few things are as annoying as stepping aboard your boat and finding that its batteries are dead. The Battery Bug from Argus Analyzers shows how much juice is left in a deep-cycle or dual-purpose battery and how much capacity has been lost; it has a replace-battery indicator and a low-battery alarm. It compensates for ambient temperature and is self-calibrating. Argus Analyzers claims that install time is less than two minutes. Battery Bugs are available for batteries of different sizes and voltages.
$39.95. Argus Analyzers, 401-398-2959, www.argusanalyzers.com