Ask PYS: Power

Lyall, on Aug 13, 2010 asked:

The house bank (four golf-cart batteries) on my 36 foot Bavaria is drained after a day of use at anchor. What is your recommendation for solving my power needs?

Hi Lyall,

My approach for marine power systems is systematic. First, gauge the batteries with a digital battery monitor, so you can know your daily consumption, i.e., Amp hours (Ah). A battery monitor is like your fuel gauge - it's absolutely essential. A battery monitor will inform you of exactly how many amps you are using at a given time and, more importantly, how many you've used over a period of time. Second, make sure you have a dedicated engine and house battery bank. Battery bank separation is key for reliability and safety. Third, by installing a special battery combiner (e.g., BlueSea's ACR or "Automatic Charging Relay") you'll be able to automatically charge both battery banks without using the battery selector switch. Fourth, reduce your charging time by installing an external, smart, 3-phase regulator used with a high output alternator.