Technical Consultant NOW THAT THE main cruising season has started I have been hearing about problems with batteries and charging regimes. In far too many cases it comes down to not charging for long enough, leaving the batteries partially charged, and then believing the state of charge shown by amp-hour counting gauges.
Such gauges accurately count the amp hours flowing into or out of the batteries but they can only guess at how many of those amp hours are converted to stored electricity – and they have no idea how much battery capacity is lost as batteries age. Over time this leads to gauges overstating the state of charge, so charging is stopped long before it ought to be.
So make sure you read the gauge’s instructions, set it up properly and regularly re-synchronise it. When charging, use the ‘amps’ function and keep going until the charging current has dropped to about one percent of the battery capacity.